April O'Neil is an ally and friend to the Teenage Mutant Ninja Turtles. As of City at War, she is a fully graduated kunoichi after having undergone intensive training with the Turtles' mentor and father figure, Hamato Yoshi, and Fugitoid (2012 TV series). In doing so, she also became an official member of the Hamato Clan.
April appears as a young-looking shy 16-year-old. She has shoulder-length ginger hair that appears to be tied up into a small ponytail and right-sided curved bangs. She also has a yellow headband. April wears an elbow-length black shirt with a yellow and white sport shirt with the number "5" over it, blue denim shorts, black leggings, brown bandages/bracelets around her wrists, white high socks with two blue stripes on them and black low-heeled boots. Though you may not notice it, April has a patch on the right back pocket of her shorts. The patch inspired by Pixar's iconic Luxo Jr. Ball: A round golden patch with a blue outer ring and a red star in the middle. There also appears to be keys that are assumed to be house keys. April is rather slim for her age, with blue eyes with long eyelashes and freckles while standing at average height. Donnie finds all of these features "attractive", leading to his crush on her.
Since New Girl In Town, her pajamas consists of a yellow long sleeve button up shirt, and floral pants.
In The Kraang Conspiracy, she is seen wearing a white long-sleeved, button-up shirt, and white pants when the Kraang was about to gather some of her DNA. Her headband was also changed to white.
Starting from Beyond The Known Universe, she began wearing a yellow space suit over her normal outfit with a white belt and boots.
Since City at War, April has been wearing a black jumpsuit similar to her space suit, with yellow stripes down her arms and sides. In addition she wears her Tanto blade at her lower back and her headband is now black in color.
April is a smart, strange, tomboyish, and shy sixteen year-old girl with an indie rock vibe. April is determined and quite resourceful. She is fiercely loyal to her mutant friends, as seen in Panic in the Sewers. When the turtles are ready to give up, April volunteers to find out Shredder's plot. She is also somewhat reckless, too. She cares about her family, or what's left of it, above all else. Any threat to her father is one that she takes very seriously, and when she finds out that the Turtles are accidentally responsible for his mutation, she becomes enraged and severs her ties with them. However, when she is once again assaulted by Karai, she calls Donnie for help. After he and the others save her, they reconcile.
However, after the events of Bat in the Belfry, April has begun to show signs of mental instability in regards to her Aeon crystal, becoming overly-possessive of it, and going into fits of rage whenever she has parted with it or someone tries to touch it, even using the Turtles' weapons against anyone she sees wearing it to get it back. But after seeing Donnie getting destroyed due to her being controlled by an elder Aeon, April immediately regrets her behavior and apologize to the others for allowing her obsession over the crystal to destroy her friends and family.
April met the Turtles when she and her father, Kirby O'Neil were attacked by the Kraang. She was afraid of the mutants at first, but started to trust them thanks to Donatello. The group was unable to fight effectively as a team, which resulted with the Kraang succeeding in kidnapping April and her father. While she was trapped in their hideout, April tried to trick the Kraang into letting her escape, but her plan failed. Later, the Turtles came to her rescue. Eventually, they succeeded in saving April, but the Kraang got away with her father. Later, the Turtles met April at her aunt's apartment, where she would now be staying. April was safe, but upset over the loss of her father and determined to find him. The Turtles promised to help her get him back. Since then April has become good friends with the Turtles and cooperated with them on various missions.
She shows Michelangelo how to use the Internet to make friends online.
April reveals that she's set up an online message board "to collect unusual sightings around New York... People send in pics, videos...", among which she also gets stuff that might be able to help in her endeavor to find and save her father from the Kraang: She also played a very active role by infiltrating a Kraang hideout and learning their plans to put mutagen in the city's water supply. She was also able to defeat one of their guards on her own, and escape to inform the Turtles of the enemy plans.
April has begun training with Splinter in the ways of the ninja. While she is not on the level of the Turtles in terms of fighting skills, she has shown improvement in matters of stealth and spying.
She refuses to let the Turtles give up, and volunteers to spy on Shredder to find out his plan. At first, everyone rejects, but seeing they have no other way, they allow her to do it. She finds out Shredder's plan: To destroy the sewers with chlorosulfonic acid. After getting out of the building, April says she's going to hitch a ride and see where they go, but Leonardo objects. Because of Dogpound's acute hearing, he hears them over the phone and captures April. Later on, after Raph and Donnie stop Fong and the Foot Clan, she kicks the door of the van open, knocking him out.
April's phone is stolen by some Purple dragons as part of The Foot's scheme to locate Splinter. Her phone is later replaced with a "T-Phone".
April has found out that the Kraang are really after her, not her father.
April asks Splinter to find her a weapon. After trying out several different weapons ending in horrible failures, Splinter settles on giving her a tessen that he had hoped to give to his long lost daughter. It looks like an ordinary fan, but it is in fact made of metal and has a razor-sharp edge.
She becomes a target for the Foot Clan. Karai, dressed in casual clothing, comes up to her, and quickly befriends her. However, April realizes who she is, and tries to run, aided by Mr. Murakami. However, while being good at running away, she is cornered, and pulls out her tessen. Karai compliments the weapon, yet quickly disarms April and utterly overpowers her. April keeps getting back up and fights back, but Karai toys with her and severely injures her. Karai questions what makes her so special, trapping her in an arm lock, and April angrily proclaims what has changed, including the death of her mother. This touches a nerve in Karai, lowering her guard and allowing April to send her tumbling down a subway staircase, and allowing her to escape. Despite her escape, Splinter states she should stay in the sewer temporarily. With the Foot now after her, along with the Kraang and likely thanks to her very narrow escape, she is unsafe out in the open. She reluctantly accepts, wanting the enemies of the Turtles defeated so she can return to her normal life.
She hear something down in the sewer tunnel while training with Splinter. She pursues the sound and discovers that it was a communicate device that The Kraang use to communicate and brought it back to the lair. Splinter is interested in how April could hear something that he couldn't. April says that it could be the reason that the Kraang need her.
She helps Donnie decode the alien communication orb and find out what the Kraang are planning. When the Turtles leave the lair to go and stop the Kraang as well as save the world, April asks Splinter why he isn't going with them, to which he responses by saying that it is his job as a teacher to prepare them for the challenges that they face. She then counters that with the fate of the world and survival of the human race in the balance, he should help. He then angrily resorts that he doesn't have to explain himself to a child and storms out which upsets April a little. She is then approached by her father [Kirby O'Neil] in the lair, who asks where everybody is. April then explains that the Turtles are on their way to the TCRI building. Kirby then informs her that the Kraang know the Turtles are coming and their plan for they have cracked the T-Phone's Encryption. He then convinces her that they must go find and warn the Turtles in person. As they leave, Splinter warns her that is very dangerous for her to be on the surface, to which she coldly replies by saying that unlike him, she can't just sit around and do nothing. As April and father walk through the sewers, she realizes that it isn't the way to the TCRI building. Suddenly, two Foot Clan ninjas appear and grab April. When she is secured, Karai appears referring to her as princess and if she missed her to which April replies by saying that she did and that she forget to give her something before she knees Karai in the stomach. Karai then compliments her father and orders him to take a message to Splinter. April then finds out that he's been brainwashed. He then goes back to the lair with two mousers, ignoring April's cries for help. Splinter leaves the lair and goes to rescue April himself. He makes his way to the headquarters of the Foot Clan and decimates a large squad of ninjas and enters the throne room. He then fights and defeats Dogpound and Fishface, and rushes to April to free her only to discover that she's another mouser hologram. The Shredder then reveals that he used April as bait to lure Splinter out and now that he has, he had no use of April, so he handed her over to the Kraang, who need her for their plans (April, who is handcuffed, is seen being handed over to the Kraang by the Foot soldiers in a alley as the Shredder reveals this).
April awakens and finds herself aboard the massive Kraang warship known as the Technodrome. She then sees the gigantic form of Kraang Prime who's staring down at her. It then explains that her mental energy is uniquely attuned to this universe and once Kraang Prime gains this ability, it will use it to transform the Earth into a world for Kraang (wiping out mankind and all other life on the planet in the process). A swarm of electrodes then converge on April and all goes black (April is heard screaming in the process). The Turtles then come to April's rescue by sneaking aboard one of the capture pods that the Kraang are using to abduct people and animals and are brought to the Technodrome. They hear her scream, but before they can get to her, they are set upon by dozens of Kraang. Within Kraang Prime's chamber, April has been fitted with a terrifying-like helmet device that is siphoning her mental energies and transferring them to Kraang Prime. As Kraang Prime starts to use the energies to start the planet-wide mutation of Earth, the Turtles burst in, having battled their way here. While Raph distracts Kraang Prime by kicking it right between the eyes, Donnie frees April, shutting down the mutation machine with her saying you're my hero, causing Donnie to blush. They then move to escape, but Kraang Prime pulls itself from the wall and pursues them all in it's gigantic robot body. April and the Turtles escape the ship with Kraang Prime close behind them all. Leo then stays behind and fights Kraang Prime himself so April and his brothers can escape in the last escape pod aboard the ship. The escape pod jettisons into the sea followed shortly by the Technodrome itself, which sinks to the bottom of the ocean. April and the Turtles then mourn over the loss of their brother until it is revealed that he managed to escape at the last moment. As the five celebrate their victory, the other pods with the abducted people surface as well. Back at the lair, as the Turtles continue to celebrate, April walks to a quiet Splinter and apologizes for her words earlier. He then tells her that there is no need for she spoke from her heart. Leo then comes over and asks him if something's troubling him. Splinter then replies by saying that he has learned something from Shredder but the revealing of those things is for another time. The Turtles and April continue to celebrate their victory with a dance party. However, unknown to them all, at the bottom of the ocean where the Technodrome lays, it slowly begins to light up and reactivate, indicating that the Technodrome and Kraang will indeed return.
April was nearly saved by her father from a mutagen canister falling from the sky. Unfortunately, her father came in contact with the mutagen, and then comes in contact with bats, causing him to mutate into a humanoid bat. When the Turtles capture him, they tell April they will save her father, but Michelangelo opens his big mouth by saying it was all their fault. April becomes extremely angered, and says she does not want to see the Turtles again.
She becomes the target for Timothy. Donnie talks about her while working on a cure for him and her father, and being lonely makes him go after her to be her friend. She tutors Casey Jones in trigonometry and when Timothy finds them, they fend for themselves. She is still angry with the Turtles and tries to avoid them contently, but still cares about them seeing as she distracts Casey so he wouldn't spot the Turtles.
April still hates Donnie and the turtles for her father's mutation. Karai tries to hunt April down again. The Kraang also try to recapture her with their latest weapon Chrome Dome. Her friendship with the turtles is rekindled after they save her from both Karai and the Kraang. She was also seen hanging out with Casey at the local hockey rink (before they were attacked by Foot-Bots), where he shared his past life about a friend he had once, reminding her of the guilt she made for throwing the turtles and Donnie out of her life.
She first appears at Roosevelt High School walking with her friend Irma to class. they then find and talk to Casey (who has scars on his face from his battle with Raph). She introduces Casey to the Turtles after he sneaks into their lair. She also helps fight off and defeat the Foot-Bots who invade the lair and attack them.
When the Kraang need April's DNA to perfect their mutagen, they kidnap her and plan to extract some of her DNA. Later in the episode, the Turtles have to save her from them while dealing with April Derp and April clones. In order to escape, April actually finds a way to use her alien "powers" in order to flee from their grasp, as she unleashes a psychic blast that renders the Kraang unconscious, as they could not take the force of the blast as it overloaded their hive mind connection. Later, back in the lair, Donnie examines her DNA and reveals to everyone (including April herself) that she's actually a half-Human/half-Kraang mutant hybrid, which shocks her completely.
April is sprayed by the fungus and spends the episode running around the sewers. She believes that her dad (Kirby bat, or Wingnut) is trying to eat her.
The episode begins with her along with Casey and Irma walking on the streets of the city after a tutoring session and getting some gluten-free pizza (which Irma questions). While walking, a rat goes running through the streets which surprises and scares Casey instantly. Irma then questions why someone like him would be afraid of small and harmless rodent. Suddenly, a cat (who was chasing the rat) appears and April immediately takes a liking to it. She then decides to take it home (after seeing that it doesn't have a tag which makes it a alley cat). However as the trio continue to walk, something is watching them from behind. April, the cat and Casey then leave on his bike and say goodbye to Irma; which makes her question where there always running off to and that she's bound to find out eventually. Suddenly, the thing that was watching her emerges from it's hiding place and appears behind her. She then turns around and begins to scream in horror as it begins to attack her. They then go to the lair and enter Donnie's lab where he is (as he continues to work on the Retro-Mutagen) and Mikey (who was eating ice-cream until a large scoop of it fell into a jar of the solution and managed to cover it up). She then asks them if they can look after the cat who Mikey also takes an instant liking to. As the three of them talk, Mikey places the cat on the table where it runs amok and ends up licking the jar (full of mutagen and ice-cream). The then cat mutates and becomes Ice Cream Kitty. Mikey then manages to sneak her out of the room without the others noticing. April is then seen in the kitchen hanging out with everyone. Suddenly Splinter (who has had visions from Victor Falco a.k.a. The Rat King recently) walks in looking for some ice for his headache. He is then denied access to the freezer by Mikey (who has hidden Ice Cream Kitty in there). This causes Splinter to become increasingly mad and he begins to attack the others (while being under The Rat King's control). They manage to hold him down but he breaks free and informs them all (who are all shocked) that he will soon take over the city and then the world. He then calms down and informs them all about the Rat King's return. In the sewers, she, along with everyone else, watches the current news report about the gigantic rodents (who are invading the city while causing total chaos and destruction). they try to convince Splinter (who makes some explicit warnings) about helping them deal with the chaos above but he refuses (knowing the Rat King can easily take control of him). They then head up in the Patrol Buggy while the others show up in other vehicles as they try to fight off the rodents and lead them away from the populace. The plan mostly works as the rats begin to follow them all; However, they manage to turn over one of the vehicles and catch Casey off-guard who they then capture and drag back into the sewers. April tries to help him but fails which leaves her in grief. They all then return back to the lair to Splinter, who reveals that the rat king peered into his mind to learn as much as he could about his mutation so he can mutate the people he has captured into rat people which he will use as his army for world conquest. The team then state that they must stop him, but Splinter (who cares about all of their safety) states that he's grown to powerful for all of them to defeat. They try to reason with him but he commands them to stop. April then tells him that she's believes in him and what he's capable (while mentioning that Casey's life is in danger as well) hoping Splinter will have a change of heart but unfortunately it does not work. The team then gear up and prepare to find the hideout. Quietly, she and the Turtles find and enter his hideout; unexpectedly, they are surprised and happy when their sensei had come along as well, despite his statements earlier. She then goes looking for a lever to release everyone while the Turtles stay hidden (for they cannot be seen). She then finds one and succeeds in freeing Casey and Irma (who begins to talk about rodent facts to which they both reply to by saying "not now Irma"). The trio then find more levers and being to release all of the captured humans. She, along with Casey and Irma, then help lead everyone out of the area as fast as possible. After they do so, they encounter another rodent who Casey (who decides to put his fear behind him) manages to defeat easily. Soon, most of the giant rodents are defeated and the team start to wonder where their sensei has gone off to.
