He is a major supporting antagonist of Kimetsu no Yaiba. He is a demon affiliated with the Twelve Kizuki, holding the highest position, Upper Rank One. As a demon, Kokushibou took the form of a pale-skinned, tall and muscular man with long and spiky black hair with red tips that he kept in a ponytail. His most notable feature is the three sets of eyes on his face with yellow irises and red sclera that have black straight lines diverging from each iris. His middle set of eyes features the kanji of "Upper Rank" and "One ". Kokushibo also has red markings resembling flames on the top left side of his forehead and the bottom right of his chin. His appearance was described to be extremely dignified and majestic by the Mist Hashira, Muichiro Tokito. Kokushibou wore a purple-and-black bee-hive patterned nagagi kimono and black umanori-styled hakama pants tied with a white uwa-obi. He carried a fleshy katana at his waist that had eyes in the space between the tsuka ito wrapping of the handle of his sword. The tsuba and blade were also later revealed to have eyes and veins. He's the demon form of Tsugikuni Michikatsu. He's also the ancestor of Muichiro Tokito and Yuichiro Tokito and the one responsible for turning Zenitsu Agatsuma's senior, Kaigaku, into a demon and joining the Twelve Kizuki. And he is Tsugikuni Yoriichi's older twin brother, the strongest Demon Slayer that ever existed.
