User blog comment:Super ea/High School DXD/@comment-175.140.254.147-20120623144021

Now, from the next volume it will be the start of the fourth chapter! That’s how I would like to do it, but volume 13 would be a interval and be collections of short stories. I’m planning to include short stories such as Raiser’s return and about Magical Levia-tan which has popped up the main story. There will also be a new written one to be included as well. And on top of that volume 13 which is collection of short-stories will have a limited edition which will come with anime bluray! It’s a special where it will concentrate on Rias and Ise’s relation who have started to live together and could be considered as episode 13 of the anime. The truth is I have written the story for the episode of Bluray. Please look forward to it!

Quote from Volume 12 afterword at Baka-Tsuki. So maybe the OVA will link us to some hint in season 2.