April and Casey are exploring the rooftops of New York City (while patrolling the area for any crimes that might be occurring). She then hears and sees the Kraang in a secluded alley way. She then sees them all lining up in a single file as they enter a portal (that's being opened and controlled by a floating alien technology device). They then jump down and engage the very last Kraang (who's just about to enter the portal). Casey distracts it while April attacks it from behind by slicing it's robot body in half with her tessen. Casey then hits it with his hockey stick making it hit a wall and crawl away. April then instinctively press one of the three buttons on the device causing the portal to close and dissipates the device (causing the piece of tech to fall to the ground). April grabs the device and states that they should take it to Donnie (who she compliments by saying he's advanced) so he can examine the device himself. In the lair, Donnie inspects the device when April shows him how to operate it (by pressing the buttons to activate/deactivate the portal). Donnie is intrigued by the device. Suddenly, Raph jumps into the portal itself which causes everyone else to follow suit; however another earthquake occurs which causes the lab to rattle a little bit which results in some falling debris to hit the device making it deactivate the portal and leaving the team on the other side. Upon entering, everyone is intrigued by the countless portals and views of the variety of dimensions (including the 1987 universe and Dimension X; the infamous home of the Kraang themselves). Unfortunately, they are spotted by the Kraang who send a group of aggressive Biotroids to attack them. They prove to be a challenge but the team manage to destroy all of them except for one (who punches Leo, Mikey and Raph into a portal). A Kraang then appears with an odd looking remote that it uses to close the portal (that the others were pushed into). They attempt to get their hands on it but the Kraang throws it into another portal and leaves (humorously)]. She, along with Casey and Donnie, manages to defeat the last Biotroid by pushing it into one of the portals that leads to Dimension X. However, some Kraang (who are simultaneously forcing an odd worm-like creature through an exit with a bunch of stunners) notice and inform them that they are aware of their presence as they spy on the aliens. The Kraang then send a large squadron of of Kraangdroids through another portal, who confront and capture them (causing them to surrender). They then take them to a New York City subway through a portal. The Kraang continue to lead the three of them somewhere (which is unknown). April then corrects Casey on a question he asked as she states that their going to be fed to something (not get fed something). Unwilling to let this happen, Casey makes an abrupt move on the Kraang in front of him; April and Donnie join in as well. Donnie then manages to use his staff to hit a nearby sewer wheel which releases a bunch of gas into the air that immobilizes and incapacitates all of the Kraang. The trio then escape using a nearby door (which Casey uses a Cricket bat to bar) which leads them to a large and wide, but short, tunnel. They then walk through the tunnel, and at the end of it, they discover four gigantic creatures and a large group of Kraang that come into their view. April takes note that the Kraang are milking one of the creatures for mutagen (like cows for milk). Donnie then discovers and states that the creatures are the cause of the earthquakes around the city and the source of the mutagen itself (which disgusts April). However, unbeknownst to all of them at first, a small, infant Kraathatrogon is sitting right behind April. It cuddles her a few times which causes her to believe that Casey is touching her. She then looks down and discovers the creature which scares them all. Casey then hits it on it's head which causes it to alert the Kraang about their presence. The Kraang then release a giant, adult Kraathatrogon that begins to attack them all at once.
The trio continue to run from the Kraathatrogon that's chasing them (which Casey tries to distract by throwing a paint bomb that it disgusts which fails). They then change directions and find a nearby ladder that leads to the surface. Donnie then grabs on to it and tells them both to grab his Bo. April manages to grab on and becomes secure, but Casey isn't so lucky as the worm comes up quickly and swallows him whole before it wiggles away. This leaves the two of them saddened. They then reach the surface and another earthquake occurs. April states that they must stop the giant alien worms by any means necessary. Donnie agrees and says that the must find the person who knows more about the Kraang than anybody else, Jack Kurtzman. They then go to his apartment and he tells them to get in before their spotted. They then explain the situation to him. However, Jack reveals to them both a bunch of photos and information about the worms as he states he has already dubbed the Kraang scheme as "The Manhattan Project". Jack then explains that he doesn't know how to defeat the giant worms but he does state an interesting fact about the worms who the Kraang ride by pulling their antennas (which also disgusts her). Donnie then comes up with a idea involving salt. April tries to ask him what he's implying but she suddenly receives a phone call from Casey (who's alive and is in the worm's digestive system). April is overjoyed and promises they will come to his aid shortly. They then make their way back underground and Donnie bangs his staff on one of the subway tracks which creates vibrations that successfully attracts the worm to their position. Donnie then tells April to take out the cans of salt in a bag which she questions him about. Donnie then explains that the salt's ionic strength can seep into a worm's system (and blood cells) which will result in it slowing down. They then repeat the process of throwing a can of salt in the air and hitting the worm in it's face which is the mark. Finally the worm stops and throws up, spitting out Casey in the process. They then share a small reunion that is short lived as they discover a Kraang operation base (that they're right in front of) underground. They also see the Kraang who are still in possession of the Kraathatrogon that they can release at any time. Donnie then comes up with an idea to reverse the polarity of the portal located in the large room while April and Casey distract the Kraang. While Donnie pries open the the perplexing piece of technology, April remembers what Jack said about the worms earlier and comes up with an idea. She then climbs on top of one of the worms and rides it by pulling on it's antenna. This works and after destroying some Kraangdroids, she orders the worm to go right up to the surface (exactly right where the turtles are engaged in another large battle). the worm (along with April and Casey riding it) emerge by bursting through a nearby manhole; which shocks everyone. Tiger Claw is then eaten whole by the Kraathatrogon (like Casey was earlier) after being knocked into it by Splinter and a jet-pack malfunction. Donnie finally reverses the portal's polarity which causes everything (April, Casey, the Kraang, and the worm) to start flying toward it and into it. However, Donnie manages to save them both with his staff and shuts it down at the last second. The following day, they regroup with the rest of the team and Splinter (who commends them all on their courage) on the rooftop of the building. They are all happy that they have all succeeded in their own right this time around. Upon learning that Karai is Splinter's biological daughter and wondering where she is; April states that she can't believe that some as wicked as like her (calling her a evil witch) is related to him. She then apologizes about the remark which she believes was honest. Splinter then states that perhaps one day she will accept the truth but that is her decision. Unbeknownst to all of them, she's secretly hiding on a nearby billboard and after hearing what they just said, she's starting to question everything as she has a severe facial expression on her face. The team then leaves as they celebrate their victory.
April is kidnapped by the mutated version of Baxter Stockman. Baxter threatens to mutate her, so the Turtles come to rescue her. When the Turtles come, it is apparently too late. Baxter lowers April down from the ropes that bind her and hang her over a giant container of mutagen. Though Donnie had tried to save her, he failed. But as everyone tenses up, April comes out of the jar normally. It is later found out that she is immune to mutagen because of her alien DNA.
April is kidnapped once more, but this time under the control of a mutant pizza and turned into a mindless zombie. Later, Michelangelo has to save her and his brothers from the mutant Pizza Face. After he does, he wakes up and realizes that it was all a dream. The Turtles and April then come into his room to check on him. They tell him that it was probably a nightmare (when it actually wasn't) before they all leave.
Both Tiger Claw and Karai attempt to go after them after interrogating Mr. Murakami (who informs them about the Turtles friends' whereabouts) at his noodle shop. They first appear exiting a movie theater after seeing a film with Irma. April gushes over the movie while Casey complains about Irma tagging along (as he thought it was a date). April then senses something and informs them that someone is following them. She and Casey decide to split up and ditch Irma. Tiger Claw goes after Casey and ambushes him while Karai chases April. When she catches up to her, April pulls out her tessen and prepares to fight her (while informing her that her training with Splinter has improved and that she's capable taking her down on her own). However, Karai states that she just wants to talk; not fight. April then proclaims that she's been trained for that as well. While April chats to Karai about the insane events that have recently happened, she opens up to her about everything (examples-Splinter being her real father, where her loyalties lied, the Shredder's deception and possibly betraying him), all of which surprises April. Leo and Donnie go looking for her and find the two girls on a nearby rooftop. They appear to enjoy each other's company until the Turtles show up. Donnie then prepares to attack but she stops them in their tracks and tells them both to listen to what Karai has to say. April then tells them that she believes Karai who believes Leo and what he said to her before about Splinter. She then goes back to the lair with Karai and the Turtles. April is then shocked when she sees a wounded Casey (who got thrown off a building by Tiger Claw earlier) and runs to him. She then stays behind with Splinter to attend to Casey and his injuries.
April goes with the Turtles to destroy a machine the Kraang created to switch minds. In the process, April and Casey are accidentally hit by a beam when Donnie tries to shut it down. April and Casey switch brains. They get switched back again a few minutes later but not before Casey makes good use of the occasion to check April's body out, while April scolds him for it.
April is captured by Ho Chan because only her powers could restore his mortality, at the end April defeats him and traps him once again in the cursed dagger he came from.
In The Invasion, April is hanging out with Irma, when Kraangdroids attack. April takes Irma to the Turtles' lair to be safe, but this causes the invasion because Irma was Kraang Sub-Prime all along (who also laughs during the whole attack and revelation). She, Donatello, and Michelangelo make it back to her apartment. They eventually take the Party Wagon where Kraang Prime chases them all down as he tries to take them all out (after mutating her dad again in the process) as well the Foot Clan who also go after them and try to take them out in the apartment. After beating Kraang Prime in the Turtle Mech, she, Casey, Donatello, Raphael, Michelangelo, and an unconscious Leonardo leave Manhattan to take refuge at the O'Neil Farmhouse.
The episode opens with April recounting the events that happened in the finale of season two (which resulted in losing Splinter, Leo being badly injured and losing to the Kraang who invaded and took over New York City). They then arrive at April's old family home in the country at a farmhouse and take refuge there. They then take an unconscious Leo to the bathroom and place him in the bathtub that they fill with water so he can stay hydrated and recover. While there, she continues training with the others and tries to keep the gang together (even though she misses the city, her dad and Splinter). It is also shown that she is a great artist as she draws pictures in her journal as well as writes and narrates the events that have happened in the last few months at the farmhouse. One day, during one of their training sessions outside, April trains with the Turtles and manages to take down Raph by punching him in the face and knocking him out (while mentioning that she's almost a fully-trained Kunoichi). The Turtles then admit that they miss Splinter and that Leo may never wake up as well as the fact that their meant to live in the sewers, not the countryside. The gang then chill down and decide to watch Mikey's new favorite TV show Crognard The Barbarian. Suddenly, Raph (who goes check on his brother) calls everyone to come upstairs where they find a conscious Leo in the bathtub. They then take him downstairs and April serves him tea and biscuits as they tell him the events the events that have occurred and Donnie examines him. Later in the evening, (After Raph and Leo's unsuccessful workout and Leo's mishap with the Mutagen medicine), she chats with the others about Splinter being dead or not while Mikey tries to watch TV when suddenly the power goes out. The fireplace and flashlight die out after as well. They then begin to call out for Raph (who went out into the woods to get wood for the firewood but was attacked by the creature). They then split up into teams (with April going with Casey which disappoints Donnie) and go looking for him in the woods. While they search, Casey brings up the fact that after they left New York he noticed that her attitude towards him had changed, she became distant to him, even cold. But before she can answer, she senses that someone, or something, is watching them. She then hears Donnie (who was teamed up with Mikey and found a shack where they were attacked by the creature's vine-like traps) scream. She then turns around and sees that Casey has disappeared as well. She continues to walk when suddenly she sees the creature who has a pitchfork and is attacking Casey. She then attacks it. They both fight it off. The creature then chases her through the woods after it takes Casey out. She then screams at Leo for help (as she's almost back at the farmhouse) when suddenly a vine comes out of nowhere and grabs her by the heel. It then drags her back into the woods as Leo tries to run toward her to save her (which forces him to go alone into the woods to save them all himself). The creature then takes her and everyone else (who are all tied up) back to the shack. She and the gang are then freed by Leo after he managed to lure the creature out and defeated it. The creature (who Mikey has now dubbed Creep) then returns and after a short battle (which results in Leo pinning it to a tree with the pitchfork while the others play a game of keep away as the creature is after the mutagen medicine), April and Casey tie it up to the tree in chains. Later in Donnie's lab, she and the team are all there (including Raph who wakes up and is informed about the incident with the creature who absorbed all of mutagen from his body that Donnie has returned to his body without any infection and that the creature has turned into goop and has been placed into a jar). They also explain that Leo stayed up all night and never left his side. Leo then states that after he heals they can head back to New York.
