Katsuki is a young man of average height, with a slim, muscular build, and a fair skin tone. He has short, spiky, sandy blond hair with choppy bangs that hang over his eyebrows. His eyes are sharp and bright red in color. His Quirk is Explosion (爆破), which allows him to make explosions from his hands by detonating the nitroglycerin-like substance he sweats; throughout the series, he learns various different ways to apply this. Overuse of the Quirk can potentially break his forearms.