Kidōmaru

Kidōmaru (鬼童丸) was a evil spirit in samurai attire who helps Yomi Isayama.

Plot
Kidōmaru is critically injured by Kyouko Mine, but not before he almost kills her and he was later finished off by Kagura Tsuchimiya.

Power and Abilities
Kidōmaru is a swordsman who is very powerful.

Etymology

 * The surname means "demon, ogre" (鬼) (ki), "juvenile, child" (童) (dō) and "round, circle, pills, purity" (丸) (maru).