Donnie prepares a gift for April that he makes: A music box with a picture of him serving as the mirror for the top. He then presents it to her. She quickly dodges the romantic move and claims that she has some ninja training to do. She along with the rest of the gang are then introduced to Bigfoot who the Turtles found in the woods and brought home to attend to her injuries. She then bandages her arm while she informs them that she's being hunted by a very bad man called The Finger. After the creature reveals it's gender and attraction to Donnie for being so kind and nice to her, the others begin to laugh about the predicament that he's in except for April. She then walks into the kitchen and sees Bigfoot making soup (which smells awful) for Donnie. She then goes looking for ingredients in the fridge and opens the top freezer which exposes Ice Cream Kitty. The two both scream in fear of each other which results in her throwing the fridge outside. She then helps give Bigfoot a makeover as she tries to impress Donnie as well as get his attention. After rescuing Bigfoot from The Finger, Donnie decides to talk to April the next morning as she is then seen chopping wood (for the fireplace) with an axe. He then states that he won't bother her anymore (no music boxes, etc.). He also states that he realizes what he did to her because of what Bigfoot did to him and that he's just a mutant. April starts to look at him sympathetically while he states all of this. She then smiles and says he's not just a mutant but her mutant before she kisses him on the lips which completely shocks him. She then walks away smiling and leaving him alone.
April is seen cleaning around the farmhouse (the bathroom to be exact) with Casey and the Turtles. When Mikey falls and accidentally discovers a hidden trap door that leads to the basement, she is surprised as she didn't even know about it. She, along with the Turtles and Casey, descend down the trap door and they make a shocking discovery; a Kraang scout ship buried right under the house. She then wonders why the alien ship is here. As the team seek answers, they decide to open and enter the ship to find out more. Once inside, they find a stasis pod that appears to contain a humanoid figure within it. Mikey (who ignores Donnie's warnings of not to touch anything) accidentally (using his elbow) turns on a switch which causes the pod to open. As it opens (with the smoke clearing), April gasps with shock for in the pod is her long lost mother Mrs. O' Neil who she believed to be deceased. After Mrs.O'Neil awakens from the pod, she is shocked at the appearance of the Turtles and wonders who they and Casey are. She then looks toward April and both woman faint in the Turtles and Casey's arms as the shock is to much for them to handle. She then has tea with her mother who explains her story to everyone in the living room as they all calm down. She then explains the history between their family and the Kraang as well as why they were after April to begin with. Afterwards, she hugs April and proclaims that they are finally a family again (wondering where Kirby is) only for Leo to lie to her by saying that he is on a safari in Puerto Rico. April then relaxes with her mother on the porch swing near the house only to be attacked by Mikey who tries to attack her due to the fact that he doesn't trust her and has sensed that something is wrong with her. April is horrified by the unexpected assault and pins Mikey for scaring her mother who runs back into the farmhouse crying in fear. Mikey tries to explain but April isn't interested in hearing his reason and goes running for her mother back in the house. April then finds her mother back outside trying to forget Mikey trying to attack her earlier and reflecting on the good memories of the past. She then tells April that they should leave the house and freaks (referring to the Turtles) behind and start somewhere fresh. April is reluctant because of the Turtles being like a second family who have always been there for her and she doesn't want them to go. Her mother then gives her a ultimatum: Her real/biological family or the Turtles. She then walks away leaving April to make a very hard decision. April then goes to the Kraang ship where Donnie (who's trying to figure out what happened to Mrs.O'Neil when she was captured by the Kraang by checking the files) if he's seen her mother. Mikey (who was attacked by Mrs.O'Neil moments before) then comes in and states that she is probably OK and that he will help look for her. April shoots down offer of assistance and leaves as she is still angry at him for doing what he tried to do earlier. April then talks to Casey on the swinging porch about the decision that her mother has left her with. Casey (who's upset about the decision) then tells her that he understands if she decides to leave. Suddenly, Raph (who was just attacked by "Mom-Thing" moments earlier) comes running out of the farmhouse and informs the both of them that everything Mikey said earlier was true but they still disbelieve it. Mrs. O'Neil then comes out of the house and walks toward them all (Raph pulls out his two sais in the process). April then steps in to stop Raph from attacking his mother (after he dubs her "Mom-thing" and asks her what she did with his three brothers). She then grabs April by her arm and states that their both leaving immediately. April then starts to cry at her mother to let go. Mrs.O'Neil then turns around and reveals her true form to April. She then attacks. After revealing her hideous form (a spider-like figure), she chases April along with Casey and Raph (who are all horrified) toward the barn. They then barricade the barn so she can't get in. Unfortunately, she manages to get in by burrowing underneath the barn and bursts inside. April then comes up with an idea to refreeze her but Casey replaces it with a dangerous stunt that involves trying to electrocute it to death using a nearby power box that fails. Casey and Raph then decide to attack it head-on but they fail again as it has them both sucked into it's body by one of it's suction tubes. It then comes towards April who now stands alone and in complete horror in front of the creature who she thought was her mother. It then tells her that they still can be a family and it's all she ever wanted. She then tries to unite her with all of the others it's swallowed by absorbing her as well. April refuses and tries to make a run for it. Unfortunately, it manages to grab her with one of her suction tubes. April resists the creature and her mental powers get the better of her when the situation escalates, causing her to emit a psychic blast that is too much for the creature to handle. This causes the creature to get blown to pieces (everyone is alright and awaken moments later). Back in the Kraang ship, Donnie reveals the truth about the creature after doing some research: The creature was nothing more than an early Kraang infiltration experiment that was utilized with both Mrs. O'Neil and the Kraang's DNA. As well as that, it also retained some of Mrs.O'Neil's memories. However, the creature became too dangerous for the Kraang to handle so they put it into stasis where it wouldn't be any threat to them. Leo tells his brothers not to talk about it for April is disenchanted and feels like she just lost her family all over again. She then states that she believes her real mother is still alive and must be somewhere in the world. Leo then offers her a hand and states that she shouldn't give up hope. Mikey then states that they are also her family as well, making her smile. However, the moment is short lived after Mikey begins to gloat about being right. Donnie and Raph then ask and question him about the mutagen that Mom-thing spilled in the woods.
She appears with the rest of the gang who are angry after they enter the living room where they discover Mikey's mischief as he has made a mess of the place after watching his show with Ice Cream Kitty and trying to imitate some of the moves. They then go out for a while and order him to clean the mess up. However, unbeknownst to all of them, Mikey ran away, while informing Ice Cream Kitty of his safety and that April will take care of her in his absence before he departs. When she and the others return to the farmhouse, they discover that Mikey hasn't cleaned up the mess and begin to complain (except for her). She then points out to all of them, particularly Raph, that they don't appreciate him which is most likely the reason he left. Donnie then comes in and shows them a report of a local camp site about two-legged green creatures that have trashed the place and decide to go and search for Mikey (as they believe it's him). Later on, they will return to the farmhouse (after not finding Mikey) and discover graffiti on the walls that states "Humans Beware" which they immediately accuse Mikey of doing, but Raph points out otherwise. Suddenly, they find a pair of foot prints (that are amphibian) and that hop down to where Leo is standing. April then senses danger.
Suddenly, the Punk Frogs (who are being led by Genghis Frog attack the group (believing that humans, who they also state are their enemies, have captured their reptile relatives who they're trying to rescue). The fight is brief for they are easily outnumbered. Genghis then tells April and Casey to flee, but the Turtles try to inform them that they're not prisoners and that the humans are their friends. He doesn't believe them even when they state that their serious which results in him calling them traitors and attacking them. He and the other Frog Soldiers then capture April and Casey by using their tongues and dragging them off into the forest. They then take the two captured humans back to their tree (which is also their home) where Mikey hears their cries for help. Mikey then tries to explain that he exaggerated some parts of the story that he told earlier when Napoleon Bonafrog brought him to the frog tree earlier. The frogs then imprison him as well (as they believe he deceived and lied to them). Mikey then asks why their leader, Attila the Frog, is doing this. He then tells the story of how he was once a squad of frogs at the pond who's home was bulldozed by humans who built malls, gas stations, coffee shops, etc. over it and how Rasputin the Mad Frog found the mutagen that transformed them. They also reveal that they plan to start a revolution by mutating humans into frog people. Unbeknownst to all of them, the Turtles show up and try to stop the invasion as well as rescue the trio. Unfortunately, their cover is blown and they are spotted. They then face the frogs and are outnumbered again. Napoleon then gets into a conflict with Rasputin while trying to rescue the others and accidentally knocks down a candle making the tree catch on fire. Napoleon then frees and warns the others.
Everyone except for Attila moves to escapes as Casey knocks the frog king unconscious and onto the elevator. The frog king is surprised that humans saved his life, April tells him that not all human are bad adding she believes that not all frog people are bad either.
Her words causes him to reflect on his views before he pays attention to his home burning down. After the fire drowns down, Attila gathers his followers and states that he may have misjudged some humans, which causes April and her friends to smile at his change in views. She and the team are then present for Napoleon's promotion as the new general as well as the frog people's departure into the woods as they begin a journey to Louisiana (where their relatives are). They and Mikey share a snack (a jar of flies and old pizza) which the team find disgusting and finally depart. The gang then return to their damaged home.
April, along with Casey, head for the nearby store. She then shoots down Mikey's request for spice gummy worms; as she puts it, the store either has peanut butter or jelly. While at the store picking up supplies (mostly food), they encounter the friendly but scary store owner Bernie. While checking out, he asks them some questions (such as are they eating for five/six people and if they've felt tired lately) to which they, needless to say, don't really have answers and exit quickly. They then return to the farmhouse to find the Turtles all sleeping. They have no success in waking them up and April becomes worried about their vital signs which all appear to be weakening. After noting that the book from the store may have something to do with the sleeping/dreams, she sends Casey back to the store to investigate while she tries to contact the Turtles with her psychic powers. She appears in different forms in all of their dreams (all of which appear to be their worst fears/nightmares) except for Mikey's. When Casey returns with Bernie from the store, she resorts to slapping them all in the face after nothing else works which causes her to start panicking. After Casey destroys the dream plug, the Turtles wake up (with April kissing Donnie in relief) and the Dream Beavers are released into the real world with the revelation that they're small plush toys. They then leave and Bernie finally falls asleep. Casey and Donnie then remove Bernie from the farmhouse. Donnie asks Casey if April kissed him when he was fading away to which Casey replies by saying "keep dreaming".
She is driving back to the farmhouse with Donnie and Casey after grocery shopping. The two of them continue to argue which results in her stating that she wants them to get along and just have a quiet ride back home. Suddenly, they are attacked by Speed Demon who nearly runs them off the road. They then return to the farmhouse and retell their encounter about the maniac driver to the turtles (who were just watching the local news that reported it). April then tries to reason with Casey to not try and do something about it. She then massages Donnie's neck; after he states that it hurts from the incident (which causes Casey to throw another tantrum as Donnie takes advantage of the situation and gives him a glare to make him jealous). She and the Turtles are then given the big reveal show of the Hot Rod that Casey and Donnie worked on and outfitted with Kraang technology (from the scout ship) and the chicken's Dr. Cluckingsworth intelligence as a navigation system. They then decide to hunt down the maniac driver (who is revealed to be a mutant) and come up with a plan. She, along with the Turtles, drive in the Party Wagon while Casey drives in the new Hot Rod. After being informed by Casey about the car being a mutant and has taken possession of Donnie, they watch and try to figure out what to do as Casey and the mutant car race while being fairly matched. As the mutant car tries to attack Donnie (who Casey frees) and Casey, they then slam into the car and send it flying off of the cliff and exploding (while stating that it will return in the process). In the end, she is thrilled to see them getting along as they congratulate each other. However it is short lived as they obnoxiously begin to praise each other. April and Raph then look on dejectedly at the two and their new relationship which ends with April stating that she thought she was happy that they were finally getting along.
Donatello develops a helmet from the technology in the Kraang ship designed to augment April's telepathy. When she uses it, at first it produces images of a bird, a worm, and a fish, which Donatello believes are mistakes as she is supposed to be blindly seeing flash cards, when as it turns out she was peering into the mind of the yet to be seen Chimera. Then it unleashes an uncontrollable telekinetic reaction, then April begins to see clouds and loses control of her retinas. Later when the Chimera attacks the farmhouse, she realizes that she developed a psychic link with the monster. When the Turtles leave to confront the Chimera , she stays behind with Leo, due to both of them being disabled. Though when Raph, Donny, and Mikey become trapped inside a geyser, she leads Leo to the Chimera's location, motivating him along the way. Once the Chimera is defeated and the psychic link broken, she regains control of her retinas and her sight returns. As Donnie later apologizes for everything that happened April shushes him telling him that she has no regrets and that it was neat to see the world through somebody else's eyes. The episode ends with the Chimera rising from the rubble.
April, along with the gang, train by splitting logs. She then attempts to do the same but instead hits Casey (who was holding the log for her to do it) and knocks him to the ground. She and the others are then informed about the expedition (that the Turtles are about to take in order to connect to nature). It appeals to her as a idea of camping which she likes and disagrees with Casey about it being a bad decision. However, she doesn't succeed in joining the expedition as she is then exempted from the expedition by Leo who states that it's for ninjas only. This upsets her, causing her to state that she's almost a fully trained Kunoichi but is informed by Raph that she's "almost fully trained" (meaning not a ninja completely) which upsets her a little. She then stays behind at the farmhouse with Casey (which he likes but Donnie doesn't). At the end, she continues to train with Casey and finally manages to break the log. She then thinks that Casey has gawked at her accomplishment, only to turn around and see the Turtles (who have also accomplished their spiritual quest) return as they emerge from the forest while carrying a banner and their new gear. She then wonders what happened out there. Leo then makes a declaration by stating that it's time and that they're going back to New York City.
