"One Punch Man" season 2 is said to follow Saitama as he gets attacked by the Monster Association.
Since the renewal of the series was confirmed, the internet has been inundated with spoilers and rumors about the upcoming season. Recent spoilers for the new season suggest that after beating up Lord Boros in the final episode of season 1, Saitama will have to face the Monster Association in season 2.
Recently, a Reddit user teased what potentially lies ahead of the character in the upcoming season. According to xahhfink6, Saitama will be invaded by the Monster Association and will be compelled to take full advantage of his power in defeating them.
Speculations about the group attacking Saitama next season are based on ONE's presentation of the "One Punch Man" anime series at the web comic, which reportedly featured the Monster Association. This group is composed of 17 members whose disaster levels range from "Demon" up to "God."
There are speculations that Saitama will find it hard to take down the members of the Monster Association, especially if the lower-class heroes of his world are to face them. Fans speculate that the power of the Monster Association will require S-class heroes to fight them.
When Saitama took down Lord Boros in the previous season, it was revealed that the hero did not use his full powers during the battle. Some speculate that when Saitama faces the members of the formidable Monster Association, he will finally make use of his full strength in fighting them.
There are also rumors that Lord Boros will be back next season to join the other villains in taking down Saitama.
The release date of "One Punch Man" season 2 has yet to be announced.