Izuku Midiroya dies and was reborn as Lucina. Even reincarnated into a different person Lucina remembers her previous life. Now Grima is into the world Lucina previous came from and its up to them to stop him from bringing a apocalypse in a world of quirks.

Deku as Lucina parents
Morgan is his little brother.
Chrom and Female Robin

Inspired by That time I was reborn as a warrior princess by Belletiger BT and I Chosen to be reincarnated as a Warrior Princess by Blackrockshooterstar