The episode opens with her and the team watching a episode of Crognard The Barbarian watch then gets interrupted by Channel 6 Breaking News which informs them (and everyone else who's watching) that New York City is off limits under military orders. They all suspect this as they watch. April then states that the Kraang may have fooled everyone else but not them before she asks Leo what the plan is. They then go along with Donnie's plan of breaking into the city by breaking through the barriers by using a new vehicle. They convert the old van into the Party Wagon which now has weapons and equipment. With the new van set up, they get ready to go back to the city. As they prepare to leave, she says goodbye to the old farmhouse before they depart. They then leave and make their way back to the city. While driving, they make a plan to park outside the gate and sneak inside so they can find Karai, Splinter and Kirby as well as take back the city. Suddenly, they discover that soldiers have every entrance into the city quarantined. After talking to the soldiers, April notices that they all have Kraang mind control devices on their necks. Her statement causes Casey to drive the van (while speeding and avoiding soldiers and dodging as well as shielding the vehicle as they attack them by firing their weapons at them) and smash the Party Wagon through one of the barriers and right into the city. Once inside, they see that everyone is gone. April then uses her powers and senses that there are only a few hundred people left in the city (meaning millions of New Yorkers have vanished and have most likely been mutated by the Kraang). Suddenly, they run into Kraang soldiers who they easily take out and escape by using stink bombs and soda cannons. They then use the Shellraiser's old access to the subway where they enter. They then avoid some Kraang soldiers and mousers that patrol the area. April then gets asks by Donnie to use her powers to track down Splinter. April then states that since Splinter has become detached from his body, she has know idea what has happened to him. The team decides to look for him at the lair where they come until contact with a Kraang security orb robot that begins to attack only to realize that it detected a scavenging rat. April then senses Splinter nearby and states he is somehow different. The rest of the gang then follow her and find Splinter (who now appears to be acting a savaged rat instead of a master ninja and is attacking everything in his path). They try to calm him down (including stopping him from attacking Casey and biting his face). They then try to talk some sense into him but a mouser who survived his attacks calls for back up and Foot-Bots appear. Despite their best efforts, Splinter is captured and taken to the Shredder. The team then find an access tunnel that leads to Baxter's lab only to get attacked by one of his Mutant Shredder Clones (who happens to be small). After a quick battle, they sneak in and find Splinter (who's still acting like a rat and has been put into a containment cell that has been designed to look like a pet cage for small rodents). Casey then suggests that April should try to reach Splinter's mind like she did for the Turtles in the episode "In Dreams" which Donnie (based on his research) agrees could work. Suddenly, they get spotted by Baxter himself who then unleashes his Mutant Shredder henchmen on them and tries to alert the Shredder (which Mikey unfortunately does for him while fighting the mutant fly). While the Turtles fight, April attempts to reach Splinter by using her telepathy which begins to work as he starts to have flashbacks. Suddenly, he attacks Casey after he mistakes him to be the Shredder. He then attacks April and concerns her to a wall. Luckily from this range, her powers work more effectively and Splinter becomes himself again. After their Sensei rescues them and easily takes out the Mutant Shredder henchmen, they rejoice in being a whole family. However, their reunion is short lived as the Shredder, Tiger Claw and Foot appear and interrupt them. Realizing that now isn't a good time to fight, they escape with Mikey using a smoke bomb as their cover. While in the party wagon, they get attacked by Tiger Claw who they easily dispose of by using a concealed flamethrower attached to the van. They then drive out of the subway and into the city. They then use Antonio's Pizza-Rama as a new temporary home (which was Mikey's idea). April then states that she's worried about her father as her powers give her a weird reading on him and the missing people. She then states that it's like they're right around them and reaches for the front door of the restaurant. Suddenly, she sees her a bunch of mutated people including her dad who are being mind controlled and serving the Kraang by collecting special crystals and other resources within Dimension X.
April appears in Antonio's Pizza-Rama where she, along with Splinter and Mikey, are cleaning up the restaurant that they're using as a temporary home. She, along with Mikey, then notice that something is bothering Splinter who's mind is preoccupied. She then checks in on Donnie who's still working on the Retro-Mutagen. She then asks if it will work and hopefully make her dad human once more. Donnie then states that it will and it will turn everyone (her dad, Karai and everyone else that was affected) back into humans; Unfortunately, Splinter was in the room and heard his daughter's name which saddened him. Suddenly, Casey, Leo and Raph return from a stealth mission to retrieve some of their old stuff from the lair. Splinter, who looks at his old family picture that they retrieved, states that his family will never be completed without his daughter. Everyone resolves to find her and decide to start searching. However, Leo states that April and Casey must both stay behind which causes April to state that they need them and Casey to say that Leo's just making him build up his rage and anger.
April is seen watching Crognard The Barbarian with the others back at their new hideout at "Antonio's Pizza-Rama". Leo then comes in and turns the TV for a meeting about searching for Karai who gave him a clue (the word comet). April suggests that it's her hideout. Donnie then uses his laptop and comes up with three possible locations: a dry cleaner, movie theater or a roller coaster at Coney Island. They then split up into teams of two, with Donnie giving everyone a canister of Retro-Mutagen if they find Karai so they can cure her. April gets teamed up with Donnie and they investigate the dry cleaner. However, unbeknownst to the both of them, she and Donnie have been sensed and are being sneaked up on by a mutated Anton Zeck who, along with Ivan Steranko, decide to get revenge on the Turtles for interfering with their plans of escaping the city and getting mutated by the Shredder. They discover that Karai isn't at the dry cleaners when they arrive. Zeck, who's invisible, shows up and catches Donnie off-guard. April manages to score a hit on him (effectively turning it off). Unfortunately, he traps April with some kind of sticky substance and stuns Donnie (while also finding the retro-mutagen and Donnie's T-phone that he uses to discover where the others are in the process). He then informs Ivan about the other locations and tells him to head to them while he drives there in a tow-truck (with April and Donnie in the back). She, Donnie, and the others (Casey and Raph who were captured by Ivan earlier) are then locked in the back of the vehicle that Leo tries to unlock while Mikey distracts the two mutants. After a fight and confrontation with the two mutants (which involved de-mutating Mikey, using the retro-mutagen to turn themselves human again and Karai showing up and attacking them which causes Ivan to drop the canister), Leo and Mikey free the others and split up to find the two mutants who have split up and are hiding in the amusement park. She, Casey, and Donnie then go into the haunted house to find Bebop who is using his cloaking device to his advantage. He easily takes the boys out and states that he won't hit a girl but he will trip them to which he does to April. Donnie then throws a smoke bomb at Zeck revealing himself. Donnie and Casey then take him down as they both score a hit on him. After the team take both mutants down, Leo calls out for Karai who reveals herself. He then sprays her with the Retro-Mutagen, but it has no effect on her. Donnie then states that her mutation is special. Leo attempts to convince her to come back with them but she declines saying that she's losing her mind (meaning she's becoming more like a snake) and it's too dangerous for her to be around others. Leo then asks why she wanted them to find her to which she replies to by stating that she just wanted to say goodbye to them all before she jumps into the sea. Everyone is saddened by this and heads home.
April first appears when she investigates the commotion that Donnie and Mikey make when Mikey finds a way to make more Retro-Mutagen in the lab in the back of the restaurant. She then appears crouched up in a corner of the restaurant when the team start to plan on how to save the mutated population. She then tells them that they're in Dimension X as she's been having nightmares about them all in her dreams. She, along with Splinter and Casey, stay behind at the pizzeria as they take care of Jack J. Kurtzman (who was attacked and injured by the Kraang earlier) and attend to his wounds.
She makes an appearance at the end of the episode after the Turtles and The Mighty Mutanimals de-mutate the people of New York and return them to Earth (while defeating the Kraang in the process as well). As she and Casey help Jack out of the restaurant, she sees her dad (who once again is human) and runs toward him. They then hug as they are once again reunited.
She is seen volunteering at a soup kitchen alongside her father as they serve and feed the population of New York City as they clean up the city and get back to their regular lives after the Kraang invasion which was all narrated by Casey at the beginning of the episode.
She is first seen watching the news about Muckman that is being reported by Joan Grody with the Turtles and suggests that he's a hero while they see him as a threat. They then find and ambush him in a back alley. Muckman then uses his powers to knock them down (as he blames them for his mutation) but April steps in and prepares to defend them (using her tessen) but Muckman states he doesn't want to hurt her and flees from reporters and fans. April then tells the Turtles to disappear, which causes Mikey to throw down a smoke-bomb; unfortunately Joan manages to catch a glimpse of them and airs it on TV. They all watch it and it enrages Splinter who grounds them all for being exposed. She then helps the Turtles escape the lair by distracting Splinter as she pretends to be in danger. The Turtles then return to the lair (after helping Muckman and defeating Bebop and Rocksteady) and show Splinter a video of Muckman on TV who debunks any rumors about them existing. Splinter (still angry at his sons for disobeying him and leaving the lair) then punishes them all, including April, who tries to sneak away and out of the room, but fails as she is shocked and scared by a silent Splinter who's standing behind her.
She is seen a couple of times in the lair, the first time training with Leo when Mikey asks if they want to hang out, then on her laptop, the third time she is calling Casey about homework, who is hanging with Mikey and not getting an answer. The next time after Raph calls Casey without an answer she says Mikey is also not answering his phone. Finally, at the end, she sees Mondo Gecko and thinks he is cute, but is disgusted when he sticks his tongue out.
She is seen heading home with Casey after seeing a movie at the cinema. While walking, she begins to talk about being wary of everything that has happened but is glad to finally have her Dad back. Casey then pranks her by sneaking around and pops out to scare her. He then told her that the film they just saw was OK but if he was in it, he would have taken the main antagonist down by giving him one good kick. She then tells him that her head fell off to see if he was paying attention as he was still messing around. Unbeknownst to the both of them, Kirby watches them suspiciously as they walk home. Casey then asked her what her favorite part of the film was and she replies by saying the non-stop violence. Casey then told her that it was the fact that the main protagonist never gave up. He then wished her good luck in finding her head (showing that he was paying attention). Later that night, she has a nightmare where she's at the cinema, knowing someone is there. She then demands that they show themselves and the cinema collapses behind her. Suddenly, a giant white snake rises and towers above her. She then starts to run from the snake that begins to chase her. She then gets eaten by the snake which wakes her up from the nightmare. She wonders if it was all a dream and looks under her sheets. She then shockingly discovers that her bed is covered with snakes and begins to scream which Kirby (who is downstairs) hears. He quickly rushes up to her room and discovers her on the floor with a snake that quickly slithers away. Kirby then takes her to the Lair and asks for help. He then explains how she was bitten by a snake while Donnie examines her and discovers some bite marks which scares him. Mikey wonders if she'll be alright as well. He later treats April and explains that her condition is getting worse which leads to Leo asking how poisonous snakes even got into her room. Donnie continues to treat her but explains that, unfortunately, none of the anti-venoms appear to be working or have any effect which means her life is at risk if they don't find a cure soon. Donnie and Kirby continue to take care of April but nothing changes. Suddenly, Splinter enters the room and reveals that he has an ancient poison draining mantra that he says will save April. Kirby (who's upset about his daughter current status) becomes enraged and angrily blames Donnie for not curing her only for Leo to interrupt as he reveals that they have another problem (which is Mikey, Raph and Casey all being bitten and captured by Karai and Foot-Bots). Splinter demands silence and begins the process of removing the poison from April's system which ends with Leo and Donnie leaving to go and rescue the others as he does this. Splinter then takes her and Kirby to the dojo and begins the mantra. While performing the healing hand on her, Kirby watches her heart rate rapidly change from high to low. As she's in pain, her dad becomes extremely worried as Splinter continues the mantra until her heart rate returns to normal. Kirby then asks Splinter if he successfully removed all of the poison but he states that he only slowed down the process meaning that April isn't out of the woods just yet. Splinter then tells April and her dad that he can only stall the poison but it's up to her to fight back and get rid of it for good. Kirby states that he wants to take her to a hospital but Splinter refuses as he tells him that there is no cure for the venom and the mantra is the only thing that can save her now. Splinter then performs the healing hand on her again (as does Leo who uses it to defeat Karai and save the others). After saving the others, Leo brings them back to the lair, where he and Splinter use the healing hand to heal them all as April and Kirby watch. April the realizes that it was Karai who did it all. Donnie then states that she is under the Shredder's control so she shouldn't be blamed for the attacks or her actions.
She appeared briefly in a photo that the Turtles had. She, along with Casey, began to vanish as the Turtles attempted to save Splinter and not mess with time.
She is seen in the lair aiding to Raph's knee injury. She, along with the others, are forbidden from any more missions by Splinter after the Turtles last failed attempt to steal a mind-control worm from the Shredder's lair. After watching the Mega Shredder on the news, Splinter allows them all to leave. She, along with Donnie, Raph, and Casey, use the Turtle Mech to take on the Mega Shredder on the streets as it rampages through the city. With help from Leo and Mikey, they manage to defeat it and destroy it by launching a toxic barrel which it eats and causes it to completely explode.
She is fighting Leo in the dojo while Splinter congratulates her on her skills. She then begins to worry about Donnie, who begins to act weird. She then goes to he lab with him to give him a fresh DNA sample only for them to discover that the lab has been trashed by the Creep (who has escaped from the confinement of the jar he was encased in). She then begins to worry more about him when he starts to forget things and accidentally calls Mikey "Raph". She then goes to the freezer to get him a ice pack. She gets a ice pack from Ice Cream Kitty and talks to Splinter, who states that "sometimes the best solution only arrives when you take a step back from the problem". He then asks her to close the fridge for Ice-Cream Kitty will melt. She and the rest of the team arrive shortly at the dojo after Leo is attacked by the Creep. The Creep continues to attack until Splinter throws him out of the dojo. They all then go back to the lab and Donnie begins to question how the Creep managed to escape. They then realize that the Creep took Snakeweed's claw. They then take the Shellraiser to track down the Creep. April manages to pinpoint the location of the Creep and the guys (except for Donnie) move to find him while she stays behind to watch Donnie. She then manages to turn the Shellraiser back on only for Donnie to go missing. When the Turtles can't defeat the Creep and Son of Snakeweed, they lure them to the Shellraiser where April takes them both out by shooting balls of fire at them which engulfs them. They then take Donnie back to the lair while the Creep and Son of Snakeweed combine and become Creepweed. Back at the lair, Mikey creates an antidote with pepperoni and Donnie takes it which only makes him dumber. They begin to argue when an earthquake occurs. They then notice that Creepweed is causing havoc throughout the city. She, Splinter, and Donnie stay behind while the Turtles leave to investigate. She then suggests Splinter's healing hand technique which he states is doubtful. After Donnie defeats Creepweed (and his intelligence returns thanks to Mikey's antidote which worked), she is seen with the team back in the lab as Donnie stores Creepweed's remains in a locked metal box on a shelf. Donnie then thanks Mikey and insults him which he doesn't realize at first but after a moment does and lunges at his brother in anger.
