Wrythian cataclysm
From Delgar
The Wrythian cataclysm was an event in which the banished city of Narthrall was magically forced back out of the void and into the mortal realm by Dark Elven void-weavers, causing the destruction of Annu Tirnin and all of the Elvari Union, as well as profoundly reshaping the geography of Wryth, transforming it from a lush forested island to volcanic badlands blanketed in ash.
