Karai

Karai is a member and leader of the Foot Clan Japanese branch, and, following the events of City at War, became the leader of the Foot Clan New York branch. She has proved to have been both an asset and a liability to the TMNT, making her an extremely chaotic character. In the 2003 series she is the adopted daughter of Oroku Saki.

Mirage Comics
Karai was introduced in Teenage Mutant Ninja Turtles Volume 1, during the "City at War" storyline. She came from Japan to New York to unify the warring factions of the Foot Clan that had risen following the death of Oroku Saki. Shredder's Elite Guard forces had been randomly attacking anybody seemingly without reason. Karai offers the Turtles a deal; if they assist in stopping the Elite, she will give them a treaty with the Foot. The Turtles reluctantly agree to the truce, and fight to the top of her skyscraper, taking out the Elite stationed there. When they reach the top, they witness a group of slain Foot Ninja, along with the body of a young girl - Karai's aide and daughter. Karai makes Leonardo swear that they will kill all of the Elite Foot in retribution.

Karai then dons the armor of the fallen Shredder, leading a pack of Foot Ninja. An Elite mistakes her for the real Shredder, and is shocked. Following this is a final confrontation against five Elite Foot. Karai, in the guise of Shredder, demands that they all commit seppuku. Only one weak-willed Elite complied, but the others demanded the identity of The Shredder revealed. After revealing she was not Oroku Saki, Karai threw the helmet at an Elite and a grand battle ensued. When the fight was over, the Turtles and Karai were the only ones left alive, and despite the Turtles' protests that she owed them nothing, she gave her word that the deal would be honored and that she herself would return to Japan to spread her daughter's ashes and begin a journey of amendment.

Karai was not seen again in the comics until Volume 4, in which a band of mysterious warriors from seemingly another dimension had begun giving the Foot trouble. She hires Leonardo as security, and they capture one of the warriors to interrogate. Karai later lies to Leonardo about the Foot possessing books on mystical arts, which Leo can see right through and notes that because Karai is normally an exceptional liar, something was either bothering or manipulating her. This storyline is still on going and has yet to be resolved.

Image Comics
Karai did not appear as herself in the Teenage Mutant Ninja Turtles "Volume 3" by Image comics; however, it was confirmed that she was the character behind the mantle of the enigmatic "Lady Shredder" that appeared in the series' final issue; this was a revelation that was to occur in a later issue, before the series was canceled.

History
Karai was found by Oroku Saki after her parents abandoned her. He took her in as raise her as his own, teaching her bushido. She became his most trusted follower, even trusted to his true identity as Ch'rell and told her that the Utroms were savagely hunting him. When the Utroms fled for New York, Karai remained in charge of the Japanese Foot Clan.

Storyline
Debuting in the show's second season, Karai eventually became one of the series' main non-turtle characters. A woman torn between honor and family, she appears both as an ally and enemy to the turtles; a dichotomy that plays a part in most of her appearances.

When the Purple Dragons, the Mafia, and the Foot were fighting for control of New York after the Shredder's demise, Karai arrives in the city and quickly enlists the aid of the Turtles to stop it, promising an end to the Foot’s vendetta against them in exchange for their assistance. Leonardo, convinced that Karai is honorable despite her legacy, convinces Donatello and Michelangelo to aid Karai. Raphael refuses, although he later recants. Together, Karai and the Turtles eventually retake control of the New York Foot and consequently its underworld. However, the end of the story reveals that Karai had been manipulating the Turtles, and had been working with the not-dead Shredder all along. She shows sadness when Shredder (Chrell) vows to get revenge on the Turtles after she had made a truce with them.

Karai and the Foot reappear in Rogue in the House, Part 1, where a fully-healed Oroku Saki retakes control of the Foot. As his first order of business, he deploys a killer robot (disguised as Splinter) to eliminate the turtles. Realizing that their agreement with the Foot had been retracted, the turtles decide to face the Foot again in their temporary HQ—a ship stationed at the docks. Leonardo, Raphael, and Splinter are taken hostage during their encounter, and Karai is forced to fight Leonardo. Despite Leonardo’s lack of resistance, she proves unwilling to kill him.

Karai’s internal conflict—loyalty to fellow bushido-practitioners the turtles vs. loyalty to her father—is the main thrust of her Season 3 storyline, as she is pulled from both directions to take a side. She manages to stay in the graces of both sides until the Turtles face the Shredder again in the season’s finale, where she stabs Leonardo in the shoulder, damaging his carapace, although she later prevents the Utrom Shredder from killing the Turtles while they are unconscious. Despite her efforts, however, the Shredder is taken prisoner and exiled, Karai and Foot Tech Division Head Dr. Chaplin are sent back to Earth. With her father gone and dead in the eyes of the world, Karai takes over the Foot, as well as the guise of the Shredder. Furious at what she saw as a betrayal by the Turtles, Karai spends the season plotting her revenge against them, first attacking them on the psychic plane via Foot Mystics, and later coordinating and leading an assault against them at their lair, which she believes successful. She later on faces Leo (who was not at the lair at the time of the assault), who defeats her but then departs with the warning to leave his family alone and giving her one last chance for redemption.

