In order to become certified heroes, Saitama and Genos need to take the hero test. Watch "One Punch Man" episode 5 with English sub now to find out what happened to them!
He may have saved the world many times but when it came to the ranking for the hero test, he's surpassed by Genos. Saitama demolished the physical exam, even rendering the punching machine useless after he's done with it. Unfortunately, his written exam left much to be desired, barely passing it by one point. As a result, he landed in the bottom C rank.
On the other hand, Genos did everything perfectly, earning himself an S rank.
They may have been ranked a whole spectrum apart from each other but they get through to orientations. The presenter, a Class A hero, highlighted all his skills, boasting about himself but sounding like a complete jerk instead. Annoyed at their unenthusiastic response to his boasting, he tried to teach Saitama a lesson. Of course that didn't go as planned.
Instead of trying to cause trouble with Saitama, he got humiliated instead. Watch "One Punch Man" episode 5 with English sub here or here. and find out how Saitama gave the pompous hero a lesson.
Now that they're real heroes, Genos tried to convince his master to spar with him. Of course, Saitama doesn't take the training seriously.
Angered that Saitama's just playing with him, Genos implores that he take the fight seriously. Once he does, however, Genos realized just how strong his mentor is.
Meanwhile, everyone seems to have some sort of designs on the cyborg. Amai Mask, in particular, seems to be interested in Genos.
According to Ganbare Anime, however, Amai Mask will have to go through Saitama since they're roommates now!
Watch "One Punch Man" episode 5 with English sub now to see how Saitama and Genos went through the test.