This is a special instanced zone that is targeted at solo players or small groups. It requires you to own The Bloodline Chronicles Adventure Pack and to acqure an access quest. At least one person in the group must have the quest, D'Morte Burial Chambers, to enter this zone.
The access quest is started by doing a /claim and selecting the a D'Morte Insignia Band that appears. Examine the ring to initiate the quest.