The esper Tatsumaki, the cyborg Genos, the ninja Speed-o'Sound Sonic and of course the mischievous hero Saitama, a.k.a Cape Baldy. These are just some of the characters that made the debut season of One-Punch Man a certified blockbuster hit.
And for the second season, expect it to be even funnier and crazier with the introduction of new characters that provide different dynamics to the story, yet offer the same comic relief you all dig in on Season 1.
Garou - We start off with the primary antagonist in this season, the Hero-hunter Garou. The best disciple Bang ever produced in his dojo (Water Stream Rock Smashing Fist), Garou is the exact anti-thesis to Saitama's character. While Saitama embraces his super-hero persona as a hobby, Garou believes beating up heroes as a Human Monster is his destiny.
Although he already made a cameo appearance on episode 10 of Season 1, Garou will have a huge impact in the upcoming season as the primary villain of the Human Monster saga.
Fubuki - The younger sister of Tatsumaki, Fubuki is also an esper and the no.1 rank hero in Class B. Arguably the hottest female character in the series, Fubuki (a.k.a Blizzard of Hell) is very much insecure with Tatsumaki because of his sister's much powerful psychic power.
To cover up this massive inferiority complex, she uses her position as the leader of the Blizzard group to solidify her place as the undisputed no.1 in class B. Regarding her relationship with Saitama, it's unknown where there relationship will end up, but right now our hero clarified that they are neither lovers nor friends, just plainly acquaintances.
Like Garou, Fubuki also had a cameo appearance in Season 1 and she'll have a larger involvement in Season 2.
Bomb - Other than he is Bang's older brother and the master of the Whirlwind Iron Cutting Fist technique, there's not much information about Bomb. However, it is presumed that he's a high-level fighter capable of containing Garou, the Human Monster. He first appeared in Chapter 45 as he accompanies his brother in pursuit of Garou.