User blog comment:Jopjopjop/Volume 20 Spoilers/@comment-178.128.252.204-20150826194658/@comment-26108673-20150827131331

For the first two question, I have no idea, but when the time gets closer, we will see rumours, that's for sure, just like what happened with season 3. Now, about Rias being okay with Issei having sex with the other girls, that's wrong. She is okay with him getting along more with them, but she knows that he won't betray her and the other girls also respect Rias position as being the legal-wife, but you shouldn't have any doubt that they will stop their advances just because of that. The harem will most likely stay as it is, with probably a few more girls, I guess. Rias doesn't need to rule Issei's harem, she trusts him enough, because he is the man that she chose. And yes, he is called a small True Dragon because of receiving the Great Red's flesh. As stated in Volume 12, his base status such as physical strengh and such were improved a little bit, but not that much, considering he was a normal human. No, Ophis won't be engaged to Issei because they're just friends, she is considered as a mascot by the others. She is clueless and only repeats the same things the other girls does. In my opinion, I would say no, Issei is still not equal to Vali when you compare their races. Vali is the descendant of Lucifer, but Issei is still a dragon and a human. But when you refer to strength, Issei surpassed Vali already with his new form, Diabolos Dragon. About the last question, I don't know the true reason.

If I made any mistake in any answer, someone, please correct me. Thanks.