Terrorgheist

"I have seen them, at night, flapping their mighty wings across the moon. They call to me, tell me I will join them soon. Herr Doktor Leberknoedel says that I am crazy, but I know that its not true...They will carry me off to my new home, and we will dance round the moon together...Oh yes."

- Rudi, Great Altdorf Asylum Inmate



Terrorghest are the largest and most powerful Bat species to have ever existed, so large and terrifying that they've grow to the size of Dragons. In the hidden reaches of Sylvania, these titanic bats soar out from their caves to hunt horses, caravans and pegasi under the sickly skies. It is the ambush tactic of the creatures that give them their truly terrifying reputation. A Terrorgheist's vision is poor, so the swooping monstrosity ensures that its prey is rendered motionless by emitting a piercing shriek so loud and unexpected it can stun even a Bretonnian warhorse into paralysis. At that precise moment, the Terrorgheist will dive down, gather up rider and mount in its talons, and return to its lair to glut itself on warm blood.

It is the mortal remains of these troglodytic beasts that the Ghoul Kings of the caverns bind to their service. The binding process comes easily to these reclusive Vampires, for Strigoi Ghoul Kings and Terrorgheists have much in common. As Dark Magic swirls around the monstrous cave-creature, a bond of blood is formed between master and beast. Much like any other creature that drinks from a Ghoul King's veins, Terrorgheists have necromantic power running in their blood that can heal even the most severe of wounds.

In death, a Terrorgheist becomes a nightmare made real. Guided by its master's will, the monstrosity creaks through the clouds above the battlefield on blotch-skinned pinions, its rotten flesh and withered organs open to the night air. It is the deathly shriek of an unliving Terrorgheist that is perhaps its most fearsome aspect. As the magics of undeath are worked upon the beast, its cry is transformed from a simple but shockingly loud noise into a barrage of eldritch power. Some say the Terrorgheist's shriek is nothing less than the screams of the damned, channeled directly from the Realm of Chaos. It matters little to the Terrorgheist's prey, for so devastating is its sonic attack that it can cause a man to die of fright in an instant. By venting this noise as it dives down upon its prey, a Terrorgheist can cripple an enemy regiment moments before it slams into the reeling survivors, slaughtering the rest with disease ridden tooth and claw. Even when the Terrorgheist is slain, these creatures have a violent tendency to explode upon their deaths. Due to their ferocity, Terrorgheist are a highly favorable mount amongst many Undead factions.

Source

 * Warhammer Armies: Vampire Counts (8th Edition) -- pg. 48