User blog comment:B214/Volume 23 discussion blog/@comment-31137559-20170410191626/@comment-10330822-20170412071124

Exactly, B214. But Roygun's situation is also unique, as an Extra Demon she has already been shunned by her clan for involving herself in the Rating Games, and her behavior as a cheater has likewise caused her to be abandoned by nearly everything else. So she hardly has any political leverage by joining Issei in her situation. Plus, one could argue Ravel is improving her own position by serving Issei, since she isn't in a position to inherit her clan anyway.

In short, even though she is a High-Class Devil and has a peerage, Roygun literally has nothing else. She can't do any worse than she already is. Her joining Issei's peerage would be a step up for her, not a step back. Because being involved with Issei would allow her to be a part of the Rating Games again, which is what she actually cares about.

Also, the main goal of the devils, including the reincarnated ones, is to become High-Class and start their own peerages. This is how they move up in the hierarchy, and, more importantly, how they help the devil population recover. That was the whole point of the Evil Pieces in the first place, to create a safe way to recover their numbers while promoting training and healthy competition among the Underworld.

Roygun is obssessed with the Rating Games, that much is obvious. However, her actions have made it impossible for her to act like the King she wants to be. In short, if she can't compete in the Rating Games, whats even the point for her to be a King? She might as well be a piece, then at least she'd get to compete again.

This is where Issei factors in, we have someone who #1, fits her "type" of guy she likes. #2 he's highly respected and thanks to Ruval she managed to network with him. #3 Issei could benefit from her insider knowledge of the Rating Games.

So really, both have a lot to gain by her joining. Not only would it say a lot about Issei's character to take in a shunned cheater when others wouldn't, but it also gives him a priceless edge among the other rookies in the Rating Games. Not to mention it factors perfectly into his harem overall.

Otherwise Pawn, I feel you are more debating this because of your personal feelings, which is fine, but please bring some real practicality to this conversation. King are not truely independent, they get called back to the peerage whenever needed. For example, even though Issei is "independent", he is still called to serve as a Pawn whenever Rias needs him, even if he ends up outranking her.

Roygun putting herself under Issei "helps her", its doesn't "hurt her". She is about as low as you can go already when it comes to being a King, so she might as well climb the ladder under Issei and regain her honour and perhaps her ability to compete as a King.