Although the studios have yet to announce when "One Punch Man" season 2 is coming, a report from IBTimes states that the new season will be introducing a brand-new love interest for Saitama and this may form a love triangle involing the new girl, Saitama and one of his allies. 

The report points out that the rumors suggest Saitama's love interest may be one of the characters already introduced in season 1 although the identity of the girl has yet to be confirmed. Fans speculate that this love interest might be Fubuki, leader of the Blizzard group, but Fubuki has yet to make a significant appearance in the series.

It is further stated in the report that the show will introduce a brand new villain while still spending a few episodes to close the story arc regarding Lord Boros. Garou and Amai Mask are also rumored to become main enemies in season 2.

Fans note that these storylines regarding the return of Lord Boros and the other villains are not directly pulled in from the manga which indicates season 2 might stray from the established source material. It is noted that even season 1 strayed from the original manga multiple times and is not a direct adaptation of the manga's events.

Should the series follow the plot arcs from the manga then it will focus on the King story arc and then the story regarding the Blizzard group. This is potentially where Fubuki and her lackeys will be introduced. However, in the manga, Fubuki only became a good friend of Saitama but never as a love interest. This may change in the anime.

According to the report, "One Punch Man" season 2 is likely going to premiere in 2017 although the studios have yet to make an official announcement. Neither the studios or the networks that stream the anime have hinted when season 2 would premiere.