Velkeres were part of the folklore of the villages of eastern Pelion mountain until roughly the start of 20th century. Wintry spirits, they were alien personifications of snow and weather, shepherds of clouds that provided the people’s ancestors with sustenance in the deepest winter; all that until the coming of Christianity which forbade the consumption of such heavenly flesh.
Here is my expansion upon the fragmented original material. Velkeres could be used as a whole race of weather spirits (even players could be Velkeres, especially those that have been forced into human skin), or as a lone demented and utterly hostile creature, the last of its kin. They could also be tied to an ongoing war with a celestial cult or religion, or their draconic ancestry could be emphasized (the awakening of the dragon sleeping under the earth (an enormous creature of whom the mountain itself is just a part) is a distant (or not so) menace).