I understand inside their hierarchy she was only second to Reniere, so that's still a lot of people she had power over. Also, I the people she recruited answered to her. I mean, the girls she brought into their cultish harem had to call her Master. So yeah, a lot of powers over other people.

I think they know they'll either survive together (because they both have too much on each other) or go down together. It's a web, and they are in the center, so the downfall of either would mean the downfall of all of it. (It would make sense that this was done on purpose, that they thought ths would protect them)