Iwao Oguro is the vigilante known as Knuckleduster. He was formerly the Pro Hero known as High-Speed Hero: O'Clock in Japan, and Hyper Quadfist in China. He is a towering, heavily muscled man. He has short dark hair and visibly thick eyebrows, and also possesses heavy stubble and a prominent scar running diagonally down his left cheek. Knuckleduster is an individual with a strong sense of justice and drives to do the right thing. He has no government-issued hero license, but this does not stop him from putting on his costume and going out every night to fight street-level criminals and local gangs to keep his neighborhood safe from crimes most "Heroes" will not bother with. Despite this reckless streak, he does genuinely admire Heroes for the work they do. This is probably because he also used to be a Pro Hero before his powers were stolen, which left him Quirkless.