The Burning Crusade site has been updated with further information on the flying mounts that may be found in the Outlands. Lore-wise these creatures are the offspring of the black dragon Deathwing, who traveled through the Dark Portal to Draenor, believing it to be a safe haven for some of his eggs. When Ner'zhul opened multiple portals on Draenor with the intent of invading foreign lands, the magical energies released tore the planet apart - and altered the eggs, causing the resulting creatures to have the ability to shift between the physical and astral planes. In use, a Nether Drake will have the speed of an epic mount and be able to run on the ground as well as fly through the air. How they may be obtained or what they might cost, however, remains a mystery!