She is a high school student who became the host of the War Devil, Yoru, making her the inhabitance of the War Fiend, though she still retains her human personality when Yoru allows her control, making her a rare case of a living Fiend host. She is the War Devil who embodies the fear of war. She is a member of the Four Horsemen, who now occupies Asa Mitaka's body as a Fiend.