Some TMNT stuff really isn't for little kids.
Oroku Karai appears in IDW Publishing's ongoing, re-imagined Teenage Mutant Ninja Turtles reboot series by Kevin Eastman, Tom Waltz and Dan Duncan (later also Andy Kuhn and Mateus Santolouco). Duncan posted a character design sketch of her on his Deviantart account, writing that he prefers to "refer to her as Shredder's girlfriend." Waltz said about the future issues: "I can't say much yet other than Karai has played a pivotal role in the events leading to Saki's return."
Karai is the daughter of Oroku Yori and a direct descendant of Oroku Saki and Kitsune, about three hundred years after his supposed death in feudal Japan. As a young girl, Karai found the Ashi no Himitsu and discovered the warrior history of the Foot Clan, using it to train herself in martial arts and ninjutsu. She began living a double life as both a respectable Japanese daughter and as a fierce ninja-in-training.
As a teenager, she was visited in a dream by Oroku Saki, who urged her to resurrect him. Karai promised to do so, but felt she had to first rebuild the Foot Clan into a clan of ninja warriors once more. She enlisted and trained new ninja, eventually taking leadership from her father and disposing of the lawyers and businessmen who had infested the clan. After this, she kept her promise by using her blood to resurrect Saki, and handed over leadership of the clan to him.
Following Saki's resurrection, she remained as chunin (second-in-command) of the Foot, showing unconditional loyalty to her ancestor (whom she calls her "grandfather") and the clan. Despite this loyalty, the Shredder often denigrated her abilities and declared her unfit to lead the Foot.
She first came into contact with the Turtles when the Foot abducted Splinter from StockGen, and she attempted to recruit him into the clan. When the Turtles came to rescue their father, she fought Leonardo and was quickly defeated.
Shortly thereafter, the Shredder declared his intention of selecting another individual as his chunin, and ordered Karai to bring him Leonardo. This decision angered Karai greatly, leading her to lash out at Leonardo during their next conflicts. However, she obeyed her ancestor's orders, arranging for the kidnapping of Casey Jones and the subsequent abduction of Leonardo.
Her jealousy only increased when Leonardo was brainwashed into a faithful follower of Shredder, as he openly showed his contempt for her and relegated her to a tertiary role with no power. He succeeded in provoking her into a fight at one point, but Karai allowed him to win, knowing that her grandfather would kill her if she killed his chosen chunin.
Instead she chose to undermine Leonardo by mutating Bebop and Rocksteady in order to show her superior loyalty and abilities to Shredder, which nearly led to the Turtles' defeat as they reclaimed their lost brother. Shredder then revealed that the selection of Leonardo had been partly a test to ascertain her true abilities as a leader, and reinstated her as his chunin.
Karai remained in New York during Shredder's attack on Burnow Island, and was wary of Donatello's involvement in the endeavor. When Shredder was presumed dead, she assumed control of the Foot Clan and decreed that they would purge themselves of outside influences such as Professor Patrick Miller, and used Foot assassins to kill such outsiders. Even when Shredder returned, she insisted that the Foot needed no one but itself, and opposed the temporary alliance with Baxter Stockman. She was even more dismayed when she realized that Stockman would be attacking on behalf of Shredder with flyborgs and M.O.U.S.E.R.s, rather than with honorable combat.
She took a squad of Foot ninja to destroy the flyborgs and M.O.U.S.E.R.s, and intended to give the Turtles and Splinter a warrior's death. However, Splinter informed her that the Foot Clan had a method of honorably deciding irreconcilable conflicts between clans, and Karai escorted the mutants to the Foot Clan headquarters in order to issue an official challenge.
She witnessed her grandfather and his four mutants fighting in the Gauntlet, in which all were defeated. Before his death, Shredder expressed his pride in her abilities and strength. After Splinter beheaded him, Karai stated that she had seen true leadership in Splinter, and offered him leadership of the Foot Clan. Rather than remaining, she left for Japan with Bludgeon, Koya and her mentor Toshiro.
Without the Foot Clan, she remained somewhat aimless during her time in Tokyo, until a clash with a young yakuza woman named Natsu left her injured and insulted. The woman's grandfather Hayashi Toru appealed to Karai to delay her vengeance, and instead fetch an ancient legendary sword for him. This quest intrigued Karai, who agreed to find the sword and embarked on a supernatural journey into the Japanese countryside to find the Kira no Ken.
However, she soon learned from Natsu and Toshiro that the quest had been merely a ploy by Hayashi to kill her. In retaliation, she broke into his compound, killed him with the sword, and took control of his many businesses. Some weeks later, she disposed of several other yakuza bosses in order to solidify her power, vowing to return to New York when she had formed a new power base for herself.
She reappeared at the conclusion of TMNT: Bebop & Rocksteady Hit the Road, declaring her intention to conquer New York and recruiting the two to help her. She later met with Leonardo, and the two planned together to convince Splinter to peacefully hand over leadership of the Foot Clan to Karai.
In issue #91, Kitsune reveals that it is Karai's genealogical descent from the Dragon (Kitsune's father) that enables Karai to wield the Kira no Ken. Though it was implied as long ago as The Secret History of the Foot Clan that Kitsune was the matriarch of Oroku Saki's heirs as the couple did have children together, this is the first concrete confirmation that Karai is Kitsune's direct descendant. Karai also refers to Kitsune as "Grandmother" in the same way she referred to Saki as "Grandfather."
In issue #92, Splinter and Karai negotiate to hand over leadership of the Foot Clan back to the latter. They come to an agreement on all points of negotiation except one: The fate of the children of Saint Robert's Orphanage. As previously decided in the Michelangelo Macro-Series issue, Splinter makes it non-negotiable that the children will never be forcibly conscripted into the Foot Clan. Karai finds this unacceptable, insisting that children who have seen so much of the inner workings of the Foot Clan must all either become loyal Foot Ninja or be put to death. When Splinter rejects this, negotiations break down and Karai challenges Splinter to another Gauntlet, which he declines as he will no longer allow the deaths of innocents under his command. Karai makes a formal declaration of war against Splinter and his forces. Splinter then recognizes Karai's new red sword as the Kira no Ken, describing it as a tool of death that will bring only sadness, and he pleads with Karai not grasp too tightly to remnants of a past that cause destruction in the present, a lesson Splinter himself has learnt all too well. Karai leaves Foot Headquarters, vowing to cause death and destruction like Splinter has never known before.
Karai then heads to the home of Antonio Puzorelli, offering him eternal freedom from tribute if he joins the Oroku Clan in destroying Splinter. She also met with Jennika, attempting to sway the chunin's loyalties from Splinter to herself. But after Jennika reaffirms her loyalty to Splinter, Karai stabs her before departing.
- In 2014, Waltz said Karai is one of his favorite characters: "Such a cool character – tough, smart, mysterious... you just never know what she'll do next."