A team effort by Shredder's henchmen, led by Karai, manage to capture the Turtles and April, in order to lure Splinter into fighting to save them and finally be eliminated. While the Turtles are each placed in a specialized trap designed specifically for each of them, April is left shackled in the control room with Karai to watch the Turtles suffer, then watch Splinter fight Karai, doing her best to encourage him not to give up, while April attempts to undo her shackles. Though the Turtles manage to save each other from the their respective traps, April is unable to help Splinter save Karai after he hits her with his healing mantra, and as the effects of the mind-control worm on Karai's mind are severed, she falls off the platform into the draining water surrounding the platform and is sucked into the drain, while Tiger Claw leaves via his jet-pack, laughing victoriously at how Splinter still lost his daughter at the cost of coming to save the Turtles and April. However, hoping that Karai is still alive somewhere, April, Splinter, and the Turtles, return home.
The Turtles, April, and Casey, soon encounter Bishop, one of many Utrom who are not under the control of the Kraang Hive Mind under Kraang Prime, who brings a warning of the impending invasion by the Triceraton Armada, and how Kraang Prime and Kraang Subprime are attempting to reactivate the Technodrome, to resume their own invasion. Despite the Turtles, April, and Casey's best attempts to stop Kraang Prime and Subprime, the Technodrome is destroyed by the Triceratons, who then prepare to unleash their doomsday weapon, the Heart of Darkness Black Hole Generator, on the Earth to wipe out the Kraang, and humanity as well. Traveling to Washington Square where the doomsday weapon is deployed, despite assistance from the Mighty Mutanimals, the Turtles and April are sorely outnumbered, especially when Bishop's Norman body is disabled and he scampers off in fright.
Before the Turtles and April are forced to retreat with Slash, Dr. Rockwell, and Casey being captured and additional Triceraton troops being beamed down to defend the doomsday weapon and spread out over Manhattan, the team has gained some valuable time. With Slash's damage to the Heart of Darkness detonator buying them some time while it is repaired, April joins Master Splinter in turning to the Shredder for help with stopping the Triceratons. Though Shredder is reluctant because he is being asked by his sworn enemy into joining forces, April is able to convince him to the uneasy truce by mentioning how if the Earth is destroyed, Shredder will never see Karai again. With Shredder now offering his aid to fighting the Triceratons, April and the Turtles are able to rescue Casey, but tragedy strikes when Shredder puts his vengeance against Splinter over seeing Karai again, and murders Master Splinter in cold blood moments before they could have stopped the Heart of Darkness. April is so furious over Shredder murdering Splinter and betraying them, she sends him flying with a psychic blast in retaliation. As a result, the Black Hole Generator activates, and Earth begins to be sucked in. April, Casey, and the Turtles are spared the fate of everyone else when Prof. Honeycutt, a.k.a. the Fugitoid, arrives in the Ulixes, and transports them to safety, before telling them of their coming plans to prevent Earth's destruction by the Triceratons.
Following Earth's destruction, the Fugitoid takes April, Casey, and the Turtles, back in time six months to before the Triceraton invasion, with the objective being to stop the Triceratons before they acquire all three pieces of the Black Hole Generator and use it on Earth. When shown the Fugitoid's armory, April suits up in a yellow jumpsuit with a handheld blaster to use alongside her tessen fan from Master Splinter. When she first steps outside of the Ulixes, amazed by space, she just wants to float away and never go back to the ship, but when the ship is besieged by asteroids, she is forced to return to it before the ship has to land on the planet Varanon for repairs and refueling. While exploring the spaceport, April comes across a valuable mood crystal, but when it is knocked out of her hands and shatters on the ground, she tries to apologize to the alien merchant, who assures her that it is no problem as it was on sale, but for a very high price of alien currency, which April has none of. As a result of April being unable to pay, the merchant becomes hostile, and chases after her with a laser blaster, demanding she pay for the damaged goods, until April runs into Lord Dregg, forcing the merchant to forget about April owing her for the mood crystal and run for her life to avoid Dregg's wrath. When Dregg takes on the Turtles, Casey, and April himself after his Vreen bodyguards are slain, he captures April and wonders if she is of the Terran race, a.k.a. humanity. April replies that she is, and on Earth, her kind squash bugs, which only enrages Dregg to where he tries to eat her, before she blasts him in the mouth with her blaster, forcing him to release her, and allow her, Casey, and the Turtles to flee back to the Ulixes and escape Varanon, before Dregg gives pursuit in the Hornitron and sends more of his Vreen drones to attack the Ulixes. They are all eliminated, and the Fugitoid is able to warp the ship to safety, but it is out of the frying pan and into the fire as April and the others find themselves surrounded by Triceraton Raptor Fighters, having emerged from warp right on top of the Triceraton Armada.
When April and the rest of the gang are shot down by Triceraton Raptor Fighters, they crash on the ice-cold moon nearby, along with the Salamandrians that Raph and Mikey later name Mona Lisa and Sal Commander. With the Ulixes in need of major repairs, and the life-support on their suits only having a few hours on them before it shuts down and leaves them to perish in the subzero weather, they attempt to find a source of irrilium metal to repair the Ulixes and save their lives. They soon run into the Salamandrians, and a battle ensues when the Salamandrians take Leo's offer of cooperation as one of their signs of combat by mistake. After the Salamandrians leave them after they are buried under snow, Raph breaks off to still try and broker an alliance with the Salamandrians, helping to save them from several Ice Dragons, allowing the Salamandrians to help save April and the others from more Ice Dragons. They soon find the irrilium and take it back to the Ulixes, while losing the pursuit of the Ice Dragons thanks to Casey's photon pucks. However, once back at the Ulixes, April and the others' life-support in their suits finally run out of power, and they begin to pass out and succumb to the freezing temperatures, but the Fugitoid is able to repair the Ulixes in time and get everyone safely back aboard, saving their lives, including April's. With new allies in the Salamandrians, April and the others take off to resume their search for the Black Hole Generator.
As the gang continue their search for the Heart of Darkness, they come across an abandoned space ship and decide to investigate. As they do, April has a bad feeling about it, and Casey wishes to see some action, like some zombies. Unknown to the gang, a hyper cube carrying a genie-like space alien called Wyrm, overhears Casey and grants his wish, reanimating the crew as zombies for Casey to fight before the gang is able to retrieve the hyper cube and return to the Ulixes. Back on board, despite April's objections, and mostly due to curiosity, Casey releases Wyrm, who soon manages to get the gang to make two more wishes, releasing him from his hyper cube imprisonment and allow him to run rampant and make April and the Turtles' lives a nightmare, until Casey offers to join him and requests one more wish before finishing April and the Turtles off. Unfortunately for Wyrm, Casey's extra wish is to undo recent events, putting everyone right back to before Casey made his first wish, where right as he starts to make it, April intervenes, having a gut feeling that something is not right and Casey should not say another word. With that, the gang return to the Ulixes at the Fugitoid's request, leaving Wyrm trapped in his hyper cube prison, pleading for them to make a wish and let him out, to no avail.
Continuing their search for the Black Hole Generator pieces, April is being trained to hone her psychic powers with the Fugitoid. Soon, the gang are attacked by a bounty hunter hired by Lord Dregg to attain his revenge on them by the name of Armaggon. An attempt to escape him leads them to an old space station that, unknown to them, had been shut down by the crew as the station's A.I., Overmind, had deemed all organic life to be a threat and wanted to eliminate it. As April and the others investigate, Overmind manages to possess the robotic body of the Fugitoid, while Armaggon activates the station's robot assembly line to create an army of VX3 Warbots to eliminate April and the others. Soon, April, Casey, and the Turtles are captured by Overmind to be made into loyal robot drones to serve him, but are saved by Armaggon after Dregg wanted them brought back alive. Realizing the only way to stop Overmind is to get the Fugitoid back in possession of his body, April uses her psychic powers to reach Prof. Honeycutt's human mind within the Fugitoid's body, allowing him to retake control, before using his Fusion Generator to overload the station's power systems and cause it to self-destruct. April and the rest of the team, sans Leo, are able to make it back the the Ulixes and escape, and Raph is able to rescue Leo after Armaggon is presumed dead after crashing into, and destroying, Overmind's hard drive. The Fugitoid soon locates the Triceraton Armada, and as April and the others resume their pursuit, none of them realize that Armaggon is still alive, and still after them to collect his bounty.
Arriving at the planet of the Aeons where the first piece of the Black Hole Generator is located, April soon finds herself struggling to maintain order among the Turtles and Casey when they start lashing out at each other due to the planet's dark atmosphere affecting their anger and tempers, until they soon locate an Aeon artifact that directs them to the temple where the piece is located. Unfortunately, Captain Mozar and his Triceratons arrive, and despite their best efforts, April and the Turtles lose the first piece to the Triceratons, who then trap them in the temple to perish while Mozar escapes with the first piece. However, using her psychic powers, April is able to locate the Aeons' Sol Star, and return it to the top of the temple, where its power restores the planet to its pristine state and turns the Aeons back from their corrupted forms. As a token of their gratitude, the Aeons bestow a piece of their Sol Star to April, promising that it will bring her and the Turtles luck and great power in their quest, before taking their leave. Back aboard the Ulixes, April listens to the Turtles talk about how the first piece of the Black Hole Generator was able to corrupt the Aeons, and then looks back at her gift from them with a smile.
Following a lead on a criminal contact the Fugitoid knows, Vrax Belebome, who has knowledge of the schematics of the Triceraton Armada's flagship, April and Casey have to stay behind on the Ulixes while the Fugitoid and the Turtles travel into the cantina where Vrax is waiting for them due to how the cantina does not take kindly to Terrans. After the Turtles and the Fugitoid return empty-handed due to Vrax having been angered by Mikey before they made the deal and increasing the cost to twice as originally agreed upon, April soon finds herself being asked to help save Mikey as his brain has been invaded by microscopic aliens know as the Neutrinos, sent by Vrax to extract what knowledge Mikey has on the Black Hole Generator for him to sell to the highest bidder, such as Lord Dregg. While Mikey's brothers are sent into his mind to help save it, April uses her psychic powers with the aid of the Fugitoid and Casey to help direct the Turtles to where Mikey's true self resides in his brain: In his imagination. In the end, the Neutrinos are defeated, and April watches as Mikey crushes their ship underfoot, before the Turtles return to the cantina and get the schematics for the Triceraton flagship from Vrax, with Mikey getting some retribution of his own for what Vrax put him through.
With the schematics of the Triceraton flagship in their possession, the team prepare to take back the first piece of the Black Hole Generator. April is asked to stay on the Ulixes with Casey and the Fugitoid to oversee the Turtles' infiltration of the flagship. However, things fall apart when the Turtles are caught by newly-promoted Admiral Mozar and then sentenced by Emperor Zanmaron to be pitted in the Tri-Arena. April is forced to infiltrate the flagship with the Fugitoid and Casey, but upon being caught by Mozar after getting past the security, April and Casey head for the main armory while the Fugitoid is captured and brought before the Emperor. Avoiding the guards as they head up to watch their champion, Zeno, take down the Turtles, April and Casey reach the armory, where April uses the gift from the Aeons to focus her psychic powers to open the doors. Once inside, April finds several of the Triceraton devices that were used to capture Casey and some of their allies during the invasion of Earth, and uses one to carry the first piece of the Black Hole Generator out of the armory, only to soon run into two of the guards, who force April and Casey to run for it with the piece as they shoot after them. April and Casey then run into the Turtles and the Fugitoid, who had managed to escape thanks to Zeno, and had taken Emperor Zanmaron hostage to ensure their escape. In the collision, the Emperor's crown is knocked off, and though April and Casey's pursuers hold their fire under the threat of hitting the Emperor in the crossfire, Zanmaron and Mozar order them to forget about the Emperor and stop the Turtles. April leads everyone to the nearest airlock, telling them to hold their breath as she hits the button to open it and suck them out into space. As everyone does as she told them, April uses her powers and the Aeons' gift to summon the Ulixes' stealth ship, allowing them to escape back to the Ulixes, and then make good their getaway with the first piece of the Black Hole Generator before they could be stopped by Triceraton Raptor Fighters. With the first piece secured, April asks the Fugitoid where the other two pieces might be, and as the Fugitoid has a good idea where they are, the team set off to find the rest of the Heart of Darkness and destroy it before the Triceratons can use it on Earth.
While the Turtles and the Fugitoid head to Dimension X to meet up with the Utroms, April and Casey have to stay behind in the Ulixes, much to their anger. April tries to read a magazine to distract herself from being unable to go see the Utroms with the Turtles and Fugitoid.
