Ep. 15: Koyomi confronts the cat's revelation and Shinobu resolves the crisis at Oshino's abandoned location.

15

Koyomi struggles with the cat's claim that Tsubasa loved him, leading to a tense argument where the cat suggests killing Koyomi to end his stress. Although Koyomi considers this due to his debt to Tsubasa, thoughts of Hitagi make him reject death. He summons Shinobu, who appears from his shadow and bites the cat, reverting it to Tsubasa. The following day, Koyomi visits Oshino's former cram school to return Shinobu, finding the place ruined and empty. After school, Koyomi, Hitagi, Suruga, and Tsubasa search the location together. They discover Oshino has left, leading Koyomi to believe the mentor trusted him to handle the situations involving Tsubasa and Shinobu independently.