The main antagonist of My Hero Academia, All For One, is considered a supervillain among fans. Yet, the primary reason why fans classify All For One as the ultimate villain is due to how his quirk, All For One, is overpowered. He can give and steal other individuals' quirk abilities and use these quirks for his selfish goals.
Source：https://www.cbr.com/mha-afo-anime-greatest-villain/
