Kalshazzak Aesymnetes

Kalshazzak Aesymnetes is a legendary being from the days of the Asurian Empire, a mage of unsurpassed power who feared nothing but his own mortality. A figure shrouded in conflicting legends and myth, few truly know the full story of this ancient being, or the ultimate truth of his fate.

History

Legends tell that he grew in power and prominence in the empire, his powerful magics being used to fuel the empire's rise to greatness. When the previous emperor passed, there was no more beloved choice for the throne than Kalshazzak. This proved to be a mistake, for Kalshazzak still feared death.
During his reign, he and his apprentices conducted heinous experiments upon the people of the Empire - at first just captives from neighbouring realms and provincials who nobody in the imperial core would miss, but soon these experiments grew to involve entire cities. He studied magics to prolong life, burning the very souls of other beings to buy him a year here, a decade there, ever hoping to find a way to go beyond, to transcend mortality entirely and to ascend to the status of godhood. Many thought to resist, his ever growing experiments soon becoming impossible to hide from his subjects, but by that point, mere mortals were no real threat to him.
His research culminated in an event now only whispered of as "the Rot of Caelester." This was a ritual of necromancy on a scale that had never before been attempted, and it nearly succeeded. Necrotic energies surged throughout the city. Wood decayed to dust, food withered on the vine. And the people were consumed from within so virulently that not even the skeleton remained. And all that energy flowed to the man at the heart of it all: Kalshazzak Aesymnetes.
Finally, the gods intervened directly. By divine law, a mortal, no matter their activities, can only be dealt with through mortal proxies. But finally, Kalshazzak had crossed this line. Through the sacrifice of thousands of lives, he finally achieved immortality...and opened himself to the wrath of the gods directly. Their punishment was swift and terrible. Whereas he caused others to wither and decay, he withered and decayed in turn. What powers he had were diminished in kind. But an immortal can never truly be slain, and he was now immortal. A weakened undead creature not unlike a lich, but still powerful by the standards of mortals and still as eternal as the gods themselves.
But the gods were not finished. Inspired by divine guidance, powerful warriors and mages from across the world of Eshor gathered, creating a host of heroes like the world has never seen before or since. They marched upon Caelester, battling hordes of undead under the thrall of Kalshazzak Aesymnetes, last emperor of Asuria. Finally, they conducted a ritual of their own, binding the immortal lich in a tomb deep beneath the ground. Several artifacts of great power were used to bind this seal together. The linchpin of this binding is a Sacred Blade, now watched over in secret by a hidden order of monks within the temple complex known as the Caelester Abbey.
This order grows fearful. They fear that the recent earthquake was no mundane disaster. A secret prophecy in the Abbey's archives whispers of a great sundering of the earth that foreshadows the return of Kalshazzak.