Birthday: June 10
Height: 220 cm (7'2")
Affiliation: Yuuei
Quirk: One for All

All Might is the No. 1 Hero and the "Symbol of Peace." He is famous for routinely saving the day with a smile on his face.

In his hero form, All Might is a very tall and muscular man whose design resembles classic American superhero comics. His whole body has more shadows than a normal human being.

However, in his true form, he appears to be grossly underweight. During an encounter with a villain five years ago, he suffered life threatening injuries; the medical procedures that saved his life left him with an extremely frail physique. Now he can only serve as a hero for three hours a day, as his body cannot handle any more exertion.

All Might meets with All for One, the enemy who gave him his fatal wound, once more during the Hideout Raid arc. After a tough battle, All Might manages to defeat All For One, but ends up using all of his remaining power, ending his hero career once and for all.
(Source: Boku no Hero Academia wikia, edited)