Garou

Garou is the main villain of the Hero Hunt storyline in One Punch Man, and he hunts the very heroes that most people admire. As a boy he was bullied and pushed aside by other kids because he liked monsters in cartoons more than heroes, and that early rejection grew into a deep hatred for anyone the world calls a hero.

He once trained under Bang, a master of a fighting style built around turning an opponent's own force against them. Bang saw real talent in him, but kicked him out of the dojo after Garou hurt his fellow students in a sudden fit of violence. That break pushed Garou to study villains instead of heroes, and he came to believe that becoming the world's strongest evil person was the only way to protect the people he saw as truly weak.

Garou shows no guilt toward the people who help him, and he will strike down a hero or a villain the moment they slow him down. Yet he lets some heroes live on purpose, so they can grow stronger and give him a better fight later, which is the closest thing he has to a code. He also forms an unlikely soft spot for a boy named Tareo who looks up to heroes, showing a side of him his victims never see.

In many ways Garou mirrors Saitama: both are once-ordinary people who trained relentlessly, but where Saitama wanted to defend others, Garou wanted to tear the whole hero system down.