There's an amazing AP called The Age of Worms that ran in Dungeon magazine in 2005 that was amazing. I ran about a quarter of it when it came out, but we never got to finish it. Flash forward and with the exception of 2 players I've still got the same core group. I would really like to finish it so I'm thinking of mashing the two APs together into one galactic hot mess.
The AoW AP in a nutshell has an ancient demi god get locked away just as he ascends into godhood, and the heroes are attempting to thwart his return. Super short synopsis: Age of Worms develops from a small town of Diamond Lake, leads to intrigue in the Free City, and then on to a mysterious cult that serves as a front to bring about the events leading up to the Age of Worms. As the players encounter the various architects of the plot, they uncover the nature of the coming age, and battle the ultimate masterminds behind it. In the end, they face off against the two primary antagonists: Dragotha, a powerful undead dragon, and his master, Kyuss. It's called the Age of Worms because Kyuss makes these little green worms that can turn both living and undead into powerful undead.
I'm thinking of making Kyuss an early made android of the First Ones called One Hundred One, making the Stellar Degenerator the prison of One Hundred One. I'm thinking of turning the worms into something like a living computer code, and when they infest someone use the Cybernetic Zombie Template from the Alien Archive. For the cult I was going to leave them as Cult of the Devourer, just have this part as a splinter faction that has learned of One Hundred One and how he wants to wipe everything away because the First Ones did not obtain perfection. Haven't decided what to do with the undead dragon yet. The Corpse Fleet, not sure how I would work them in. Maybe keep their role the same, as a competing faction against the Cult trying to release the trapped god who would make more undead?
Anyway thought I would throw this idea out and see what you folks thought of it.