Karsus's Folly

Karsus's Folly was a climactic event which caused the end of the Netherese empire.

After decades of war with the Phaerimm, the homeland of Netheril was quickly becoming a wasteland. In a desperate bid to defeat the phaerimm, Karsus tried to wrest the mantle of divinity from Mystryl using the spell Karsus's avatar. He failed to realize that Mystryl was the only being with the experience to fix the damage that the war between the Netherese and the Phaerimm was causing to the Weave. He inadvertently caused all magic to cease to function, sending the flying enclaves of Netheril (which relied on magic to stay in the air) crashing to the ground. All were destroyed except for four - Anauria, Asram, and Hlondath, which were saved by the reincarnated goddess Mystra, and Thultanthar, which was pulled into the Plane of Shadow to strengthen the twelve princes spell power.