Kokushibo



Muzan's most powerful subordinate holding the title of Upper Moon One, Kokushibo was originally a Demon Slayer called Michikatsu Tsugikuni (継国厳勝, Tsugikuni Michikatsu) and the older twin brother of Yoriichi. Envious of his brother's talent, he ends up tempted to join Muzan's side as a demon in order to eternally perfect himself as a swordsman without the worry of dying of sickness or old age. His fighting style is "Moon Breathing" (月の呼吸, Tsuki no kokyū), which directly derives from Yoriichi's Sun Breathing. He is killed in a combined effort of Gyōmei, Sanemi, Genya and Muichirō, with the latter two dying from their wounds soon after.