Don't End!! - S2.E12

Kazuki explains that all the times she seduced Ikkou was because of her empathy of Ikkou being sent to a temple at an early age. She over-awakens Ikkou and is consequently disappears into his soul. The awakening causes residents of Tokyo to become frenzied zombies and an unprecedented amount of spirits to appear. The gang and Jotoku exorcise the spirits and Chitose manages to stop Ikkou in his awakened state. Kazuki is released and promises to redo her training.