Su Ergou, a sickly boy who was born frail, traveled to the world of One Piece and became an ordinary 15-year-old boy on his deathbed, and received an unorthodox system of calling him daddy. As long as a pirate or navy who is older than him calls him dad, he can gain 1% of the opponent's strength, but only for the first time. Su Ergou and Luffy jointly formed a pirate group and became double captains. They gradually became stronger through the system, competed with other pirate groups, and eventually became the Pirate King with Luffy.
