Vampire Lord on Zombie Dragon / Terrorgheist

Dragons are a proud and noble race that ruled the skies long before the coming of Chaos. However, like all mortal creatures, they will eventually succumb to old age or injury, and they will fly across entire continents to their final resting place - the Plain of Bones. It is to this inhospitable place that a Vampire will travel to claim an Undead Zombie Dragon as his mount, raising its ruined carcass from the desert sand on a pillar of Dark Magic to do his bidding. A Zombie Dragon is borne aloft by great tattered wings, its body covered with thick, withered hide. Though once it breathed fire capable of melting steel, it now belches forth a cloud of noxious gas, foetid with decay, which strips flesh from bones and corrodes armour. In death, its teeth and claws are as sharp as they were in life, able to tear a knight and his mount clean in half before feeding upon whatever's left. 

When such a fearsome monster is used as a steed by a powerful Vampire Lord, even the greatest heroes and sturdiest warriors fight a foe against which there can be no hope of victory.