All For One (in Japanese: オール・フォー・ワン, Ōru Fō Wan), also known as Sensei (in Japanese: 先生, Sensei) is the main antagonist of the manga/anime series My Hero Academia. He is the archenemy of All Might.
He is a mysterious man with a completely deformed face who was defeated by the hero All Might and is the founder of the League of Villains with his disciple, Tomura Shigaraki, as his successor. After his defeat, All For One was imprisoned, and Tomura took his place as the leader of the league.
He is voiced by Akio Ōtsuka in the Japanese version of the anime, and John Swasey in the English dubbed version.