Luckily, a chance encounter with the world’s greatest hero, All-Might, reveals a secret in which All-Might must bestow his powers onto another individual.
Deku has the ability to be the greatest hero of all time, provided he can harness the awesome power of it without dying in training first.
This is where the hero, Deku, comes into the story.
He desperately wants to be a hero, but unfortunately, has no powers manifest as he matures.