The untold story of kokushibo's transformation into a demon in demon slayer description: Dive into the unknown reasons behind kokushibo's decision to embrace. Webkokushibo’s transformation into a demon was driven by his desire for greater strength. His younger brother, yoriichi tsugikuni, was feared even by muzan. Weblearn about kokushibo's dark past, personality, abilities, and relationships in this comprehensive article. Find out how he became a demon, why he hates his. Webkokushibo’s mark, linked to moon breathing and a demon transformation, differs from tanjiro’s unique mark, acquired through a perilous incident. Therefore, the answer to the. Webafter being decapitated by two marked hashira, kokushibo is able to regenerate his entire head and successfully conquer death from a decapitation via nichirin swords, a feat.