Kyoushirou Kamui

Kyoushirou Kamui is an older, wandering samurai who took in little Kyouichi Houraiji after his father was killed. Kyoushirou became Kyouichi's kenjutsu shishou (swordsmanship master) and struggled to instill in the brash boy a sense of self and true justice; he could tell Kyouichi was running away from his feelings over his father's death, and it turned him into a self-righteous bully, much to Kyoushirou's disappointment. A mysterious man, Kyoushirou eventually disappears from Kyouichi's life during middle school, once more taking to the unknown road for no apparent reason. He leaves him in the care of the drag queens at Club Diva, where Kyouichi takes Kyoushirou's place as their "samurai-for-hire".

Although not much is known about the wizened samurai from the omake (extra) episode in the anime, Kyoushirou was a key player and comrade-in-arms to Genma Hiyuu (Tatsuma Hiyuu's biological father) with a gaiden (side-story) in the original videogames "Tokyo Majin Gakuen Kenpucho" and "Tokyo Majin Gakuen Oboro-Kitan".