Okaaz Storn is great hole, seven miles across, in the northeastern reaches of the Sands of Hell. It drops 2200' down into the Underdark region Miryeril. Over the ages, the shifting sands have fallen into this hole where they eventually formed an island. This island, technically in the Underdark, is surrounded by the ocean waters of part of Erethor that is also under the continent's surface.
The sides of Okaaz Storn are dotted with caves and passages, with some leading into the Underdark. Some of these areas serve as lairs of wyverns, rocs, dragons, and other far ranging creatures. During times of feeding, they either fly up Okaaz Storn to the surface to hunt or prowl the sub-surface channel Ilimys-Erethor Cut.