Omihiko Yamada

Yamada is a mysterious classmate who is close to Hoshino

Yamada is actually the reincarnation of a famous author from the Taisho period, Kuroiwa Onitaiji. He killed and assaulted 9 boys in order to write his final novel Total Eclipse of the Eternal Heart (Gesshoku Kitan) and was cursed with immortality until he is killed by all of the reincarnations of his victims.