User blog comment:B214/High School DxD EX/@comment-108.224.166.119-20160204202049

I just wanted to point this out Airi made mention of a "House of Hyoudou", that means either because of Issei's importance the hyoudou family either:

Theory A: Become a prominant family in the underworld. Like one of the extra demon families for example. (This is unlikely)

or

Theory B: Have become a prominant family in the general supernatural community. (Examples: The Five Pincipal Families, the House of Pendragon, etc.)