Leonardo (IDW)

Past Life
In ancient Japan, and  had four sons. Unfortunately, due to Yoshi's standing against the corrupt leader, Saki targeted Yoshi and his family's lives. Tang Shen was slain trying to protect her four young sons - a memory that Leonardo still possesses - and begged her husband to take them far away and protect them. Eleven years later, the four boys were murdered by Saki's men before their father's eyes, moments before he himself was killed.

Centuries later, the sons of Yoshi were reincarnated as Turtles that were being used as test subjects for scientific experiments, and Yoshi himself was a rat in the same lab. During their tenure, a band of ninja attempted to steal an experimental, and the five of them, along with an alley cat, ended up doused with the substance.

Change is Constant
Fifteen months after the incident that endowed mutated Leo and his family along with being separated from. During those fifteen months Leo and his two remaining brothers and  were trained in ninjutsu and other martial arts by Splinter in order to survive New York and also find their missing brother. After Leo and his brothers completed their training they began their search throughout the city to Raphael. During their search they encountered Old Hob the mutated version alley cat that attacked them months ago. Hob attacked the turtles with a gang of hired thugs in an attempt to bring Splinter to Dr. in order to create a perfected mutagen. During their encounter Leo and his family were able to take out the thugs easily leading to Hob joining the fray. Leo's sensei was able to defeat the alley cat leading him to flee along with swear vengeance on Leo and his family. While recouping from Leo's brother see the situation of finding Raph as hopeless while Leonardo asks Master Splinter for reassurance that they'll find their lost brother, Raphael. Splinter tells him the reassurance he seeks must be within him already, as he has not yet given up the search. While in the sewers Leo and his brother train while Splinter scolds them for celebrating their victory over Hob prematurely. After training Leo and the others head out and are eventually reunited with Raphael when him and his are surrounded by Hob and his gang. After defeating Hob's gang Leo returns Raphael to Splinter where celebrates their reunion by giving Leo and his brothers their trademark colored masks.

Enemies Old, Enemies New
While patrolling the city's rooftops at night Leo and his brothers see two ninjas on the run. During the chase tensions flare between the Turtles while Leo tries to keep them focused on their mission. During the chase Leo and the turtles found that ninja were chasing a Frenchman who used parkour to kill one of his pursuers. After Raphael attempts to rush in Leo and the others witness the man die and the leave the warning that war is coming. Leonardo and his brothers later return to the sewers to report to Splinter the event that had occurred. After hearing from Splinter about the Foot Clan they learn that a great war involving a rivalry from their past is to come. After learning this Leo and Donatello get into an argument about the matter truth of their past lives until the two brothers and Splinter are attacked by Baxter's M.O.U.S.E.R robots. They managed to destroy dozens of the robots but more keep attacking and they have to fall back and regroup. Before they're able to, Hob who was controlling the robots steps out of the shadows, revealing himself to be responsible for the attack. He orders the robots to begin attacking the walls, causing a cave-in above the Leo, Donnie, and Splinter. Despite this Leonardo is last seen fighting the remaining robots while the others were knocked out and Michelangelo and Raphael return from the surface. After teaming up with Raph and Mikey to defeat the remaining robots and Hob Leonardo realized that Master Splinter is missing. Upon learning he's missing the turtles quickly planned to find Splinter and rescue him. While planning to find Splinter Leo and the other turtles are soon reunited with April after Casey brought her to the sewers to meet Leo and the others.

