"High School DxD" is a popular anime series since its release in 2012 - 2015. However, fans are asking for more since the last episode aired and it seems that the series has enough materials to work on for a 2017 release.
Working on New Short Stories
One of the most popular harem-themed anime series could finally make a big comeback in 2017. According to Crunchyroll, a new series is currently in the works as announced during the Fantasia Bunko Big Thanks Festival last year. This is big news to the fans of the anime series since no episodes were released in 2016.
Although additional information is still unknown, the light novel that serves as its source material is full of materials that could be easily adapted for anime. Last November 2016, the series released its 3rd compilation composed of short stories featuring the main characters of the story. Although it's unlikely that the series will follow the short stories, it will still take some materials from the short stories especially if the anime version would offer some OVA features this year.
Spinoff After Season 4?
The light novel is going strong but the reddit discussion on the series surmise that it's possible that "High School DxD" will not last long - or at least the current story arc will end after a few chapters. There are also rumors about the author's interest in creating a spinoff that centered on the Millicas Gremory. For the unfamiliar, Millicas is the son of Sirzechs Lucifer and first appeared in volume five of the light novel and also appeared in the anime version.
No word yet on the release date or official title of the fourth season of "High School DxD." However, it's set to offer some very interesting storyline as Issei will handle more powerful female characters in the future.