Kaigaku

獪岳

Kaigaku was a demon slayer in the Demon Slaying Corps, and Zenitsu Agatsuma's senior disciple under Jigoro Kuwajima. [Spoiler] He became a demon to save his own life and became Upper Moon Six of the Twelve Demon Moons, replacing Daki and Gyuutarou. He was killed by Zenitsu as retribution. [/Spoiler]