Knuckleduster, or Iwao Oguro, is a vigilante character from the 'Boku no Hero Academia' spin-off series, 'My Hero Academia: Vigilantes.' Once a professional hero known as O'Clock, he lost his Quirk and now operates in secret to fight crime. Knuckleduster is characterized by his strong sense of justice, combat prowess, and a no-nonsense attitude. Despite lacking a Quirk, he compensates with his street-fighting skills and experience. He serves as a mentor to the main protagonist, Koichi Haimawari, guiding him in becoming a hero outside the law.