Saitama's origin story and the hero hunter story arc is set to be the core of "One Punch Man" season 2.

According to HNGN, rumors say that "One Punch Man" season 2 is set to explore Saitama's past. As per the publication, the said story arc was not thoroughly explored in the manga; thus, it indicates that the second season of the hit manga series is set to mildly deviate from its source material.

The publication added that very little is known about Saitama's past and the only notable arc that has been covered was the part when he opted to become a hero and protected a child against a monster, using his bare hands. Another story arc common to both the comic book and the series adaptation include non-bald Saitama's training in different places.

The season 2 of "One Punch Man" is also set to feature the Hero Hunter arc, where the Hero Association wakes up under the threat of an unknown evil force. This force is revealed to be Garou, who pledged to himself that he would defeat the strongest heroes. The story arc of the upcoming series is also set to feature the Monster Association, which is known as the Hero Association's dimmer version.

According to Christian Daily, Garou is Bang's previous follower and he seeks to destroy the Hero Association, together with the Monster Association. As per the publication, the latter group is thrived by the Mysterious Beings spearheaded by Psykos.

"One Punch Man" has risen into popularity after the release of its first season, reportedly due to its faithfulness to its comic book version. Thus, it is assumed that the second season of the manga series is set to be loyal to the source material to maintain the high ratings of the show; otherwise, it is expected that the show's ratings will decline if the series deviates from its comic book iteration, mainly due to fans' disappointment.

As per Ecumenical News, "One Punch Man" manga creator Muruta Yusuke has revealed that production for the show's season has begun, but the exact release date is yet to be revealed; however, it is assumed that the anticipated season 2 is set to air in November or December this year.