Katsuki Bakugo grew up alongside Izuku Midoriya, developing a swift superiority complex fueled by constant praise for his potent Explosion Quirk and innate talents. From age four, he demonstrated exceptional abilities like advanced reading and physical coordination. His Quirk—generating nitroglycerin-like sweat from his palms and igniting it at will—erupted during preschool, further inflating his arrogance. He relentlessly tormented the Quirkless Izuku, branding him "Deku" and ridiculing his hero aspirations. A pivotal childhood incident saw Katsuki fall into a stream; he perceived Izuku's aid as condescension, permanently fracturing their relationship. Enrolling at U.A. High School, Katsuki maintained his aggressive demeanor, viewing classmates as rivals. He secured top combat points in the entrance exam yet earned zero rescue points, highlighting his victory-over-heroism focus. Early academic challenges, including the Battle Trial against Izuku, exposed his deficient teamwork and volatile temper. Defeats by Izuku and others forced him to acknowledge his limitations, though his fierce competitiveness endured. Despite his abrasive nature, he consistently ranked near the top academically, leveraging sharp strategic intelligence and perceptive combat analysis. His character development accelerated dramatically after the League of Villains kidnapped him. His rescue directly caused All Might's retirement, burdening him with profound guilt. This trauma contributed to his subsequent failure in the Provisional Hero License Exam. Later, he deduced Izuku inherited One For All from All Might, leading to a cathartic confrontation. All Might then entrusted both with the secrets of One For All and All For One, making Katsuki one of few confidants. He gradually embraced collaboration with peers, notably during internships with Best Jeanist and the Endeavor Agency, where he modified his intimidating look and refined combat tactics. Key relationships shaped his growth. His rivalry with Izuku evolved from hostility into mutual respect, culminating in a heartfelt "Dark Hero" arc apology where Katsuki confessed his inferiority complex and past mistakes. He formed reluctant bonds with classmates like Eijiro Kirishima and Shoto Todoroki, acknowledging their strengths during joint missions. His dynamic with All Might deepened into mentorship, profoundly shaping his grasp of heroic responsibility. Katsuki's combat abilities expanded significantly. Beyond basic explosions, he developed techniques like AP Shot (concentrated blasts), Stun Grenade (light-based disorientation), and Howitzer Impact (aerial spinning attack). His support gear featured grenade-shaped Gauntlets storing sweat for massive detonations and the Strafe Panzer—shoulder-mounted cannons utilizing nitroglycerin capsules. During the Paranormal Liberation War, he unlocked "Cluster," detonating past explosions simultaneously. In a critical sacrifice, he shielded Izuku from Tomura Shigaraki, sustaining fatal injuries. Resurrected via Edgeshot's sacrifice, Katsuki fought with severe impairments, including a paralyzed right arm temporarily supported by a component from All Might's armored suit. His perseverance during the Final War involved defeating an infantile All For One and aiding Izuku's ultimate victory over Shigaraki. After graduating U.A., he became the No. 5 Pro Hero "Dynamight" (shortened from "Great Explosion Murder God Dynamight"). He funded advanced support gear for Izuku and adopted a streamlined costume with smoke grenade-shaped bracers and fuse-like braids. Films and OVAs showcased consistent growth. *Heroes Rising* depicted him temporarily wielding One For All alongside Izuku to defeat Nine, displaying unprecedented teamwork. *World Heroes' Mission* featured him in a stealth suit during an international operation against the toxin-wielding Humarise. OVAs like *Save! Rescue Training* and *U.A. Heroes Battle* highlighted his tactical adaptability in non-canon scenarios, including rescue simulations and virtual card battles.