Two years prior current storyline, at the Hiinatsuki Dormitory, Yuto performs a ritual that he says will make the other kids stronger, like him and Rokuro. However when Rokuro reaches his room, they are being turned into Impurities and ask him to kill them.
Back in the present, Rokuro questions why Yuto is still alive, while Benio can't believe that her kind brother was behind the tragedy. However Yuto tells her that his behavior was all just a lie and that he never cared for his family at all. Rokuro punches him, saying he will never forgive Yuto for everything he has done. However, because of the spell he and Benio used to save Mayura, he is too tired to fight properly.
Seigen confronts Yuto, who says he considers it normal for an exorcist to seek power to defeat Impurities, no matter the means. He also says he used Mayura to attack Rokuro only because his behavior bothers him. Seigen fights Yuto using his full power, but loses his right arm to him. Rokuro and Benio decide to face him, but Seigen protects Rokuro from Yuto's attack and tells him to leave Magano with Benio and Mayura while he fights Yuto.