The Sour Sea is a foul bay of polluted water which is connected with the Bitter Sea by the Straits of Nagash and surrounded on all sides by the Worlds Edge Mountains near Misty Mountain. Ages ago a great chunk of warpstone racked Cripple Peak on the Sour Sea's shore. Since then, years of water and wind erosion caused warpstone dust to seep into the waters, poisoning it and mutating the fish and serpents that it did not kill. It is said that upon drinking the water, Nagash decided to stay at its coast. Incadescent vision had blazed through his brain and dark power had surged through his veins.