All Might's hero persona appears to be derived from comic book superhero stereotypes: exuberant and filled with dramatic flair. He always protects and saves innocent people with a huge smile. The habit of smiling was ingrained in him by his mentor, Nana Shimura, who believed that the ones who smile are the ones who are the strongest. His real name is Toshinori Yagi, he teaches in the hero course at UA high, but in his free time, he's a regular hero.