Lost fortress of Durgeddin the Black, abandoned since the last Elf War, hiding place of Mergil
After the Slaying, chosen by the Wyrmslayers as their secure treasury for the best of Varkar's trove, creamed off from what remained in Vorsand.
The majority of the Forgeworks level remains intact, sealed from all its exits by Stone Shape spells. Only teleportation or Word of Recall to the small shrine to Kord constructed to Hildraft can provide access. Powerful wards prevent any access via the Ethereal, and any teleportation except into the Thronehall.