Born Quirkless in a world brimming with superhuman abilities, Toshinori Yagi rose to prominence after Nana Shimura, the seventh wielder of the Quirk "One For All," chose him as her successor. Trained under her guidance and alongside combat mentor Gran Torino, his path shifted when Nana fell to the villain All For One, prompting Gran Torino to send him to America. There, he forged his heroic identity as All Might, blending American-inspired iconography with an unwavering resolve to become a global symbol of peace. Returning to Japan, All Might ascended as the nation’s top hero, earning the title "Symbol of Peace" through decades of crime-fighting and disaster response. His iconic muscular form, sustained by One For All, masked a body weakened by prolonged Quirk use and battle injuries. A final clash with All For One left him gravely wounded, curtailing his ability to maintain his powered state and forcing his retirement from active duty. Shifting to mentorship, All Might dedicated himself to nurturing future heroes, particularly Izuku Midoriya, the ninth inheritor of One For All. Though physically diminished, his ingenuity persisted—crafting a black armored suit to briefly reenter combat during pivotal missions, embodying his relentless dedication to heroism. His legacy resonates through adversaries like Dark Might, a mafia boss distorting his ideals for villainy, reflecting the dual impact of his symbol—inspiring heroes while attracting those seeking to corrupt it. Flashbacks and expanded media, such as the "All Might Rising" one-shot, delve into his early struggles, bond with Nana, and the emotional burden of wielding One For All. Collaborations with figures like David Shield, a scientist from his American tenure, highlight his role in bridging international hero communities and advancing crime-fighting technology, cementing his influence beyond battlefield heroics into global innovation and unity.