Whispers of one thousand dead one thousand times over echoed throughout the chamber so cold it felt as if all the life had been sucked out of it and doomed to reside in the dark pool from which the sound resonated. There is more truth to that speculation than one would like to believe. The pool was so dark that it made the ancient stone walls look like clouds that were captured from the highest reaches of the stratosphere, brought below the ground and made solid; so cold that if the substance contained in that pool had truly been water, it would have become ice so frigid that it would be beyond all hope of melting; so deep that it had been rumored to extend to the reaches of the underworld itself. However, no one dared venture to prove this, for the arcane and supernatural mystery of this liquid filled chasm was sufficient to deter even the bravest and most knowledgeable of mages and explorers from testing their hypotheses.
Created in the very beginning of time by Mortrius, the god of death, the chamber was said to house the orc armies of Atem-Mentirius, the god of life. After creating the Earth and putting so much of his power and energy into perfecting the evolution of the planet's earliest and most primitive organisms, Atem-Mentirius began to harbor a growing resentment against Mortrius that increased exponentially with each of his creatures that withered and died before his very eyes. His salty tears watered the land and became the oceans and seas from which even stronger and more resilient forms of life emerged. Nevertheless, there always came a time when Mortrius would extend his ephemeral plasma claws unto Atem-Mentirius's creations and with the swiftness of a raging hurricane, but the gentility of a light breeze, take the part of himself that had been invested in it under his dark, translucent cloak and return that part back to Atem-Mentirius.
Though this allowed him to give life to another, more advanced creature, the god of life was horribly upset that he had put a part of his divine force into an object, made it grow and change and gave it animation only to have its spirit later sent back to him in the hands of that destructive demon, Mortrius. His heart bled as the heart of his animals stopped, his eyes drooped and shed tears as his plants wilted and withered away every winter.
Around the time of the dawn of the human race, Atem-Mentirius had devised a plan to unnaturally prolong the life of the population of the planet. Disguised as a wizard, he taught every spellcaster he encountered a series of charms and curses to give them immortal life. This information spread more quickly throughout the Draconic-speaking world than any other part before the invention of the Common language, another one of Atem-Mentirius's pet projects. Its purpose was to act as a carrier for the spells of immortality, but by giving everyone a way to communicate directly with any race, it prevented most wars and petty disputes, further pleasing the god of life.
Noticing that power hungry wizards and sorcerers had learned how to cast spells they shouldn't have to prevent him from ending their lives, Mortrius cursed them with decay that would progress naturally so they would regret ever letting Atem-Mentirius's words into their ears. Upon hearing this, Atem-Mentirius turned to the orcs, the strongest and most advanced race of the time period to aid him in his battle against Mortrius.
Though Mortrius did not have the power to create new life, he did have the power to mutate existing organisms in such a way that they could destroy another species. And so he took the simplest one-celled amoeba he could find and manipulated its genetic structure so that it fed off of the life force of orcs.
It started out as an innocent cold that spread unusually fast throughout the tribes of orcs aligned with Atem-Mentirius. Soon the orc armies dropped like flies as the succumbed to an illness far worse than the Black Plague. After death, Mortrius took the spirits of the orcs to the dark pool to linger helplessly until he saw it fit to either use them in an army of his own or set them free to rejoin the Life Cycle. Those remaining alive aligned themselves with him in exchange for their lives. He spared them, but showed no mercy with Atem-Mentirius. He was doomed to stay in the pool to be tormented by the very souls he had condemned to be there, hiding in plain sight where no one with the power to release him would think to look; underneath the castle that he had built and inhabited since the beginning of time to wait for the day that would never come; the day when he would be found. And set free.