Katsuki is a crude, arrogant, short-tempered, and aggressive person, especially at the beginning of the series. Katsuki tends to come off as unheroic; this problematic behavior going all the way back to his early childhood days when he was known to bully a young, Quirkless, Izuku Midoriya. He showed to be extremely arrogant and condescending to those around him, often bragging of his Explosion Quirk's power, and even boasting that he would take on his entire middle school class.