Now with the knowledge of the location of the other two pieces of the Heart of Darkness from the Utroms, April and the others set course for the Cosmic Ocean of Varuna. As they arrive, they encounter the guardians of the second piece, the Daagons, who are at first hostile until the Fugitoid presents the symbol of the Utroms, at which point, the Daagons stand down and escort April and the others to their leader, Hiidrala, who explains that if they want the second piece, they must prove themselves worthy to its guardian, Cthugga, first. After they set off, they are attacked by Armaggon, who manages to get aboard and take Leo hostage, forcing April to drop her blaster and surrender. As they approach where Cthugga resides, April uses her psychic powers to detect it, and soon has to hang on for her life as they try to escape the behemoth, screaming when it looks like it will eat them before it crashes into an asteroid and allows them to hide from it until she is able to sense it leave with her psychic powers again. The Daagons soon arrive to apprehend Armaggon, and upon returning to Hiidrala, April and the others plead for another chance to prove themselves, but Lord Dregg and his Vreen arrive to claim the second piece themselves. April joins in the battle, fighting off Vreen drones, until Hiidrala summons Cthugga to devour Dregg and Armaggon. Without Dregg's hive mind, the Vreen are forced to retreat without further conflict, and Hiidrala awards the second piece to the gang for their heroism and assistance in protecting her kingdom. With two pieces in their possession, the gang set off to find the third piece, though April is saddened to be leaving the Cosmic Ocean because of how beautiful it is in her eyes.
April was fast asleep with Casey Jones on the Ulixes during when the Turtles are summoned by their 1987 counterparts to stop Krang and Kraang Subprime with Krang's plan to destroy the 1987, 2012, and Mirage universes with Krang's weapon, the Dimensionalizer.
When the Triceratons are able to track down the Ulixes and attack it in an attempt to take back the first to pieces of the Heart of Darkness from the gang. April is horrified when debris from the Rock Rocket hitting the Ulixes decapitates the Fugitoid. When the Skeevix Virus is unleashed on the Ulixes, April goes with Casey and one of the Turtles to track it down, only to find them attacking the Ulixes' power core after evolving, having to kill all of them after they manage to disable the power core. Soon after, when the pilots of the pursuing Raptors attack the ship directly, April is able to fight off the lead pilot before the Fugitoid finishes him off, but the other two pilots manage to escape with the pieces of the Heart of Darkness. Despite the loss, April remains hopeful with finding and destroying the final piece before the Triceratons get it first.
As the gang continue their search for the final piece of the Black Hole Generator, they receive a call for help from Mona Lisa as Sal Commander has been captured by Armaggon and taken to Lord Dregg's home planet of Sectoid 1. Once they land, it is not long before April has to take Donnie back to the Ulixes with the Fugitoid after Donnie is stung several times by a Xaxx Bee and infected with its venom. Worried for his well-being, once Donnie is given the anti-venom and cured, April gives him a kiss to show how relieved she is that he's alright. Together, they travel to Dregg's castle, where April creates a distraction with her psychic powers to cause Dregg to attack Armaggon under the pretense Armaggon threw something at Dregg intentionally. Once they are busy, April rescues the others from the Scorpinoid, and once the Fugitoid blasts a way out, they return to the Ulixes, only to have to do battle with Dregg until he is defeated by Raph and they are able to get an severely injured Mona aboard the Ulixes and treat her injuries. April is witness as Sal Commander offers his and Mona's deepest apologies for betraying them and ask for their forgiveness.
As the team make their way to Magdomar, home of the guardian of the final piece of the Black Hole Generator, Tokka, they find that Mozar and the Triceratons are already there and beginning their search of the planet for the piece. Thankfully, the team find it first, but are attacked by Lord Dregg. He manages to damage the Ulixes, causing it to crash-land, and leaving April, Casey, and the Turtles to go after the piece on foot, where they are attacked by Dregg again. During that fight, April uses her psychic powers to turn several of Dregg's chest missiles back on him. They later get into a quick scuffle with Mozar and his men, but escape to go after the final piece again, only for Tokka to awaken at that point to defend the piece. While the Turtles go for the piece, Raph leaves a baby alien turtle he befriended named Chompy Picasso with April and Casey, who soon find that Chompy is Tokka's baby, and April returns Chompy to Tokka without trouble. Unfortunately, though the Turtles free the stuck piece, Dregg steals it and delivers it to the Triceratons. As the gang set course back home to Earth, April discovers Mozar hacking into their communications to gloat at how he plans on using the Heart of Darkness on the Earth, much to her and the others' horror.
With the Ulixes returning to the Milky Way and Earth, April is happy that she'll be able to see her father again after so long, before being reminded that if they fail to stop the Triceratons now, Earth is lost forever. Sensing something else on Prof. Honeycutt's mind, April asks him what's wrong, and the Fugitoid confesses to the Heart of Darkness being his creation, not the Kraang's, having been paid off by Kraang Subprime to convert it from an energy generator to the doomsday weapon it now was to further fund his research. April is shocked by this, and can't believe it. She's even more worried when Leo, in a desperate and furious mood after learning that revelation, goes after the Triceraton flagship alone, and is nearly killed as a result while the Ulixes nearly crashes on Mars. Once Leo is retrieved and resuscitated, they continue to Earth, just in time to watch their past selves already engaging the Triceratons in combat to stop the Heart of Darkness like last time with the Mutanimals, Muckman, Mondo Gecko, and Master Splinter. When the Fugitoid explains his plan on having April, Casey, and the Turtles aid their past selves while he retrieves his doomsday device, April senses that the Fugitoid is lying about his real intentions. Instead of telling them the truth, he ejects them from his ship when they refuse to cooperate, leaving them to carry out his original orders. Meeting up with her past self, April is able to help overpower Captain Mozar when he beams down to confront everyone after Leo destroys the detonator, disarming the Heart of Darkness, then bear witness to the Fugitoid's true intentions as he sacrifices the Ulixes, and himself, to destroy the Heart of Darkness and the Triceraton flagship once and for all. Saddened by his sacrifice, April then focuses on how there are now two of her on Earth, interested in the prospect of having a twin sister, before the past Ulixes and Fugitoid arrives to pick up the past Turtles, April, and Casey, to take on a journey through space, thereby cleaning up any loose ends in regards to two of the Turtles, April, and Casey being on Earth, and allowing the future April, Casey, and the Turtles, to return home with Master Splinter and all their allies, glad to know the Earth is safe from annihilation for good, and they've got a lot to tell their friends and family in the days to come.
With the Kraang and Triceratons gone, and Shredder and his forces having fled Manhattan for the time being, possibly for good, April is promoted to full Kunoichi status by Splinter, being given a ceremonial tanto blade to symbolize her new rank, with the Turtles and Casey in attendance. She has also repainted her jumpsuit from her time with Prof. Honeycutt to where it is now all-black save for a yellow stripe down the sides of the sleeves, torso, and legs. However, during her first patrol with the Turtles, they encounter a sorceress by the name of Shinigami, who manages to overpower all of them and take April's tanto as a souvenir. Following her to Shredder's old headquarters, April discovers her handing her tanto to Karai, and confronts them. Joined by the Turtles, April learns that Karai is on their side finally, free of the brain worm Shredder had infected her with, and plans on rebuilding the Foot Clan to before it was corrupted by Shredder, along with wiping out Shredder's criminal empire, before personally ending Oroku Saki's life once and for all. Thanks to her psychic powers and the Aeons' gift, April can tell Karai is legit in telling them the truth, but before the Turtles leave, April wants her tanto back. Karai agrees to allow April to face Shinigami again, but during the battle, April's anger and rage is amplified by the Aeons' gift, causing her to unleash powerful psychic blasts that crack the glass around Shredder's old throne room. Karai ends the battle before things escalate, then has Shinigami return April's tanto anyway, but still consumed by her anger and the Aeons' gift amplifying it, April begins to draw her tanto, possibly to draw blood, before Donnie intervenes, telling her to calm down and not let herself be consumed by her anger. Returning to their sewer lair, April contemplates giving up her Kunoichi status before Splinter decides to teach her the advanced move known as The Dragon's Tail. Later, April receives a text message for help from Karai and Shinigami, who had attempted to destroy a hidden cache of illegal weapons belonging to the Shredder, but were caught and captured by Tiger Claw, Rahzar, and Fishface. During the battle, April fights with Fishface, before he overpowers her, but then saves Karai and Leo from Tiger Claw when she blinds him with a dust cloud, before delivering The Dragon's Tail to Tiger Claw right in his Achilles' heel, leaving Tiger Claw on his knees in agonized pain, before Mikey drops a smoke bomb to allow the Turtles, April, Karai, and Shinigami to escape, leaving behind enough explosives to ensure the destruction of the weapons cache. Back in the sewer lair, Karai and Shinigami apologize to April for before, and April forgives them, before being commended by Splinter for her actions that night, stating that April has the spirit and tail of the dragon, but April and the Turtles know full well that with Shredder still out there, things are about to go from bad to worse.
April is at the lair with the other Turtles when a Channel 6 broadcast reveals that Hun and the Purple Dragons have been arrested by the NYPD after the destruction of a temple revealed to be the front of a money laundering operation. When Leo leaves following some wisecracks about Karai, April has a funny feeling that Leo might be working with Karai behind Splinter's back. Later, she and Splinter are shocked and horrified when the Turtles return with a badly-injured Donatello following an explosion at Auman Chemicals that Donnie saved Raph and Mikey from. As Leo sulks over allowing Donnie to be hurt because of him, April tries to reason with him, reminding him that he's their leader and they need him. She remains behind with Splinter to help heal Donnie while the others go help Karai with taking down Auman Chemicals and Shredder's Foot-bot factory. She's relieved when Donnie makes a full recovery, but upon seeing Karai returned with the others, she's livid at how Karai has the guts to show her face after what happened with Donnie. Despite that, she bears witness as Karai decides to stop taking out Shredder's criminal empire and focus her efforts on taking down Shredder himself.
After being stunned to see Raph is no longer afraid of bugs after he flicks a cockroach off his pizza, and knowing that Shredder is still out there, April teams with Donnie to patrol Brooklyn in the Party Wagon, only to soon lose contact with Raph and Casey when they investigated a bank robbery the NYPD were responding to. Meeting up with Leo and Mikey, they soon find Raph cowering in a dumpster in a state of hysteria due to his fear of bugs. After Mikey smacks him back to his senses, they learn that Casey has been captured, and learning that Stockman is behind it, April attempts to track him using her psychic powers and her Aeon crystal. Following him to Karai's after he abandoned his previous lair knowing the Turtles would head there first, they attempt to save her and stop Stockman, but due to Raph suffering another hallucination from his bug phobia, Karai is captured, along with Leo and April. Stockman takes them to a skyscraper construction site he's made his new lair on, intending to use them as food for his bug mutants, only for April and the others to be rescued by Raph and the other Turtles, equipped with new grappling packs that Donnie designed, and Raph using a mantra Splinter taught him to overcome his bug phobia and focus on the fight. Once free, April teams with Karai so the two Kunoichis can take down Stockman, but he manages to escape, leaving his mutant lackeys to be captured by the Turtles.
April reports to Donatello that she has been having headaches and strange nightmares about space and other galaxies, which Mikey credits to her Aeon crystal since she's been relying on it more lately instead of her skills and training. When Donnie offers to analyze it, April slaps his arm away in hostility, telling him to back off because it's her crystal. When Mikey says she's being overly-protective of it, April reluctantly parts with it so Donnie can analyze it. When Donnie unleashes some sort of spectral apparition from the crystal with his space bo staff, April is startled by it, but puts it out of her mind when they later receive word from Casey of a monster attacking the surface. Mikey recognizes it as Monoculus, the monster from his Wingnut and Screwloose comic book. After the others are bested by Monoculus, April steps up to fight him, revealing she took her Aeon crystal from Donnie's lab while he was still analyzing it. Donnie is shocked she did that, but April retorts that it's hers and she needs it, using it to focus her tessen to cut through Monoculus repeatedly, destroying it. As she inquires as to what it was and Mikey reveals that it came from his comic book, Donnie suggests that she return to his lab so he can run more tests on her crystal, to which April does not respond. Later on, she returns to Donnie's lab to find her crystal missing, and goes ballistic trying to find it, tearing Donnie's lab apart, and snapping at him when he tries to help. Splinter intervenes and tries to calm April down, telling her that she is too attached to that object, and is using it as a crutch. April tries to deny this, but it is clear that without it, she is seriously rattled mentally. Soon the Turtles get a call from Mikey and Casey, who try to cover up the fact that they took April's crystal without her knowing about it, and recent events with it as well, but April overhears everything and explodes at Mikey in fury for taking her crystal without her permission. She and the other Turtles arrive at the Bell Tower Lair via the Turtle Blimp, where the brought-to-life Wingnut and Screwloose are fighting Mikey and Casey, having become more animalistic thanks to April's crystal. When April sees Wingnut wearing her crystal around his neck, livid, she opens fire with the Turtle Blimp's garbage cannon, hitting Wingnut, but then striking the church tower's bell, causing Wingnut and Screwloose to cover their ears in pain from the ultrasonic noise. With Mikey keeping them subdued, and following Donnie's advice, April is able to psychically retrieve her crystal and return Wingnut and Screwloose to normal, while also calming down now that she had her crystal back. After she returns Wingnut and Screwloose to their comic book, while Casey, Raphael, and Leo comfort a crying Mikey, Donnie suggests she return to the lair so he can run more tests on her crystal, but April sternly refuses. As Donnie asks with concern if April is alright, April replies that the crystal is hers, and she is never taking it off for anyone or anything, ever again...
