Lost Capital of Asuria

The capital of the Asurian empire, Asuria, was located on the west coast of the Asurian Peninsula. It is...no longer there. In its place is a barren stone crater, where no plant will take root.   In the dying days of the Empire, Kalshazzak Aesymnetes conducted an unholy ascension ritual, in hopes of claiming his seat among the gods. The exact details of this ritual were understood only by him and possibly a handful of long-dead mortal disciples, but what is known is that he sacrificed the entire city to obtain his power. If this is so the city, or at least the lives it contained, was not merely destroyed in a cataclysmic explosion; something far worse must have happened to it. Some speculate that the city was somehow absorbed into another realm, one suffused with necrotic energy, and the inhabitants souls converted to the necessary energy to reforge Kalshazzak's soul into that of an immortal.   This belief has not stopped anyone from searching for it. From treasure hunters (or perhaps grave robbers) hoping to discover ancient treasures of the empire to archaeologists hoping to explore the ruins to scholars seeking lost knowledge that might be preserved within its halls of learning, there is no shortage of fools who devote their lives to seeking it. However, if any have been successful in locating it, none have survived long enough to make public their accomplishment  

Secrets

The city was dragged into the Plane of Shadows, and is bound to that plane by the same ritual that preserves Kalshazzak's immortality. If that ritual were to be disrupted, the city would return to its place in the mortal realm, and Kalshazzak would be rendered mortal once more. He would still be immensely powerful, but if slain, he would stay dead, rather than needing to be sealed away. However, even surviving in the city for more than a few seconds would be a challenge, given the necrotic magic that pervades every stone of it. Furthermore, not even the gods are aware of its presence, or what disrupting the ritual might do, for the Plane of Shadows is a realm of cosmic secrets.