Nana Shimura

Nana was the seventh user of the One For All Quirk, All Might's mentor, and a close friend of Gran Torino.

She was killed by All For One, leaving behind a son she had given to a foster family after the death of her husband. This son presumably fathered Tomura Shigaraki (birth name Tenko Shimura), her grandson.
(Source: Boku no Hero Academia Wiki)