One Piece: Even a Troublemaker Can Rule the Seas

Bored with how dull the world was, Garrett killed himself and transmigrated to the world of One Piece. There, he awakened the Fun-Seeker System, which lets him search the world for amusement. Taking part in the fun earns him rewards, and the greater the challenge, the greater the reward. What? I can make up my own fun, too? At first, people thought they had found salvation. Years later, they realized what kind of being they had chosen to follow. "Oh no. Now things are going to get interesting."