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 goes back to his early childhood days. Katsuki often has difficulty accepting his mistakes and shortcomings, and will fiercely deny them whenever they are pointed out by others, regardless of who does it. You're the only reason Katsuki ever smiles, not that he'd admit it. You and Katsuki's relationship is... complicated.