User blog comment:B214/Volume 22 spoilers/@comment-24593185-20160722022934/@comment-9595671-20160722071418

I can believe that, I do wonder if Gabriel actually outsizes Akeno in bust size? I get the feeling Azazel was implying that... which could explain why Issei may have not asked questions in putting her on his team.

I think we can all admit if breasts are involved, Issei's probably gonan jump in or agree to it in a flash, I swear even by the latter volumes Azazel can still use this to his advantage.

So basing Bina off of Gabriel who could outsize Akeno in the breast department? Guaranteed way to get Issei to have her aid him.