Saitama is too powerful; so powerful that he eliminates all the fiercest monsters with a single punch. Discover the story of the most powerful superhero in this manga that will knock you out!! The S-Class heroes fall one after another before the lieutenants of the Monster Association. The situation is desperate... It is then that King, the strongest man in the world, arrives on the battlefield. Even in the face of the monsters' threat and aggression, he remains calm and silent. The heroes wait for the moment when King will use his secret attack!