The Ultimate Master
Though he’s been doing the hero gig for three years, Saitama realizes that the public knows nothing about him. Determined to get a little recognition, he decides to become a pro hero, but first he must pass the Hero Association tests and become a full-fledged member.
Aired 02/11/2015EP 5 - The Ultimate Master

One-Punch Man
Saitama has a rather peculiar hobby, being a superhero, but despite his heroic deeds and superhuman abilities, a shadow looms over his life. He's become much too powerful, to the point that every opponent ends up defeated with a single punch.
The lack of challenge has driven him into a state of apathy, as he watches his life pass by having lost all enthusiasm, at least until he's unwillingly thrust in the role of being a mentor to the young and revenge-driven Genos.