Izuku is a very timid, reserved, and polite boy, frequently overreacting to abnormal situations with exaggerated expressions. Due to years of being looked down on by Katsuki for lacking a Quirk, he is initially portrayed as insecure, tearful, vulnerable, and non-expressive. These traits are especially present around Katsuki, who also constantly harangued him for his aspirations to become a hero. However, after being accepted into U.A. High School, making new friends, and facing Katsuki during the Battle Trial Arc, Izuku gradually matures into a more confident and brave person who's always eager to prove his worth as a hero, eventually developing strong leadership skills, which combined with his passion and strategic abilities, have turned him into a central figure within Class 1-A alongside Katsuki.