So, I'll preface this one by admitting up front that I have no real support for this theory, but it tickles me.

Erin showed High King Perric the Seamwalker army. Because of this, he's going to bail out Khelt when the [Prophet] arc gets nasty.

Now, granted, Perric is an idiot, with a terrible diplomatic sense, and no real idea of what's actually going on, but hear me out. After seeing the might of Khelt when Fetohep decided he needed to use Medain's harbor, Perric was building statues and throwing parades and doing everything he could to placate Fetohep, because he was clearly terrified of the idea that Khelt could just come back and finish the job.

Now he's learned the existence of Seamwalkers, and knows that Khelt was instrumental in holding them off. Since everybody would know if that army was marching on the living world, the only place Erin could have seen it was when she was dead. So Perric should be able to put together the public information to realize that Fetohep was not only able to conquer Medain because it was the fastest route to a harbor, but that he was able to do so as an afterthought while surely devoting the most of his processes to holding back an incomprehensible army.

And Erin Solstice believes that army is going to return.

So, when Perric learns that the [Prophet] and his followers are besieging Khelt, and Fetohep didn't immediately delete them from existence, and even appear to be winning from our limited mortal viewpoints? Well, Fetohep must be concentrating the might of Khelt elsewhere. And what threat could possibly demand such attention?

The returned army of Seamwalkers. That which would devour reality itself.

And since Khelt is obviously occupied with keeping existence existing, Perric will take care of his light work on the mortal side of things. And leads an army of adventurers to knife the [Prophet] and his followers in the back.