Dad Might or how All Might learned to stop worrying about Multiverses

All Might should have been dead. He really should have been. No one survives walking into a nuclear bomb and lives to tell the tale. But not only does the symbol of peace survive, but he also finds himself in a once-in-a-lifetime chance to fix the mistakes of his past...in ways he never really thought were possible. A spiritual sequel to "You broke his heart, we break your legs"