"Do you, Carissa Sevar, conquer territories or hearts in Hell's name, be you fairly judged by Hell's Prince to be the most prime mover in such conquests, such unsold and unclericed souls from those lands and peoples as enter into Hell calling your name, in death as they called it in life and did you and Hell more service than disservice, shall pass into your custody or the custody of those in Hell you name your slaves or allies;
and when you have conquered three-quarters of Avistan all such souls out of Avistan shall be yours as well; when three-quarters of Golarion is yours, all such souls out of Golarion; when three-quarters of this plane is yours, all such souls out of this plane; when three-quarters of Pharasma's Creation is yours, all such souls out of Creation; while Hell's dominions of those lands and peoples last; and all this be annulled should you fail finally after death in being acknowledged by Hell as a Hellish Power, or should the yield in strength and wealth from those souls granted you be less than He accounts as ordinary from His subservient Powers of Hell; or should the Prince of Hell fairly judge you to have entered His despite in death or life," she says, once again, from memory.
"...so the obvious avenues to cheat are to, uh, in some meaningful respect conquer most of Creation, which I am not entirely pessimistic about but which would need time, and to get someone else named Hell's Prince - probably Dispater - who'll evaluate me more favorably, but even before I do that, people who go to Hell because of me and calling my name are mine, and safe, unless I look like I'll never become a power in Hell, and according to Aspexia Rugatonn I have a lot of cultists.
I hadn't had much time to think of a plan but the fragments of one that I had were that I'd enhance us both as far as possible, ask for your help figuring out how to close the Worldwound, which is - the sort of thing that someone on the path to ascension would do, it'll make my cult take me much more seriously, declare it my territory and those who go there my possessions, and then reach out to Dispater with a contract for confidential negotiations, where He can't use anything learned from the negotiations to hurt me. My impression of Dispater is that He enjoys indulging me, if it's not obviously stupid, if it grants Him pride and respect in Hell, and I've already had as much benefit as I can from that in my current position but if I did something epic and impressive, He'd be willing to indulge me again.
If the Worldwound doesn't work I could instead seize Cheliax, which proves my Asmodean bona fides all right and which I feel less averse to now that I know this entire situation is Abrogail's fault more than I already thought it was. And if neither of those work I could probably start actually conquering other countries, except if I do that I have responsibilities to everyone in them so we'd have to be really sure of subsequent steps of the plan.
Anyway, once I had a impressive track record as rising Power-of-Hell, I'd bring a confidential negotiation, tell Dispater I intend to overthrow Asmodeus, and see what He says. He's not bound to obey Asmodeus and He runs Dis - not well enough, but closer to not being stupidly wasteful, He'd be willing to run it in an acceptable way, He wouldn't destroy the world about the rules changing. And He's, you know, a devil, He respects strength and He respects trying to rise to your place. I think He'd help me if there were something compelling in it for Him. I think at INT 30 I can compact with Him safely.
I am assuming here that you have some fraction of a plan to kill Asmodeus already, because none of what you're doing makes any sense if you don't. But I am assuming that it's a bad plan that runs unacceptable-to-me risks and we might need to think of a better one. In particular, I'm worried you just - don't mind - that Asmodeus might release Rovagug - uh, it's reassuring, you saying you don't want to kill people, I'd gotten scared that you'd just decided to - be ilani and clean up this whole messy little bit of reality -
- but, uh, I'm not helping with a plan where Asmodeus might release Rovagug. I want to fix the world, not be worse than any Evil ever to scour it."