Ghorion was once one of the Three Troll Kings of the Cloudsteeth Mountains. Undeath has only made him crueler, and much, much more powerful.
They hop, they bleat. They shed their skins.
High above the lands of the living, where frost and howling of the wind reign, the morbid monument to a faith long dead calls the deceased on a last pilgrimage.
"Such a delirious monstrosity would never be allowed by the Unconquered Sun! It is the spawn of the hell-fiends sent to do their foul work! It and those that brought it into being must be destroyed!" - Lux Sialos, Knight of the Shining Crusade
The Eternals are one of the few races who survived the awakening of the Gods and the fall of Prime Creation. They were solitary, but powerful, weavers of essence and were locked in a bloody war with the Other Ones, another race which survived the Gods.
If you want to add a "supernatural" touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.