Upper moon one he is still alive but he’s technically not human anymore he’s not a demon from hell he’s an oni a demon from Japan that can turn humans into demons if he wants to through a bite pale-complexed, tall, muscular build. He possesses long, black, spiky hair with red tips tied up in a ponytail. His most noteworthy feature are his six eyes present on his face, and his middle yellow irises consist of the mark of Upper Moon One. His appearance is described as profound and majestic. Kokushibo wears a purple-and-black hexagonal-patterned nagagi kimono and black umanori-styled hakama pants tied with a white uwa-obi he doesn’t react to much and is the strongest of the upper moons he used to be a demon slayer he still uses his breathing style moon breathing with his katana he is very fast he is five hundred years old and regenerates fast he doesn’t know if anyone still uses moon breathing since he never taught it when he was human moon breathing has sixteen forms and is hard to master but kokushibo knows how to use it since he created it he used to be a hashira the strongest rank in the demon slayer corp he hopes that someone may still be able to use moon breathing but he hasn’t found a human that uses it yet he wrote his breathing style down hoping that someone might be able to learn it but he doesn’t really get his hopes up to much he does know that if he finds someone that can learn from his book he will definitely turn them into a demon so he isn’t lonely since demons basically become immortal when they turn to demons and he can bite to break skin and turn someone into a a demon since he’s a strong ranked demon