April and the Turtles meditate with Splinter for only 10 minutes since Splinter had a dream with Shredder being now a mutant but Splinter assures nothing bad will happen to him. She assists to Chris Bradford on TV but Splinter interrupts because he wants them do something else than watching TV but then there's a power outage and Donnie isn't the responsible. They go to check on Karai but Shredder, as the mutant Splinter dreamed, captures her and almost kills them if they didn't get out of the Shellraiser in time. April got injured from the accident and tells Splinter that Shredder really became a mutant and has Karai so Splinter decides to go with them and rescue his daughter. They arrive to the part of the sewers that was seen in The Invasion and find photos about Splinter's past with Tang Shen and Karai as a baby that are put ablaze due to a fire blast that the group dodged if April didn't warn them without her Aeon crystal. They arrive to the same subway station Karai held the Turtles captive back in The Deadly Venom and find more photos that are put on fire. They hear Karai's yell and are separated from Splinter because of a train led by Rahzar and Tiger Claw. Donnie manages to throw Rahzar off thet rain but the werewolf resists thanks to his claws, only to become vulnerable to one of April's telekinetic blasts, which throws him out of the fight. Tiger Claw then gets hit by another train when Raph is saved by Leo. Fishface changes the direction and the group escapes right in time before the train derails and crashes. They join Karai, as she got free of her own restraints thanks to her shape-shifting powers, and says Shredder is unstoppable with his kind of power. April manages to sense Splinter with her Aeon crystal, but Elite Foot-Bots appear to stop them from reaching Splinter. They manage to destroy the robots and track Splinter to the under-city where Splinter fought The Rat King. They find Shredder beating Splinter but more Elite Foot-Bots block them again. Splinter throws a kunai and it hits the explosives. Shredder tries to jump to safety but Splinter manages to grab him so it looks like both of them are going to fall to their deaths. The group can't believe Splinter is gone but Donatello states that the drop is at least 1000 feet down, a fall that Splinter couldn't survive. Karai says they have to keep going for their father and sensei. However, the doors that they locked are blown open with Bebop, Rocksteady, and more Elite Foot-Bots ready to face them.
April is almost sure that Splinter is unconscious from falling into the abyss with Shredder. She and the group retreat back to their lair due to Elite Foot-Bots firing upon them, along with Bebop and Rocksteady. She texted Casey to help them find Splinter and even though she thinks she's lost her mental connection with her Sensei, she doesn't give up hope like Michelangelo. As she, Leo and Karai watch Shredder and his goons, Casey, Raph, Mikey, and Donnie look for Splinter in the under-city. Tiger Claw appears as he was ordered to bring Leonardo and Karai to Shredder and destroy April. April got punched by Tiger Claw, but Karai helps her friend and gets rid of the tiger by throwing him off the roof using her serpent form. She and Karai help Leo fight Shredder, April using her Aeon crystal to throw stuff at Shredder and she even saves Karai from getting crushed to death by a truck that Shredder threw and caught using her telekinesis. After some struggling, she soon manages to gain enough control over the tanker thanks to her Soul Star crystal from the Aeons, causing her eyes to glow blue and smile malevolently, and she manages to throw the truck back to Shredder, but the effort costed her a lot of power as she falls to her knees in exhaustion from it. Karai manages to beg Shredder to not kill Leo using some of her innocent personality, but then punches Shredder's heart once he lets his guard down, which makes him barf mutagen and become so weak, he retreats as he needs more. April and Karai have to help bring Leo back to the lair, allowing Shredder to escape with Tiger Claw, and Karai says next time they'll destroy Shredder. Master Splinter was then rescued by Donnie and Mikey.
April soon finds herself being possessed by the spirit of an ancient Aeon elder by the name of Za-Naron due to her obsession over her Aeon crystal and how it has been helping her with her psychic powers, causing her to suffer memory blackouts and amnesia as a result.
When Za-Naron takes full control of her, she is forced to do Za-Naron's bidding with wanting to purge New York City of evil, such as easily overpowering Tiger Claw, Rahzar, and Fishface, and even saving an old woman from being mugged by Hun and the Purple Dragons.
All the time, April seems unable to fight off Za-Naron's influence, until Donatello tries to help her. April can only apologize to Donnie before Za-Naron takes control of her and scatters Donnie's molecules as punishment for interfering with her plans, but when Za-Naron attempts to do the same to Raphael later when she seems to be in full control of April now, April's memories of Donnie and her guilt of what she did to him earlier gives her the will and strength to fight back and regain control long enough to, at Leonardo's urging, tear the crystal from her neck and shatter it on the street. This causes Za-Naron to be exorcised from April and assume a physical form again as the corrupted form of the Aeons, only for April to silence Za-Naron once and for all by delivering a fatal blow to Za-Naron with her tanto blade in revenge for everything Za-Naron put her through. Afterwards, April is still devastated by what happened to Donnie, but using the shattered remains of her crystal, along with her psychic powers, she is able to collect all of his scattered molecules and restore him to normal.
Waking up back at the lair, Splinter is pleased April was able to literally destroy her demons, and even though she no longer can rely on the Aeons' power to help her, her psychic powers have improved greatly to the point that she no longer needs their aid anymore, as she can handle her psychic powers on her own, and is proud that something good came out of all this after all.
April is at the lair when Casey and Raphael return to report on what happened at the museum, along with the encounter with Alopex, and upon discovering Casey has been cursed by the Cursed Blades of Vengeance, they attempt to go after Alopex to either destroy the blades or transfer the curse to her. At one point when they confront her, April manages to subdue Alopex by holding her in the air with her psychic powers and immobilize her. At that point, Alopex confesses to Tiger Claw being her brother she wants revenge on for ruining her life. When the Turtles offer to help, Alopex manages to draw a kunai in her toes and fling it at April. April dodges, but it forces her to release Alopex, who takes off to find Tiger Claw again before April can recover to subdue her again. After they rescue her from a M.O.U.S.E.R.S. trap Tiger Claw set up for her, Alopex agrees to help free Casey from the curse. April manages to gain possession of one of Tiger Claw's ice blasters, and uses it to freeze the Cursed Blades, rendering them brittle enough to shatter on either a brick wall, as what happened to one of them, or on the concrete of the street, as Casey did with the other one. With Casey free of the curse, April and the others watch as Alopex decides to spare Tiger Claw since he's the only family she has left, but Tiger Claw refuses to simply let his sister walk away and attempts to shoot her in the back, but Alopex dodges, and to the shock of the Turtles, April, and Casey, she slices his gun hand off, warning him that next time, it will be his life rather than another limb like his hand and tail before she departs. April and the others decide to let Tiger Claw, Bebop, and Rocksteady go as the latter two pick Tiger Claw up and carry him away, while they return to the lair, hoping that they might run into Alopex again in the future now that she's proven she's on their side.
April and the rest of the team are enjoying themselves in the lair, when they decide to go have a party with the Mutanimals, especially considering that Karai and Shinigami were taking refuge with them since their old lair was no longer safe with Super Shredder still out there. However, when they arrive, they find the Mutanimals' hideout in flames following an attack by the Super Shredder. Karai nearly dies, but Leo is able to resuscitate her, to both Splinter and Shinigami's relief. Hearing the New York Police Department and New York Fire Department approaching, and finding two trails leading away from the scene, Splinter has April come with him, Raph, Slash, and Casey with following the first trail, while the other Turtles and Leatherhead follow the second trail. The first trail leads them to the Wolf Hotel, where they find the Super Shredder waiting for them. During the fight that follows, April is wounded on the shoulder, despite putting up a good fight with her psychic powers, and is forced to call Leo and the others, warning them of the situation with her and Splinter. At first, Splinter looks to have beaten Super Shredder after tripping him over the edge of the roof, but as April and Raph breathe a sign of relief and triumph, Super Shredder recovers and, to their horror, stabs Splinter through the chest, fatally wounding him, before throwing his body from the rooftop. Enraged, April calmly uses her psychic powers to blast Shredder off the roof and into a garbage truck below, hopefully killing him as Casey activates the crusher. However, the damage is done, and April and Casey sadly join the Turtles with departing with Splinter's corpse to lay him to rest, unaware the Super Shredder survived.
After she, her father, the Turtles, and many of their allies pay their final respects to Master Splinter at his grave on April's family's farm upstate, April, Casey, and the Turtles prepare to confront Super Shredder and end his threat for good and avenge Master Splinter's murder by Super Shredder's hands.
After dealing with all of his defenses, including his mutant henchmen, with Tiger Claw being the last one, April and Casey are separated from the Turtles by Super Shredder and some Molotov Cocktails. April is able to use her psychic powers to save Raph, Donnie, and Mikey when they are thrown off the roof, then wonders about Leo as the fire consumes Shredder's hideout, before Leo appears with the mutated Kuro Kabuto, declaring Super Shredder is gone for good.
With Super Shredder dead, April and the others return to New York, preparing for whatever could fill the void left behind by Super Shredder, but knowing Splinter is still watching over them from the afterlife.
When April discovers Raphael and Casey return from patrol looking a lot worse for the wear, they soon find themselves trying to stop the Foot Cultists from giving Tiger Claw the Scroll of the Demodragon. They fail, and Tiger Claw is able to summon Kavaxas from the Netherworld to serve him and force the Turtles, April, and Casey into retreat.
After learning that Karai and Shinigami are having trouble keeping control of their Foot Ninja due to the return of senior member Hattori Tatsu. With the aid of April, Casey, and the Turtles, they try to beat Tatsu to the mutated Kuro Kabuto since controlling it means control of the Foot Clan, but in the end, Shinigami and Casey are badly injured and need to be hospitalized, Tatsu had his soul drained by Kavaxas, and Tiger Claw gets the Kabuto, but Karai manages to regain control of her Foot Ninja.
Word soon comes that Don Vizioso is in possession of Shredder's heart, the last piece Kavaxas needs to resurrect him. After an attempt by Leo and Donnie to get the heart at Vizioso's restaurant fails due to Donnie's own personal vendetta against Vizioso allowing him to escape to his secondary hideout at the dilapidated hotel, April goes there with Karai, Mikey, and Raphael to try and cover for Leo and Donnie while they go after the heart again. During the scuffle, April gains possession of the Seal of the Ancients that Tiger Claw uses to control Kavaxas, but doesn't have time to ponder over how it works before it falls back into Tiger Claw's hands, while Donnie's lust for revenge results in where while Vizioso and his Mafiosi are arrested by the NYPD, Tiger Claw and Kavaxas escape with the heart, meaning Shredder's revival is inevitable.
In a desperate bid to stop the resurrection of the Shredder, the Turtles, April, and a recovered Casey attack Tiger Claw's lair, but are soon forced to withdraw after facing the resurrected zombie Shredder and Donnie getting the info he needed on Kavaxas. Soon, when Kavaxas launches his invasion of the surface world by unleashing the spirits of the Netherworld on NYC, April, Casey, Raph, and Donnie deal with the ghosts while Leo, Mikey, Karai, and Leatherhead head back to deal with Kavaxas. During the fight, they are horrified to see the spirits of Tatsu and Ho-Chan appear, but are shocked and amazed when Master Splinter also appears to protect them from Ho-Chan while they send Tatsu back to the afterlife. Once Mikey has forced Kavaxas into calling off his invasion and Shredder personally condemns Kavaxas back to the Netherworld for good, April joins Karai, the Turtles, Leatherhead, and Casey, in having a final moment to say goodbye to Splinter before he returns to the afterlife. With Tiger Claw having also called a truce between them after what happened with Kavaxas, April suggests that they enjoy the sunset before heading home.
April is enjoyed playing with Donnie while Raphael tries to watch the TV before retiring to his room to sulk. However, when Raphael receives a call for help from Mona Lisa and Sal Commander, April joins the Turtles and Karai in meeting their old friends from their travels with the Fugitoid, learning that the Salamandrians are here for Newtralizer. April joins Karai, Leo, and Donnie with confronting Newtralizer at a power substation, where April is able to weaken him by splashing him with water from a nearby standpipe with her psychic powers. Rejoining Raphael, Mikey, Mona, and Sal Commander, along with Bishop, they soon chase Newtralizer to the Utrom High Council chambers and back to NYC, only for April to watch as Newtralizer disintegrates Mikey, before a vengeful Raphael tries to avenge him, but can't as electromagnetic interference stops him, before April bears witness as Lord Dregg arrives to finally attain his vengeance for all of his past defeats by the Turtles, April, and the Salamandrians.
As Dregg lays siege to NYC, April does her best to fight off the Vreen before they capture Leo and Sal Commander, forcing the rest of them to find shelter and regroup, with April trying to broken peace between Mona and Bishop when Bishop blames her for leading Dregg to Earth while looking for Newtralizer. When Vreen attack their safehouse, they are forced to covertly make their way towards Dregg's ship, watching in horror as the citizens of New York City are taken to the Channel 6 building, where the Vreen have set up a hive, to be cocooned and made prisoners of Dregg. Attacked by Newtralizer again, April is stunned to see Mikey return from his presumed death, now sporting electrical powers similar to Newtralizer, but it doesn't help when Donnie and Karai are taken by the Vreen as well to join Leo and Sal Commander on Dregg's ship. Taking everyone else back to the sewer lair, April organizes a plan to deal with Dregg: While she, Mona, Raphael, and Bishop attack Dregg's ship in the Turtle Mech, aided by the Earth Protection Force, Mikey will slip inside to free Leo and the others. The plan works, despite losing the Turtle Mech in the process, and after Mona and Raphael knock out Dregg via electrocuting him, they discover that Mikey and Sal Commander knocked Newtralizer into the ship's power core, where the energy being released from Newtrazlier threatens to overload the core and destroy the ship. April flees with Leo, Raph, Donnie, Karai, Bishop, and the Salamandrians, while Mikey remains behind to see to the destruction of Newtralizer and Dregg when the ship finally explodes, before transporting himself down to reunite with everyone. April is relieved Mikey made it as well, and once Bishop returns Mikey to normal and takes away his electrical powers, she watches as Mona requests to stay on Earth with the Turtles, and Sal Commander grants her request, offering a comment on Raphael and Mona as the two share an embrace as she, Karai, and Raphael's brothers watch with both pride and amusement.
Powers and Abilities
- Psionics: As a result of her mother being experimented on by the Kraang, April was born a half human and half Kraang mutant with an array of mental abilities. Her mental energy was stated by Kraang Prime to very unique as it is attuned to the universe. At the beginning, April had little control over her power, but throughout the series, she discovered more of and further developed it through special training with Master Splinter, tested by Donnie and the Fugitoid, and through the power of the Aeon crystal.
