User blog comment:B214/Volume 22 spoilers/@comment-14.201.211.143-20160910010909/@comment-10330822-20160910112413

Yeah, unless they make some kind of trade arragement with Brave Saints and Evil Pieces, Irina can't go to Issei. I also don't know if Kunou will be because she is the heir of the Yokai in Japan, it probably wouldn't be proper to make her a Pawn. She might just be a future child to one of his children. He has so many they can't all be from his peerage.

Elmenhilde is a tricky one, it would make sense since she isn't a leader of anything, just a representative, and we know she has a child with Issei later. I'm more curious as to why she's taken a liking to Issei in the first place, especially since she is a blood purest. Going after a Dragon/Devil, reincarnated or otherwise, seems against her code. Honestly, I don't think there should be a problem in general, because Devils are typically considered to be superior to Vampires, especially a Devil of Issei's caliber. Even if he isn't a Vampire, their child should be far stronger than any pureblood.