One-Punch Man

After saving a child, Saitama trains for years to be a hero, becoming so strong he can defeat any opponent with a single punch.

Saitama and Genos find out about the House of Evolution from Armored Gorilla and learn that Genus wants Saitama for his experiments.

A group of battlesuit-clad terrorists called The Paradisers appears in City F, and targets the fat-cat Zeniru, who in turn dispatches his bodyguard to defeat them.

Saitama decides to become a professional hero and takes up the test together with Genos. He barely passes while Genos achieves full marks.

Saitama has become a professional hero, but has yet to do anything heroic; Genos informs him that C-class heroes who don't fight bad guys are dropped from the registry after a week of inaction.