User blog comment:The Ultimate Pawn/Clarifications on Issei's harem and his peerage/Peerage and Harem Predictions/@comment-199.195.224.47-20170204150402/@comment-31137559-20170204224247

Sorry for not listing any reasons, but these are mine:

1. Jeanne is a human and has had her lifespan drastically reduced and plus Hero Faction is over and Cao Cao is just doing his own thing so Jeanne would have no reason to follow him anymore.

2. Besides Issei defeating her, they have had no interaction. So she would be a new character that could be explored if she becomes Issei's servants. That's what creating a peerage is about. Finding potential members and getting to know them.

3. She's a beautiful girl. I know that sounds like a stupid reason for her joining Issei's peerage but this is Issei and he did say he wanted a peerage full of sexy girls. Again it would seem unreasonable since he said that at the beginning of the series when his head was only filled with perverted thoughts. But she is pretty strong and she is someone who would be a wild card so she can go either way.

4. Her Balance Breaker is a dragon made out of holy swords. I know this could be attributed to anything but what did her subspecies take that form? We know that subspecies take form based on the attributes, abilities, or personality of the user. So that could possibly be some foreshadowing.

Like I said, Jeanne becoming Issei's servant is just a speculation on my part. I could be wrong and my reasons for her joining his peerage might sound half-ass to some people. But she is one of the only logical person I can see joining his peerage. It's basically the fact that she hasn't appeared since Volume 12 and her lifespan was drastically reduced which gives her so much potential for me. It's not like characters can't change for the better. And there is no character that is irredeemable. Well there are some.