Shadows of the Past
After reuniting April Leonardo and his brothers quickly come up with a plan to break into Stockgen to rescue their father. The turtles plan to break into the facility by using a repurposed M.O.U.S.E.R robot. to attack the radio transmitter in the security guard's office. With their communication system disabled, the security personnel leaves their posts to investigate, allowing the Turtles to slip in unnoticed. While in the facility Leonardo and his brothers face of against a deadlier M.O.U.S.E.R and eventually meeting not only  Old Hob who is passed out, but also a scientist named. Leonardo interrogates Chet to find out where Splinter is and find out he is being held by the Foot Clan.After breaking into Stockgen to find Splinter has been taken again, their spirits are low and their tensions are high. Leonardo says they're up against the Foot, that it is their past life leading them to fight their old foe. Donatello tells him that's garbage, and the whole idea that they're four boys from Feudal Japan reincarnated is ludicrous. Donatello is convinced that all of their conflicts are centered in the here-and-now, modern-day affairs related to their escape from Stockgen and subsequent mutation. The Turtles begin arguing emphatically until Michelangelo breaks them up, reminding them that they have no home now and need to find a place to go. While regrouping at an old thrift store called "Second Time Around" that was owned by April's family Leonardo, his brothers, along April, and Casey plan their next move while a spies on them. Leonardo, Donatello, and Raphael talk about what they should do to find Splinter Leonardo and the others find themselves in a fight with Angel and her gang the. After clearing up the situation Leonardo and the others learn from her about the location of the Foot. Leo leads his brothers, Casey Jones to break into the Foot Clan's lair to stop Shredder from torturing Splinter. A huge battle ensues, with Casey and the Turtles battling the Shredder, Karai, Alopex and a legion of Foot ninjas. Donatello finds Splinter and tries to get him to safety, but Shredder zeroes in on him. As Shredder is about to attack Leonardo jumps in and parries the blow. Splinter tells Leonardo that their only hope is to work together and fight as one. The Shredder tells the Turtles that their master is beaten and if they have any hope of surviving they should join the Foot Clan. As Donatello, Michelangelo, and Raphael fight Shredder, Casey and Leonardo continue trying to get Splinter out safely. The large Foot ninja Splinter fought earlier is about to attack them when he's knocked out by Angel. She tells Casey that this may not be Purple Dragon business, but she owes Casey. Casey and Angel get Splinter outside. The Turtles take on Shredder together and are finally able to defeat him and return home.

Sins of the Father
While recovering the previous battle Leo and turtles are currently staying at April's apartment as their temporary base. While their Leo was playing a game with his brothers when Cassie came in beaten up from another one his fathers beatings. Leo witness Raphael storm off to Cassie's house to teach his dad a lesson while his father Splinter follows to keep Raphael from going to far. Meanwhile at the Foot Clan's lair Leonardo had caught the attention of the Shredder as Oroku Saki discussed with Karai about Hamato Yoshi's (Splinter in his former life) oldest boy, even at so young an age, displayed all the attributes of a true warrior. Karai asks why she mentions him. Saki tells her it is because that boy has not changed in his new life, and he wants her to bring him that boy – Leonardo, leader of the ninja turtles, to be made into his second-in-command.

Blood Brothers
Sometime after Leo and his brothers reunited with Splinter, the Turtles are seen investigating the scene of an attack. Witnesses report a "big, green lizard" and "deadly force authorized". Leonardo says they need to hurry up and found another underground hideout before they get blamed for the attacks. The Turtles make their way to check out a potential hideout found by Donatello and April, on the way the Turtles talk about Splinter's "Destroy Shredder Manifesto", wherein he said while the Shredder lives they will never have peace. While Leo and his brothers are on their way to check out the new hideout they stop to interrupt a mugging, and they are twice referred to as "Slash monsters", emphasizing the need for them to find a safer hideout to avoid a case of mistaken identity. As they flee scene after disposing of the thugs, Slash arrives at the scene, hot on their trail. He catches a glimpse of them and tears of part of one of the thugs' shirts, fashioning himself a black bandana like the other Turtles'. The Turtles arrive at the potential hideout, an abandoned church with a nuclear fallout shelter underneath. The Turtles are checking out the dark bunker with flashlights and decide the place is perfect when Slash arrives. Once inside he attacks. He eventually knocks out Donatello and Raphael and is about to take out Leonardo. While the Turtles are on their way to check out the new hideout they stop to interrupt a mugging, and they are twice referred to as "Slash monsters", emphasizing the need for them to find a safer hideout to avoid a case of mistaken identity. As they flee scene after disposing of the thugs, Slash arrives at the scene, hot on their trail. He catches a glimpse of them and tears of part of one of the thugs' shirts, fashioning himself a black bandana like the other Turtles'. The Turtles arrive at the potential hideout, an abandoned church with a nuclear fallout shelter underneath. The Turtles are checking out the dark bunker with flashlights and decide the place is perfect when Slash arrives. Once inside he attacks. He eventually knocks out Donatello and Raphael and is about to take out Leonardo. During the fight Leonardo listens to Donatello tell him and his other two brothers that Slash was psychologically programmed to hunt down and kill them, and will continue to try to do so until he's dead, meaning they have to kill him. While Raphael agrees with Donatello, while Leonardo and Mikey want to try and end things peacefully if they can. Leonardo attempts to put Slash in a sleeper hold while the others wear him down. They appear to be near victory when Slash throws them all off, his stamina nowhere near out. Slash tells them to keep it coming. Slash begins to attack again but Leonardo hits him with a shuriken and tells him it has to stop. Outside, April and Casey arrive and enter the church. Inside, Leonardo attempts to talk Slash out of hunting them, to no avail. Slash lunges at Leonardo, who, distracted by April and Casey's arrival, accidentally stabs Slash in the neck with one of his swords. Slash is seemingly mortally injured, and falls into the sewer.

