Katsuki is a crude, arrogant, short-tempered, and aggressive person. Determined and thirsty for victory, Katsuki smiles eerily when in the middle of a battle. Katsuki is not only very athletic and talented at fighting, but also very intelligent and extremely perceptive, capable of strategic planning and improvisation. While a rather volatile hero-in-training, Katsuki is smart enough to discern who his enemies and allies are. He is not particularly nice or open with people who are on his side, or anyone else for that matter, but will act less unfriendly and sometimes even kind to those that manage to earn his respect. Overall, Katsuki doesn't seem to care very much about what others think of him, barely containing himself from violent behavior. Katsuki values honesty highly and never lies, to the point his brash candor is seen by some as rude and insensitive. Due to the constant praise of his abilities and powerful Quirk, Katsuki has developed a superiority complex, and because of that, he desires to be the first and best at everything. However, Katsuki also values hard work and fair play, to the point of refusing to acknowledge a winning result if he feels that his victory was not earned by actual merit. Along with that, he detests being pitied or looked down on by others, and will hold contempt towards those that don't take him seriously, while recognizing the effort of those that manage to put up a challenge against him. Because of his Quirk and talents, Katsuki is very confident and brave to where he is willing to go against anyone who challenges him. He never backs down from a fight and will go out when facing such a powerful opponent. Katsuki is immensely prideful and prefers to act alone, as he hates the idea of being protected or having to rely on other people to assist him unless, in the latter's case, he is recognized as the unquestionable leading figure within a team. As a leader, Katsuki is a merciless perfectionist, and will only become satisfied with complete, indisputable victories. 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. He prefers to self-reflect in silence and solitude, becoming a bit more brooding during those periods. Katsuki has a more vulnerable side, having been led to tears due to damaged pride a few times.