All For One is the true leader and benefactor of the League of Villains, the primary antagonist of the Hideout Raid Arc and the central antagonist of the series, along with Tomura Shigaraki.

Once Japan's most powerful villain and All Might's arch-nemesis, his true motives are unclear and his true identity unknown. His current goal is to raise Tomura to become his eventual successor.

(Source: Boku no Hero Academia Wikia)