Toshinori Yagi, known to the world as All Might, rose from Quirkless origins to become the eighth bearer of the transmissible Quirk One For All, inherited from his mentor Nana Shimura. Trained by Gran Torino, he forged a pivotal alliance with scientist David Shield during a student exchange, developing signature techniques like the California Smash and establishing himself as a worldwide symbol of peace. A catastrophic battle with the supervillain All For One left him with severe injuries, including the loss of his stomach and partial lung function, forcing him to maintain a diminished true form and eventually rely on a wheelchair. Despite his physical limitations, he continued to serve as a hero and mentor, choosing Izuku Midoriya as his successor and transferring One For All after witnessing the youth’s courage. In the Two Heroes incident, All Might reunited with David’s daughter Melissa Shield on I-Island, where a fabricated crisis involving a Quirk Amplification Device was usurped by the villain Wolfram. With the dwindling embers of One For All, All Might joined Izuku and Melissa to thwart the assault, their combined strike proving victorious with the aid of Melissa’s support gear. Later, amid a global crisis orchestrated by the terrorist group Humarise, which sought to eradicate Quirk users through Trigger Bombs, All Might served as an advisor to the World Heroes Association. His strategic insights helped coordinate multinational raids on Humarise facilities, despite his retirement from active duty after depleting One For All’s remnants in his final battle against All For One. Throughout his career, All Might championed smiling as a symbol of strength, embracing optimism, tactical precision, and self-sacrifice. After retiring from frontline heroism, he continued mentoring young heroes like Midoriya, Bakugo, and Todoroki, and his enduring legacy inspires figures such as Star and Stripe, reinforcing his role as a guiding symbol in hero society.