In my PBP game, I've had all kinds of nasty creatures come to Cyradon via the Royal Roads (though my players don't really know all that...). It isn't just the player characters, and the good guys that came through in my version of it.
I have some mysterious shadowy people (some good, some not so good) that are bringing all sorts of stuff to Cyradon. The Puppet Masters if you will, that are looking for a bit of chaos in the land of peace.
So when they run into a Vsori, he came from KingdomX in southern Anias west of the Dwarves. Hehe, thanks.