In episode 5 Saitama and Genos are finally going to become registered heroes, but first they have to pass a physical and written test in order to prove that they worthy of being a hero. Saitama easily surpasses the physical exam and anyone else that took it. Even though he aces the physical exams, he doesn't do as well on the written part where he only passed the entire portion by 1 point, but Genos gets a perfect score on both and is given an S rank. While Saitama is at a C rank which is lower despite him being overall stronger than Genos. Saitama and Genos are the only ones who made it out of all the applicants to actually be in a class where a A class presenter is going to teach the class. Sadly the class A Teacher is too confident in his skills but Genos and Saitama are clearly stronger. Then in class the teacher gets annoyed by Saitama for not paying attention and tries to teach him a lesson, only to embarrass himself. Later that day Genos wants to spar with Saitama because of his newest upgrades. Genos still doesn't believe Saitama's secret training strategy and thinks there must be some other secret that even Saitama himself might not know. Meanwhile Genos is giving it his all in the spar, Saitama is just messing around, not really caring about the fight. So he asks Saitama to give it his all, and right when he does the fight ends without Saitama even hitting him. Then Genos came to realize that Saitama is on another level that even he himself can't pass by just training.p.
Saitama is a superhero who has trained so hard that his hair has fallen out, and who can overcome any enemy with one punch. However, because he is so strong, he has become bored and frustrated that he wins all of his battles too easily.