S1·E11 Den of Evil

On the way to visit Aoki, Chūzenji tells Sekiguchi, Toriguchi, and Enokizu that he worked with Mimasaka during the war, although on a different project. Mimasaka researched replacing biological human body parts with mechanical ones to create soldiers who could not be killed. The only personal information Chūzenji ever learned about Mimasaka is that his wife's name was Kinuko. In a flashback, Kiba tells Yōko that he knows she is Kanako's mother. Yōko tells Kiba that she intends to claim Kanako's inheritance to pay for Kanako's medical care. In the present, Kiba goes to Mimasaka's hospital to confront him. Sekiguchi, Toriguchi, and Enokizu pick up Yōko and go to stop Kiba. Kiba accuses Mimasaka of dismembering girls to further his research, and demands to know what he has done with Kanako.