A small and frail boy and Yuichiro's first real friend, Yoichi is kind and gentle, but decided to join the army in order to avenge his older sister, who died trying to protect him from a vampire, later revealed to be Lacus. After he helped Yuichiro defeat a vampire who attacked their school, they both earned a position in the Moon Demon Company. He has high psychic resistance, but he is very weak physically. His Demon Weapon is Gekkoin lit a manifestation-type demon weapon which takes the form of a large bow.