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. Because of his attitude and vulgar language, Katsuki's U.A. classmates often react negatively to him, although they have come to appreciate his skills and warm up to his personality.