- Telekinesis: April is able to use her psychic powers to levitate or push back both people and objects on a molecular level. As the series progresses she becomes to lift heavy objects and even use her power in conjunction with her tessenjutsu. Her power also allows her to unleash various telekinetic blasts/bursts that can damage, repel, crush, or destroy targets and create telekinetic force-fields of different sizes and intensities. She can use her telekinesis to levitate and fly, create destructive telekinetic explosions, and generate shock waves of telekinetic force.
- Telepathy: With her psionic abilities April can mentally communicate with others across vast distances, project mind blasts, perceive visions of the future, manipulate pure telepathic energy, release telepathic beams, control track or detect human beings, astral project herself, mentally detect the auras of others, and telepathically manipulate others minds.
- Extrasensory Perception: April possesses an idiosyncratic ability to sense emotions in certain areas (similarly to Splinter), and she can seemingly "see" into the person - or mutant's - 'soul', such as when she recognized a mutant monkey to be the missing Dr. Tyler Rockwell. She can also detect the true emotions of someone, as opposed to one who mimics them or is but a malicious individual.
- Longevity: As a half-Kraang, she possesses a longer lifespan than regular humans by Earth standard.
- Ninjutsu: When Splinter sensed potential within April he decided to train her to be a Kunoichi. In the beginning, her combat skills were sub-par and even struggled to keep up with the Ninja Turtles whenever they free run on rooftops and hold her own against Karai. In Karai's Vendetta, April surprisingly defeated Karai in hand-to-hand combat. In time throughout the series, April's ninjutsu showed improvement. After the better part of a year of fighting alongside the Turtles and Casey on their adventures, she graduates to full Kunoichi of the Hamato Clan and shows better fighting skills. She is able to hide along with Turtles and even mastered The Dragon's Tail technique.
- Tessenjutsu: April was trained by Splinter in the martial art of the Japanese war fan. She is able to use to strike with the blade of the tessen and use it to defend herself, and can throw it with the likeness of the boomerang. She can also use her telekinesis to levitate the tessen and fight from a distance.
- Tantōjutsu: In City at War, April became armed with the Dragon Tantō as her secondary weapon. April is able to wield the tantō in unison with her tessen.
After only other known relative is her aunt, whom she used to live with, until Master Splinter asked her to stay and live in the sewer until Shredder and the Kraang are stopped and quit looking for her.
- Kirby O'Neil: While April shares a close relationship with her father, as her determination to rescue him shows that she cares for him very much. When she was reunited with him, she was very happy but dismayed that he being mind-controlled by the Kraang though relieved after he was freed. Kirby became very protective of her after he was released before he was mutated into a bat like creature. April was devastated at this and cut off her ties with the turtles after she learns it was partially because of them. She worked very hard to find a cure and when it worked, she was greatly overjoyed to have him back to normal. This happiness only lasted briefly as Kirby was again mutated but by the Kraang much to April's dismay. After the turtles and Mutanimals found a way to return all those mutated by the Kraang, April was reunited with her father and hugged him happy he was back
- Mrs. O'Neil (2012 TV series):April's mother, Mrs. O'Neil, is presumably deceased.
- Donatello (2012 TV series): While she is friends with all the Turtles, April seems to have the closest friendship with Donatello. He has a crush on her, but at first she pretends to be either oblivious, or indifferent about it. However, in, , April was upset when Donnie said Karai was a better kunoichi than her, yet, she seemed a little annoyed by Donnie's attempts to flirt with her. In , April had a picture of him covered in flowers and hearts. Also in this episode, when Donnie yelled out, "My sweet princess is alive!", it is possible that she did in fact, hear what he said. She responded, "Let's agree that you did" after he asked if he muted that, so that is another clue that she knows his obvious crush on her; she pretended she didn't hear that so that he wouldn't be embarrassed. And constantly hugging and kissing him throughout the duration of the series, shows that she not only only knows about Donnie's feeling toward her but also returns them, even stating to Donnie in A Foot Too Big, that as far as she's concerned he's not just a mutant, he's HER mutant, before kissing him on his lips. In When Worlds Collide, Part 1, she and Donnie can be seen playing around throwing popcorn at each other, properly behaving like a couple. And the Ice Cream Kitty (music video) ends with the both of them kissing, possibly cementing them as canon.
- The other turtles do care about her, especially Mikey and Leo. When she was upset, Mikey tried to comfort her by offering her a tissue, which she declined. When Leo didn't know what to do about Karai, he went to April for advice. The only one she doesn't seem close to or have a relationship with is Raph, as they rarely have conversations. However, they do seem to have a similar mindset, both warning Leo about Karai. Raph also seems to look after April in a way like all the turtles do, such as when they all opposed her to spying on The Shredder. Her relationship with the turtles broke up in . In this episode, her father turned into a mutant bat because of the turtles, causing April to run away from them and break their relationship temporarily. Their friendship is rekindled in .
- Casey Jones: April was hired to tutor Casey for an extra credit assignment when they first met, the two quickly become friends, much to Donatello's jealousy. He shows admirable fighting skills, especially when he helps April fight Mutagen Man and Foot Soldiers. Later, after he follows Raph into the lair, he learns that April's friends are mutant turtles and is informed about everything that is going on. Casey and April then start hanging out with April stating what a relief it is for her to have somebody who is in on the secret. Throughout the duration of season two, Casey tries to push their friendship further, trying to find out if she's romantically interested in him. But when in Plan 10 their minds and bodies are switched over and he makes good use of the opportunity to check out her body, their dynamic changes, she doesn't trust him that much anymore for breaking her privacy. In Season three Casey remarks that April has grown cold towards him and when he pulls her close in the Spirit Quest episode and exclaims that it will be just him and her together in the farm house while the turtles train, she looks at him with a "keep your hands to yourself!" look on her face. Later in the episode, she is seen exchanging witty banter about kicking his smug smile off his face. From that moment on, they are pretty much brother and sister with her being the older sister figure in his life.
- Splinter: April seems to be on good terms with Splinter, despite knowing little about him. They share the student-teacher relationship like he has with the turtles. When he realized that she has empathy, Splinter decided to teach her to be a kunoichi. She seems to respect and care for him, especially when she was forced to fight him. Since training under him, April has learned much about Splinter's past (including the loss of his wife and daughter), showing that he now trusts her greatly, and he even gave her the weapon that he intended to give to his daughter, which April accepted honorably, showing that their bond as teacher and student has deepened greatly. He has also called her my child. This suggests that he considers April as one of his own (an adoptive child) like the turtles.
- Irma: Irma was April's best friend and a fellow student at Roosevelt High School. She was based on her 1987 cartoon counterpart. Not much was said or known about her. she was introduced in season two of the series. She called her in the episode, . It was revealed in the season "The Invasion, Part 1" that she was actually Kraang Subprime; a male Kraang master spy from Dimension X, that only got close to April so he could find and give the Kraang the location of the turtles lair which was the only component the aliens needed to beginning the invasion. During the attack on the lair, April comments on the situation being missed up, to which Kraang Subprime replies to by saying that he fooled her and the turtles. He also reveals that the Kraang will capture Splinter and the Turtles and hand them over to the shredder and foot clan in the process. However, she is unaware that he survived his supposed death and has returned multiple times where it appears that he has died but somehow survives and always comes back.
- Murakami: seems to be a close friend and mentor to her. They're always protecting each other from danger such as April protecting Murakami from the Purple Dragons, and Murakami with April from Karai. It's likely that he was the one who taught April basic Japanese words and parts of the Japanese culture.
- Timothy: Timothy develops a crush on April after he learns about her from Donnie. He then decides to hunt her down and stalk her. When he finally caught her, he revealed that he considered her to be his only friend since they both have been in situations that involved mutagen and the end results have been horrible as well as the fact that they are both associated with the turtles. It is suggested that Timothy may have developed a crush on April himself
- Karai: Karai is the one of only other girl humans April has come in contact with, who knows about the mutants and aliens, which normal citizens do not. Although it's established that they are enemies, it's shown that of all of the characters they actually have a lot in common. They both lost their mothers (probably at different points in their lives), they speak Japanese, they are both associated and are love interests of the Turtles, both of their biological fathers have been mutated into animals [both of which are mammals-rat and bat], they are both kunoichi and they know martial arts. It is suggested that April dislikes Karai due to the things that the turtles have told April about her, (which means April, much like the others, sees her as nothing but trouble), as well as the fact that Karai used Leo's feelings to divert his attention. Her views on Karai have now changed now that she has found out and accepted that Splinter is her biological father. In "The Manhattan Project, Part 2", April along with the rest of the team find out that Karai is Splinter's biological daughter to which April shows disbelief and refers to her as an evil witch. She then apologizes to Splinter about the remark which she did believe was honest. She also talked to Karai in "The Wrath of Tiger Claw" and defended her when Donnie and Leo found them on a rooftop. She then told the both of them that she believes Karai was about to accept the fact that Splinter is her real father, showing that she trusts Karai now. In "City at War", she forgave Karai who apologized to her along with her friend Shinigami for everything that has happened between them. She shook her hand in the process. However at the end of "Broken Foot", April gave Karai a stern expression on her face which suggest that she still may hold a grudge against her. She seems to have gotten over it though since they fought together against Baxter's insect minions in "The Insecta Trifecta" and Karai saved April from being killed by Tiger Claw in "Darkest Plight" and April saved Karai from being crushed by a truck thrown by Super Shredder in the same episode with her psychic powers.
- Shinigami: Shinigami is another human girl April came into contact with who is Karai's old friend. she didn't like her at first due to Shinigami having superior fighting skills and besting her in two duels. at the end, She forgave her and Karai for everything that has happened between them all.
The Kraang have been April's archenemy from the very beginning of the show. She didn't know why she and her father were kidnapped, and hated them because of it. However, she's now discovered that there's something about her that's different than other humans. It's unknown what the truth behind April and the Kraang is, but it's likely that the Kraang want to use April for their invasion on the Earth. It is revealed in the season finale by Kraang Prime that the Kraang need April because of her mental energy, which is uniquely attuned to the universe, and they need it to synthesize the mutagen, as well as use it to mutate Earth (wiping out all of life in the process) so they can live there and evolve. The Kraang have become obsessed with finding and having April for their plans and perhaps even to themselves. That idea has now changed as they thought it would be amusing to kill her, while collecting her DNA in the process, in The Kraang Conspiracy and trying to exterminate her along with the Turtles and Casey in "Plan 10," "The Invasion," and "Return to New York." This is most likely due to the fact that since the Kraang have somehow perfected the mutagen, they no longer require April for their plans anymore and, much like the Turtles, only see her as a threat and enemy now.
The Shredder has used April as bait to lure out his enemies so he can destroy them. He then handed her over to the Kraang who are her other enemies. It is suggested that April dislikes the Shredder. She also hates him for killing Splinter, hurting her friends and using her and others (like Karai, Leo and her own father) in his sick and twisted plans for revenge. Although April and the Shredder have met on a few occasions, they have had little interaction with each other. In Darkest Plight, April used her Aeon crystal to throw Shredder stuff and a truck against him showing her force to destroy him.
April dislikes the Foot Clan as much as she dislikes the Kraang and Shredder.
Baxter Stockman has used, kidnapped and grabbed April and brought her to his lab. He tied her up above his vat of mutagen and explained his plan to her. During this fight, it is revealed that April is immune to mutagen, explaining why her DNA worked as the catalyst for the Retro-Mutagen.
“I don’t know! I’m flunking trig, my friends are mutants, aliens got my dad, and I LOST MY MOTHER!”- Karai's Vendetta
"You guys wanna speed it up a little?!"- Never Say Xever
"This is it, April. A new start. Just pretend you're a normal girl. Don't talk about alien robots, or mutant dad, and don't even THINK about turtles- WHOA!"- Mutagen Man Unleashed
"It was an accident, and more importantly you're my friends. I don't want to hold a grudge ever again." -Target: April O'Neil
"Not bad for a nobody"- Karai's Vendetta
"You talk too much"-Target: April O'Neil
"Got that from nobody"- Karai's Vendetta
"I still can't believe that evil witch is your daughter. um.... sorry to be so honest".- The Manhattan project part 2
"You wanna do this Karai; fine! but I'm warning you, I've been training with splinter big time and I'm ready to kick your butt"- The Wrath of Tiger Claw
"Oh, well I've been trained in that too"- The Wrath of Tiger Claw
"You're my hero"- Showdown Part 2
"Doubts about the evil leader of the evil ninja clan, really?"
"I believe that she believes you"- The Wrath of Tiger Claw
"Leo, Donnie wait... you have to listen to what she has to say"- The Wrath of Tiger Claw
"I don't know. I always kind of wanted a twin sister." "Wow! Me too! This is actually kinda cool!" - Earth's Last Stand
"It's my crystal. I'm never gonna take it off again for anyone, or anything, ever again..." - Bat in the Belfry
- April's name comes from the Latin "aprīlis", meaning "of the month of the goddess, Venus". April's surname, O'Neil, is of Irish origin; derived from Irish Gaelic, it means "descendant of Niall". Her surname implies that April has family roots in Ireland, making her ethnicity/nationality Irish-American.
- April is called "April-chan" by Mr. Murakami, who she likewise addresses as "Murakami-san".
- In Japanese, April's name would be 四月 (しがつ, shigatsu), meaning "the 4th Moon"; (moon = month and April is the 4th month) or 卯月 (うづき, uzuki), meaning "Moon of the Rabbit". In Katakana, April's name is spelt: アプリル (Apuriru).
- As of the events of "Baxter's Gambit", April is now armed with a tessen, (lit. a "Iron Fan", better known as a Japanese war fan), a weapon that Splinter had one day hoped to give to his daughter, Miwa, who April reminds him of. April will now be focusing her fighting style around the real-life Japanese martial art of Tessenjutsu. The tessen has a sharp edge when spread open, and can also be used as a throwing weapon.
- April is revealed to have Chiroptophobia a fear of bats in "Fungus Humungous" most likely because of what happened in "The Mutation Situation".