I am soon going to be running Ruins of Azlant and I, and my players, want to explore far more than is presented. I am condensing the adventure path down to 9 or 10 levels and then they will get to do some exploring into the actual Shattered Continent. But I need to keep things interesting and still have a kind of villain.
I thought about Demons and critters from the underdark but it did not call to me for the BBEG. I'm still considering using them but not for myfinal villian.
I want something a little stranger. I am wanting them to have to have to battle the actual land though I am a little uncertain how to go about that since there are not a lot of examples. I have plans for some plane hopping. Quiet a few rifts that have opened and have wrapped the surrounding areas.
One thought I had was using the impact locations from Earthfall be the big thing they have to take care of. Things there are really weird.
Another was them having to figure out how to close the rifts but that seems like it could get monotonous really fast.