Excerpted from Tomnein’s reference books.
Minauros, the third layer of the Nine Hells, is a fetid swamp of mire and pollution. Acidic rain, bitter winds, and flesh-slicing hail rule the bog. The waters of the marsh are so cold in some places that they have iced over. In others, the dank water boils and steams with infernal heat.
Terrible creatures with no names swim the murky waters, and even devils fear to stray too far from their various cities. Where the layer is lowest, a constant dribble of slimy water sluices in a long fall to the fourth layer.
Notable cities include the metropolis Minauros, from which the layer takes its name, and the city of Jangling Hiter. An archdevil named Mammon the Viscount rules this layer. He resembles a 30-foot long serpent with a human torso, head, and arms.