Izuku is cold-hearted, calm, collective, calculative, highly intelligent, manipulative, inconsiderate, and sadistic individual who has no qualms of moral left inside of him, he doesn't feel remorse nor hesitant in causing misery and killing Katsuki is a crude, arrogant, short-tempered, and aggressive person, He showed to be extremely arrogant and condescending to those around him, often bragging of his Explosion Quirk's power, caustic and fiery, with a massive ego Katsuki calles Izuku “deku”