"High School DxD" is a highly anticipated anime because of its clever use of harem-theme supernatural hat revolves around main character Issei. Unfortunately, fans clamoring for another season will have to wait a little longer since season 4 has not been confirmed as of this writing.
According to Dates Release, developers and the animation studio behind "High School DxD" is yet to make an announcement for the series premiere. There's also no announcement that the studio has started working on the anime which should set the pace for the upcoming release.
But that doesn't mean the series in anime version is over. There are a lot reasons why fans of the series still expect the series will return. The series is undoubtedly popular since it has lasted for three seasons and new materials are still produced.
For the unfamiliar, "High School DxD" is based on the light novel of the same name by Ichiei Ishibumi. It is a harem-themed anime with a very interesting twist: the main character Issei has to deal with supernatural beings (angels and demons) that are constantly at odds with each other. He is part of the demon group and his role is to protect the ladies as much as he can.
Another reason why fans are very excited for the upcoming season is because of a unique storyline from the light novel. If the upcoming season continues the storyline based on its original source material, Issei (will be dealing with a different kind of harem. But these are not just regular girls: these are his children from the future.
A forum post in My Anime List provided detailed information about the children of Issei going back from the future to prevent a catastrophic event created by Loki. With the help of Issei, everything goes back to normal as they successfully correct the events for the future.
Confirmation of the upcoming season is yet to be announced. But fans are patiently waiting on the announcement and the premiere of the anime series. The possible storyline where Issei has to deal with a different batch of harem from the future is definitely a must watch for every anime fan.