"One Punch Man" definitely ranks among the best animes to come out in 2015. The anime TV series is funny, extremely unique and gives viewers the lighter side of being a superhero without ignoring the responsibility in saving the world.
According to My Anime List, the first season of the TV series ran from October to December 2015 featuring 12 fantastic episodes. Even though with limited episodes, it is extremely popular among anime fans and it's rating in IMDB has been impressive as it stands at 9.4/10 as of this writing.
Since it's in the height of its popularity, it would be foolish for the production studio not to continue the fun and amazing TV series. But before any of the fans demand for a "One Punch Man" season 2 release date, it should be noted that the manga should set the story first before it is adapted to anime.
Every anime fans know that some of the best animes is based on a manga and enough content should be published first before a single episode is produced. According to The Bit Bag, "from the looks of Yusuke's anime episodes of 'One Punch Man,' it might be getting closer to the manga episodes, this might mean that the anime episodes will be delayed, depending on how close the manga series is to the anime."
On the other hand, a report from when-will.net points to a spring release of the beloved anime believing that there are enough content to be produced at least for the same number of episodes. The report indicates that the second season could be released as early as spring this year.
Fans should have to wait a little bit before the anime gets its second season. If the manga should be followed, we'll get a good glimpse of Garou and Amai Mask in the second season which promises a very interesting storyline.
In the last episode of season 1, Amai Mask confronted the S-Class heroes and acted very suspicious which might lead to him turning to a heel. Also, *warning: spoilers ahead* the current arc in the manga features Garou battling Metal Bat and this might lead to a match between Garou and Saitama.
