User blog comment:B214/High School DxD EX/@comment-73.223.135.87-20150818074407/@comment-3965848-20150818135417

No, from what was said in the story Jop translated it sounded like it is part of the main story, it even mentions Chichigami which was left out of BorN.

Although this story does take place after Vol.7 but not sure at which point afterwards.