User blog comment:HollowIchigo58/High School DxD Season 4 Announced/@comment-2143738-20161103083415/@comment-9595671-20161103123034

Admittedly a Season 5 isn't very likely since a lot of light novel anime are lucky to get a fourth, but who knows, Ishibumi might be confident enough that the series will get a 5th season.

I have read some things mentioning DxD's popularity before so it might just have that chance, evne if not a very big one.