The next day, everyone is helping clean the dirty bunker to make it more suitable to live in. Michelangelo has gone to pick up some pizza and Leonardo meditates downstairs. When Michelangelo arrives at the pizza shop, he finds a note from Woody, saying their friendship has to end due to the baggage that Mikey brings, deeply upsetting him. Downstairs, Leonardo sits staring at the sewer where Slash fell in, preoccupied with guilt from killing him.

Krang War
Leonardo was present during Master Splinter's family meeting and starts off by acknowledging the setbacks they have recently faced. They have all been tested and shown their courage and skill, and must use this as momentum to go forward, and form a proactive plan. He says that although their enemies benefit from alliances, they benefit from being a true family. They must act, and April knows where they should start.Later Leonardo, his brothers, and Casey are later seen spying on April's lunch with Chet Allen. While she talks with him to find out what is really going on in Stock Tech. This conversation ends when Commander Dak and his fellow Neutrino rebels bust in to claim Chet. When this happens Leonardo and his brothers jump in any information she can about what's really going on at Stockgen. Chet warns her that she could endanger herself by asking too many questions, when all of a sudden Commander Dask and his commandos materialize, saying they're there to rescue him, as Chet is in reality Professor Honeycutt, the Fuitoid, in disguise. Casey and the Turtles immediately spring into action to protect April. Casey manages to get April to safety but the Neutrinos attack to protect Professor Honeycutt. The Neutrinos are teleported back to Planet Neutrino but the Turtles are taken with them, brought back into the midst of a battle between the NRF and Krang's stone soldiers. The Turtles have been teleported back with the Neutrino commandos to the NRF command center, which is under attack. The Neutrinos immediately begin firing back against Krang's troops, but the Turtles demand some answers first. The Neutrinos tell them they'll get all the information they want but first they have to make sure they survive Krang's attack. Working together, the Neutrinos and the Turtles defeat Krang's troops and get to safety. Leonardo and Commander Dask devise a plan to rescue the King and Queen by initiating a distraction so that the Turtles may slip into the castle where they're being held unseen. Leonardo and Michelangelo are preparing to infiltrate the Neutrino royal castle where the King and Queen are being held with Commander Dask and Kala when Princess Trib informs them she will be coming as well and there's no convincing her otherwise. Meanwhile, Raphael and Zak prepare to lead the frontal assault to serve as a distraction. Once the attack begins, Krang immediately orders his forces to lead a counter-attack. With the distraction underway, Leonardo, Michelangelo, and the Neutrinos infiltrate Krang's base. While Raphael and Zak continue leading the frontal assault, while Leonardo, Michelangelo and the Neutrinos have reached the room where the King and Queen are being held, guarded by General Krang. Leonardo manages to slice off one of Krang's robotic suit's arms. Krang recognizes the Turtles as the ones that were stolen from Stockgen. . The NRF forces in the attack are under heavy fire and the situation looks grim. Honeycutt and Donatello have finished the END missle and launch it towards the battlefield, following it to ensure it isn't struck down. The Utrom mecha is about to swat it down when Raphael takes it out with a rocket launcher, allowing the END missle to detonate and disable all of Krang's troops' weapons. In the Neutrino royal castle there is a standoff between Krang, his forces, the Turtles and the NRF. Honeycutt arrives and says he has neutralized Krang's entire army, effectively winning the battle. However, Krang reveals that his weapons operate on a different frequency, meaning he still has lethal firepower. Honeycutt gives himself up to spare the others, and Krang teleports back to Burnow Island with him. The Neutrinos thank the Turtles for their help. Leo and his brothers were later teleported back from Dimension X. Everyone is glad to be reunited.

Trivia

 * It is revealed in issue #32, that Leo is right-handed.
 * He named his swords Musashi and Kamiizumi.

Gallery
Leonardo (IDW)/Gallery

Leonardo