Some TMNT stuff was always meant for grownups.
Kujikiri the Headhunter is a female assassin that appeared in Big Bang Comics #10. She is the quarry of the vigilante Galahad, although he is unaware of her gender. She is the sister of Go-Komodo and mother of Pimiko.
When he first encounters her, she is in bed with a man that he mistakes for Headhunter, but when she reveals herself, it is made known that the man is Oroku Saki. When Saki steps forward in his full Shredder armor and orders his Foot Soldiers to kill the pair. Galahad and Headhunter call a truce and begin battling the Foot Clan. Galahad fights his way to the Shredder and explains that he’s only after Headhunter. Shredder refuses to give her up, saying they have unfinished business. Galahad then takes three arrows to the back and a bo staff to the head. As Galahad falls face first to the ground, Headhunter berates him for not taking the Shredder down when he had the chance and angrily calls their truce off. As Headhunter escapes, Shredder orders two of his Foot Soldiers to finish off Galahad while the rest go after Headhunter and bring her back alive. The Foot Soldiers decide to do a half-assed job and just dump Galahad’s body into the sewers.
Later after Galahad encounters Shredder and we learn that one of Shredder's Foot soldiers, was displeased with Shredder’s leadership, hired Headhunter to deal with him. Shredder, in turn, dealt with them. Due Galahad's intervention this lead Shredder deciding to let her go as a way to repay his debt to Galahad. Later Galahad finds Headhunter in an interrogation room, badly beaten and with a sai sticking through her hand. Galahad arrests her and is about to bring her to a prison hospital when she offers "a deal". Galahad refuses anything she has to offer, so Headhunter responds by knocking him out. Giving him a kiss, she promises to come back for him some day after she’s healed from her interrogation.
It is revealed by Go Komodo in TMNT: Urban Legends #24 that one of these trysts resulted in the pregnancy of a child, the eventual daughter of the Saki legacy Pimiko. He also states that the Headhunter was his sister Kujikiri. Pimiko was raised by Komodo, never the wiser of her mother's identity.
- Although there was nothing stated in Big Bang Comics #10, Gary Carlson mentioned on his blog that his intention was to have Headhunter turn out to be Pimiko's mother. This plot thread is integrated in Urban Legends #24
- Her real name, Kujikiri is more likely a reference to real world practice (Kuji-kiri) of using hand gestures found today in Shugendō and Shingon Mikkyō. It is also present in some old and traditional schools of Japanese martial arts including but not exclusive to schools that have ties with ninjutsu