Some TMNT stuff really isn't for little kids.
Ocho was the yōkai guardian of the Kira no Ken, a sword once possessed by Takeshi Tatsuo. She was transformed by Kitsune into a giant anthropomorphic mole, and quartered in the last chamber of the cave in Hokkaidō where the sword resided.
When Oroku Karai arrived to take the sword, Ocho made it clear that the only way to take the sword was to get past her. The human woman accomplished this by having Bludgeon throw her past Ocho, and seizing the sword before its guardian could stop her. Ocho was ready to die for her failure, but Karai instead offered her a new position as her servant, in exchange for Karai seeking a way to release her from her enforced mole shape.
Ocho took the offer, and accompanied Karai to the surface. She then worked alongside Bludgeon and Koya to slay Karai's various yakuza enemies. When Karai returned to the United States, Ocho accompanied her and helped her take control of the Foot Clan from Splinter.
Soon afterwards Kistune stole the Kira no Ken from Karai to resurrect her father the Dragon, compelling Ocho to follow her command. Kitsune used the ritual on her chosen vessel and returned the sword to the gods in the process, thus liberating Ocho of her curse as well. She returned to her human form and faded away, free at last.
- Ocho says she was transformed in the time period which bears her name. The Ōchō era of Japanese history spanned from April 1311 to February 1312—less than one year.