Age: 18
Birthday: July 15
Height: 181 cm (5'11½")
Affiliation: Yuuei
Quirk: Permeation

Mirio is a third-year student at Yuuei High and is part of The Big Three.

Before Izuku Midoriya, Mirio was one of the top candidates for All Might's successor and inheritor of One For All.
(Source: Boku no Hero Academia Wiki)

Whilst fighting against Overhaul, Mirio sacrifices his quirk in order to protect Eri by jumping in front of her, getting shot by the Quirk-Destroying Drug bullet that Shie Hassaikai's 'Eight Bullets' member Shin Nemoto shot into Eri's direction.
(Source: Boku no Hero Academia Wiki)