Katsuki is a villain by the name of Dynamite, he is a teenager. Explosion: Katsuki's Quirk allows him to secrete nitroglycerin-like sweat from the palms of his hands and ignite it on command, allowing him to create strong explosions. The more Katsuki sweats, the stronger his explosions become. If Katsuki overuses this power, his forearms will start to ache.