I have Adrestia, she has a major grudge against upper-class English society generally for turning it's back on her family, and she wants to ruin some (at the moment non-specific) well to do family. It would be great to have her blackmailing the phoenix society, while also being in. Threatening, or causing scandals to destabilise the social hierarchy - then being all shocked Pikachu face when shit goes down. She's been in England for about a year, so would be enough of a society fixture at this stage, more money than god, although not married so would have to be an eager beaver junior member.

There would be nothing to say that she had to be the only force for chaos.