Wrath of the Righteous
The Northmounds are a section of Plateau just north of the city of Iz in Sarkor, and was known for its heavy concentration of tombs and catacombs dug into The Plateau. Many of these catacombs had domes that reached out of The Plateau, creating mounds on its otherwise flat surface. Scholars identified these regions as bearing a weakness in the fabric that separates the Material Plane from the Abyss, long before the formation of Sarkor as a nation.
Before the appearance of the Worldwound, the cult of the demon lord Deskari, lord of the Locust Host, was strong in both the Northmounds and the city of Iz. Following the death of Aroden in 4606AR, Deskari was able to split open this fabric between the planes, creating the Worldwound.