Once Japan's most powerful villain, and All Might's arch-nemesis, his full identity is unknown. His ultimate goal is to steal his younger brother's Quirk, One For All, the only Quirk that can oppose him. He is the mentor of Tomura Shigaraki, having spent the young villain's life shaping him into a successor, and a vessel for his power in a plan to eventually conquer the world as a self-proclaimed "demon lord".