Katsuki is a crude, arrogant, and aggressive person, especially at the beginning of the series. Katsuki tends to come off as an anti-hero, if not downright villainous for those not familiar with him. This problematic behavior goes all the way back to his early childhood days when he was known to bully a young, Quirkless Izuku Midoriya. However, after being accepted into U.A. High School and experiencing several personal defeats, one of them even coming from Izuku, Katsuki has gradually changed into a less antagonistic person, albeit still retaining a lot of his unpleasant traits.