In the time before the old ones, the planet was dominated by great beasts. While the dragons of today pale in comparison to the dragons of old, the dragons of old are similarly mere shadows of the monstrosoties that walked the world before the coming of the Old Ones.
Nearly all of them are dead or lost to time, but a slim few know the name of a single True Great Wyrm who slumbers beneath the waves. They call it Tyran: The Great Devourer
Though his name has been stricken from the Plaques of history, Disgraced Slaan Priest Ick once questioned the wisdom of reshaping a world that rightly belonged to such majestic creatures, and for this, he was struck down; forced to walk the earth with his own feet.
For centuries, he brooded and contemplated his misery, until in the great contemplative divinations, he saw Tyran in all its majesty, and with a proactivity uncharacteristic of his race, he made haste to find its place of slumber.
Ick does not share with anyone what happened when he encountered the sleeping beast, but what is known is that he brought back a vial of some fluid only obtainable from the Wyrm itself, and proceeded to create his own spawning pool, using the essence of Tyran rather than the works of the Old Ones.
This pool worked neither on the magics of geomancy, nor the winds of chaos, but the most primal of blood magics that predated the Old Ones interference. Each new spawning requires a great blood sacrifice. No pomp and circumstance, or pleading to fickle gods, is required, merely blood, bone, and sinew, given directly too the pool itself.
These dark spawnings have frequently been mistaken for Lizardmen throughout the centuries, but recently Ick has discovered a new and insidious deviation of his Dark Saurians from the normal breed: they can procreate with lesser species, creating dark hybrids. These hybrids can often pass for their parent race, but remain loyal to their Dark Saurian progenitor.