yeah i though it was a bit weird that they set the place in a Swamp since it one of the Biome that is related to Gloomspite Gitz
at least from how i gather from the lore
GloomSpite: Caves, underground caverns, Swamps, place for Nocturnal beings
Gitmob: Plains, grass lands, and Arid regions
Grotbag: the Sky and Mountains
Theory: maybe Belakors big storm is blotting out the sun in GHur and the Sun Grot don't like this