Juuzo Numa, the long-time vice principal of Takanoha High School, possesses extensive experience managing delinquent students like Saki Asamiya. The arrival of the Mizuchi sisters triggers a profound sense of foreboding in him, with his intuition signaling greater danger than he ever sensed from Saki, who was later imprisoned. Numa directly attributes the school's eroding discipline and growing student disrespect to Gouzou Mizuchi and his three daughters. When Saki unexpectedly returns from prison, he observes her unusually subdued behavior. Despite his enduring antipathy toward her, their shared opposition to the Mizuchi family’s influence compels them into an alliance. Numa collaborates with Saki, Jin, and Sanpei in a coordinated effort to gather evidence of the Mizuchis' criminal activities, undertaking the specific role of covertly spying on the family and their associates to uncover proof of illicit operations.