User blog comment:B214/Volume 22 spoilers/@comment-90.202.240.151-20161002221704/@comment-29963364-20161003032642

I admit that would be funny. But a devil having a secret lover doesn't mean that it's a human. It could actually be one of the thousands of commoner/servant devils in their service.

Bina Lessthan could be a Pure-blooded Devil, which I believe (and really hope) she is.

Also, as for her reason(s) for joining Issei, I hope it's a combo if Ravel's and Bova's.


 * Ravel: She admires Issei because he's just like the heroes she read about as a child, and she wants to be his support.


 * Bova: He admires Issei because of his power and character, and wants to stand and fight for him or by his side as his underling/soldier.