This zone is visible on the world map after you start the quest There and back again. This quest can be obtained from Zemekkys in Gates of Morning.
A dungeon-style zone. Be prepared for lots of orc cryomancers and pyromancers.
There is a special locked room here called the "Room of Death", filled with multi-hued wyrms. Clearing that grants an achievement. The Blood-Runed Athame needed for the There and back again quest is found in the treasure room on the second level. The treasure room is filled with a large amount of tier 4 and tier 5 items.