Katsuki Bakugō wields the "Explosion" Quirk, generating blasts by igniting nitroglycerin-like sweat from his palms. This grants diverse applications like propulsion, shockwaves, and light flashes, though overuse strains his arms. Raised in an environment praising his powerful Quirk, he developed a superiority complex and aggressive demeanor. He frequently bullied his Quirkless childhood friend Izuku Midoriya, assigning the derogatory nickname "Deku" to emphasize perceived inadequacy. His arrogance stemmed from believing innate talent alone defined heroic potential. Academically gifted, he mastered reading by age four and maintained high grades at U.A. High School, reflecting disciplined study habits despite his brash exterior. Physically, he has spiky ash-blond hair, sharp red eyes, and a muscular build. His standard hero costume includes grenade-shaped gauntlets, a black tank top with an orange "X," and combat boots. Internship variations occurred: Best Jeanist modified it to appear less intimidating, adding denim jeans and removing his mask. Later, winter and stealth suits maximized sweat production for colder environments. After sustaining severe injuries in the Final War, including a scarred right cheek and damaged arm, his costume incorporated a full sleeve to conceal scarring. His adult costume retained its core design but featured streamlined bracers resembling smoke grenades. Initial hostility toward peers—labeling them "extras" and using insulting nicknames—gradually tempered through defeats and introspection. Key turning points included his kidnapping by the League of Villains, culminating in All Might’s retirement during his rescue. He internalized guilt, believing he caused his idol’s downfall. Failing the Provisional Hero License Exam due to uncooperativeness prompted self-reflection. He later deduced Izuku inherited One For All from All Might and confronted Izuku to resolve their rivalry, leading to a mutual commitment to surpass each other. During the Paranormal Liberation War, he instinctively shielded Izuku from a fatal attack, symbolizing newfound selflessness. This act awakened an enhanced explosive technique. In the "Dark Deku" arc, he publicly apologized to Izuku, confessing childhood bullying stemmed from insecurity over Izuku’s innate heroism despite being Quirkless. He acknowledged Izuku’s worthiness of One For All. In the climactic battle against Tomura Shigaraki and All For One, he sacrificed himself to save Izuku, sustaining fatal injuries. The hero Edgeshot revived him via a life-restoring technique, leaving a suture scar on his chest. Using All Might’s armored suit to stabilize his broken arm, he helped defeat All For One and prevented Kurogiri from teleporting Shigaraki away, enabling Izuku’s final victory. Post-graduation, he ranked among Japan’s top five Pro Heroes under the name "Dynamight." He funded a support suit for Izuku, ensuring his rival could continue hero work despite injuries. His appearance matured, featuring taller stature and braided hair resembling fuses. His dynamic with Izuku evolved from antagonism to respectful rivalry, marked by shared training sessions and secrecy over One For All. He formed limited friendships, notably with Eijiro Kirishima, whose resilience earned his respect. Interactions with Shoto Todoroki oscillated between competitiveness and reluctant cooperation during joint missions like the Remedial Exam.