The Dim Wastes
Oh man these things suck. They’re essentially sand zombies — semi-alive corrupted humans.
The Children of Ahriman developed a gas that turns people into Sand Shamblers. It’s also possible to turn into one by being injured or possibly killed by them. Robert Pinan was responsible for the alchemical basis of their creation, though that was not his intention.
Elves appear to be immune to the effects of the sand shambler toxin.