Episode 13

"Return of the Hero" is the thirteenth episode of the One-Punch Man anime series and the first episode of season two.

Summary
Saitama and Genos are returning from the grocery store when they see King, S Class Hero Rank 7. A reptilian monster runs away from King due to hearing King's Engine. A robot named G4 soon challenges King to a fight, and lets King go at "full power" by going to the bathroom. However, G4 will start murdering innocent civilians nearby if King doesn’t return in ten minutes. King panics because he isn't the "strongest human alive", but a normal ordinary Otaku who happened to be at the place where monsters were destroyed and was given the credit, which he started accepting to become popular. When King sees Genos fighting G4, King runs away to his house to play his video game. Saitama follows him, and plays video games with King, much to King's chagrin. Giant Crow attacks King's place, and in a state of panic King wets his pants and exposes his deception. Saitama kills the bird monster, which makes King realize it was Saitama who had saved him from the monster that gave him the scar on his left eye long ago. Afterwards, Saitama plays video games with King while Genos gets upgrades from G4's equipment after defeating the robot. Sitch announces that he will be recruiting criminals due to the increased need of help after the Dark Matter Thieves’s attack. Speed-o'-Sound Sonic leaves the meeting after discovering Saitama was not present, as he only attended the meeting to fight him. In the post credit scene, a man named Garou proclaims that this will be a slaughter party after reading the paper.