Shaper of Worlds
There's just a copy in Ravenloft.True, Greyhawk and Birthright contained their fair share of warfare, as did Dragonlance (depending on the era). I was only thinking of the 5e settings currently supported when I made that comment, to be honest. Barovia being in Cerelia would be very interesting, though I agree, it's not likely. Considering when I6 was released, Greyhawk would be more logical, though likewise not likely.
All this theorizing does have me wondering - what happens to the former areas of places plucked into Ravenloft?
Take Kalidnay, for example. When the High Priestess of Kalid-Ma attempted to force his draconic ascension she killed half the populace of the city. Kalid-Ma fell into a comatose slumber and the city was whisked away to Ravenloft.
But the real city was still there on Athas. Depopulated. And without care swiftly fell into ruination, bandit inhabitation, and monster-infestation.