All Might is a pivotal character in 'My Hero Academia', first introduced as Japan's number one hero. His real name is Toshinori Yagi; he was born with a quirkless background until he inherited the legendary power 'One For All' from his mentor. This ability allows him to gather power over time and pass it on. He has battled countless villains, establishing himself as a symbol of hope and peace within society. However, due to injuries sustained in fights against formidable foes like All For One, he has had to shift from his heroic form that represents immense power to a frail appearance that often challenges his image as the strongest hero. All Might serves as a mentor to young heroes in training, particularly Izuku Midoriya, whom he chooses as his successor. His journey reflects themes of perseverance, sacrifice, and the burden of heroism, marking significant moments in anime and manga history.