Mujōki

Mujōki, the Ghost of Impermanence, was a competent mazoku of Emma-Ō, who appointed him as the warden of its legion at Tōshigoku Castle, in the new region known as Tōshigoku. The legion ranks swelled swiftly with souls who died engaging in pointless violence. Eventually Fu Leng deployed crafty oni to squeeze through Gaki-dō's fraying edges, infiltrate Tōshigoku Castle, and kidnapped Mujōki. An impostor ruled in his place, taking his shape and sending false reports to Emma-Ō. The false Mujōki was a sadistic oni who enjoyed violence for its own sake, training Tōshigoku's denizens in increasingly brutal martial arts and tactics.