Great Power (Rewrite Up)

Katsuo Doesn't remember much of his life, aside from the pain. Now that he's dead, though, he's free of that pain for the first time in years. Having died young, and under terrible conditions, a goddess decides to take pity on the child, and gives him the opportunity to be reborn in another world under the condition that he'd help defeat a great evil when it made itself apparent. Katsuo, of course, accepts, and it granted a system that matches the world he will be going to; one of heroes, villains, and superpowers.