User blog comment:B214/Volume 23 discussion blog/@comment-3965848-20170320172125/@comment-30048084-20170320193534

@Striker Issei isn't the kind of person to have mistresses only wives.

technically at this moment he has 5 fiancés Rias, Akeno, Asia, Xenovia, Irina. Koneko isn't at fiancé level yet.

Mira is already in Riser's harem if I am thinking of the same person she is merely a fan of Issei. Chances are Kiyome won't make an appearance again or make it into the harem.

Bennia and Tsubasa are highly likely. I wouldn't take Gabriel out of the running just yet you never know with Issei even though she is currently the top angel. Serafall is protected by the wall of Sona, personality and rank. Yasaka is impossible.

The rest of them I would also think as possible we might even get some more from the Sona bunch heart's stolen during the match in Dx4. Tiamat in particular with the whole lost item situation.