Karai next faces the turtles during their attempt to retrieve a Foot artifact, an amulet called the Heart of Tengu. Despite her efforts, she is unsuccessful in stopping them.

Unbeknownst to the Turtles or Agent Bishop who initially charged them with retrieving the artifact, the Heart of Tengu was a mystical artifact that allowed the Foot to control its Elemental Mystics, who are in reality the heralds for a man-demon that had centuries ago terrorized Japan as the Shredder. The destruction of the artifact unleashed a chain of events that resulted in the demon Shredder’s resurrection. His first target is Karai, who “usurped” the Shredder’s name. The Shredder and his heralds make their way to Foot HQ. Despite her efforts and those of the Turtles, who believe her the key to stopping him, he bests Karai in battle, seriously injuring her.

Rescued by the turtles, Karai heals and, recognizing the threat the demon Shredder poses and her inability to stop it by herself, agrees to a "temporary" alliance with her enemies.

It is soon learned that because she shares The Shredder's mantle, Karai has the latent psychic ability to lower Shredder's defenses through a shared link. This allows the Turtles an advantage in their final conflict with the demon. By being instrumental in this way, Karai helps pave the way for her namesake's destruction. Doctor Chaplin, the young head of the Foot's scientific division, helped the Turtles co-ordinate their battles against the demon. After the battle Karai promises Chaplin that she is going to worry more about the immediate future, as they depart the battlefield, hand in hand.

The Lost Episodes
Karai was unable to prevent the forces of The Tengu Shredder from demolishing her New York base of operations and humbling her in battle. She was eventually rescued by the Turtles, and taken back to April O'Neil's apartment, where she was tended to by the Turtles' female friend. Dr. Chaplin followed her trail, and was brought to her after being caught snooping around the building. Karai seemed warmly jubilant with his arrival

Fast Forward
Karai appeared in one episode of the Fast Forward television series, in the episode "The Journal". The TMNT find a book said to be written by Casey and April detailing what occurred following the Turtles' return to the present. Leonardo goes for further training with the Ninja Tribunal, and is surprised to find that Karai is doing the same. After some time, Leonardo has a vision that someone will betray the Tribunal, and given their history, he suspects Karai. He later spies on Karai and witnesses her talking to The Shredder's helmet, and believes his suspicions are confirmed. Leonardo attacks Karai, and it is revealed that she had brought the helmet for a ritual where she would cast off Oroku Saki's influence forever. The Tribunal note that Leonardo has fulfilled his own prophecy - that he is the traitor - and is exiled from the training grounds. As the events in this book are written by Splinter and Cody, it is unlikely anything of the sort occurred (or will occur).

Back To The Sewer
Karai made her first appearance in the Back to the Sewers storyline in the episode Something Wicked. Here, she was seen in a brief flashback with Ch'rell, the Utrom Shredder. Karai next appeared in the season finale, "Wedding Bells and Bytes", having been invited to attend the wedding of April O'Neil and Casey Jones. It appeared as if she and The Turtles had resolved their difficulties off-camera, and she arrived at the ceremoney with Doctor Chaplin by her side. She and Chaplin later assisted the Turtles in fending off the onslaught of Cyber-Shredder and The Foot Clan. Though she had no lines, it was apparent that she had moved on with her life and was no longer involved with the Foot.

2007 Film
In the film, Karai leads the Foot Clan after the Shredder's defeat, acting as mercenaries.

She was hired by Winters to be "the eyes and ears" of the city, though she showed anger later when she found the truth of his unexpected order to hunt down monsters. She briefly fought with Leonardo, rejecting his offer to help them, implying that she is aware of his role in the past. This is supported by her line to the Turtles, 'you are every bit as warriors I was informed you were' after the defeat of the Stone Generals. Karai also seemed to have had prior knowledge about Leonardo; before their brief confrontation Karai proclaimed 'You!' as she faced him. Karai also engages in battle with April O'Neil while the Foot battles the Turtles and their allies.

When the Stone Generals offered the Foot a chance to join them in world conquest, Karai refused, saying that they will honor their contract to Winters. She led her ninja in retrieving the last of the monsters (aided by April and Casey). Karai parted ways with the Turtles peacefully, after giving a cryptic last word that "savor your victory tonight, for soon we will have further business together; the kind that involves familiar faces from your past", perhaps hinting the Shredder's return.

She was described in her toy bio as being 'the Shredder's daughter', recalling her character of the 2003 series. However, no indication of this was given in the actual film other than her attacking Leonardo.

TMNT: Tournament Fighters
Karai is the final boss in the Genesis and Super Nintendo versions of Teenage Mutant Ninja Turtles: Tournament Fighters (also a playable secret character in the latter version).

TMNT2: Battle Nexus
Karai is an in game boss and an unlockable character in the console version of Teenage Mutant Ninja Turtles 2: Battle Nexus.

TMNT Smash-Up
Karai will be a playable character in Teenage Mutant Ninja Turtles Smash-Up. Her appearance is that of the 2007 movie.