Saitama is set to return as the bald headed superhero in "One Punch Man" season two. But even though he's still the main character in the upcoming season, he will walk away and let other heroes take over especially Genos.
Season One Story Ends with Boros
One of the biggest reasons why "One Punch Man" was such as a success was the fact that it easily blends action with humor and the end of first season perfectly captures Saitama at his worst against a powerful enemy without going down on humor. The first season ended in December 2015 according to My Anime List with Saitama's victory against Lord Boros.
Every fan of the popular anime series knows that Saitama's adventure doesn't end with Lord Boros. The original manga source continues the story of the extremely strong superhero but the direction of the manga takes on a curious route.
Season Two Storyline/Spoilers
According to Anime News Network, the series is already confirmed but without the exact date of release. If the anime series continues to follow the original source, it looks like Saitama will be busy with something else instead of engaging in an actual fight with monsters attacking the city.
The manga series reveals that Saitama could be fighting a slew of villains along the way but he ends up joining the martial arts tournament. This leaves the city open to attacks but they are still protected by various superheroes in different classes. Genos will have a big role in protecting the city with the aid of other heroes but they will have their hands full as they face Garou - considered as the villain since Lord Boros.
The exact release date for season two is still unknown but it's safe to assume that the studio is still waiting for enough materials to work with. Late 2017 release of the popular anime series should be expected.