So, the PCs spend five modules building up their armies, preparing to take on the hordes of the Abyss aaaaand...
A bunch of NPCs from some novels solve a major plot point for them. They leave their armies behind to go to the center of the Worldwound and find what STRANGE MYSTERIES await them there. What crazy amazing secret lies at the center of the Worldwound, you might ask?
A demonic brothel. After five epic modules, the PCs go hang out in a demonic brothel for some weird reason.
I have no idea who decided this was a good idea, but this module was really Paizo showing its embarrassing side in every possible way. I have run this AP twice, and I always have to throw out this module entirely. I wish I hadn't even bought it, because it just takes up space on my shelf. God forbid you have female players in your game, because in addition to being a totally out of left field module, it is EXTREMELY LIKELY to make them EXTREMELY UNCOMFORTABLE as your male players giggle about which demon they want to bang.
Look up the Storm King's stats online and write your own ending. You cannot possibly do a worse job on your own, even if you tried.