"...and those who seeked to circumvent death flocked to the Black Citadel at Xeloreth, trying to seal themselves upon the stones but only sealing their place in damnation." Book of the Twelve. Aegon 18:2:126
The Temple of Xeloreth was one of numerous structures lost to The Rot but whose name remained in the surviving texts. Recent expeditions believed they may have found the location of the temple, or at least a settlement near-by, but when a full size force was assembled they were attacked.
The temple itself has been depicted in a vast number of ways, ranging from a tower to a ring of pyramids, but it is always depicted as being solid black. Formally the site of many a black ritual, the site is commonly associated with attempts and binding souls to objects, either in the art of golemancy or in attempts to acquire lichdom.
The temple came under it's own jurisdiction upon it's founding, killing all those who tried to sack it. A such it was generally dislike by all Old World nations but very few did anything about it.
Aurora TruthShield believe such a place may hold clue that may aid her on her task, hence why she joined the operation to locate it. The attack on the expedition force and the subsequent delay have made her all the more determined to find out what lies within.