Bloodgorger Wyverns are dreaded nocturnal sanguivores that hunt the night sky in search of blood to feast upon.
They prey on creatures of any size, although cattle and other easily subdued domestic animals are their preferred target. Using its excellent hearing and ultrasonic screeches, a wyvern can echolocate its way through forests, caves, and cities without a light source. When its prey has been located, it launches venomous tail spines to induce paralysis before exsanguinating the helpless victim. There exists record of a particularly thirsty bloodgorger wyvern that managed to drain five draft horses dry in a single night before a terrified stablehand found the beast attempting to roost in the rafters. It was too bloated to fly away, and the locals managed to slay it with few casualties.
Unholy Hybrid. The bloodgorger wyverns that haunt the pastures and stables of small towns today are all descended from an ancient experiment. Long ago, a powerful vampire decided to extend her influence over the wyverns that dwelled in the vast cavern beneath her castle. She began feeding them meat that she had laced with concoctions of her own blood. Rather than curse these wyverns with vampirism, the experiment resulted in something entirely new. These draconic creatures became more batlike, unnaturally hardy, and developed the monstrous bloodthirst that distinguishes them today. Their stinger became projectile spines, akin to a manticore’s, that can deliver a paralytic venom at range.
The experiment was ultimately a failure however, as the wyverns never submitted to their creator's will. The resulting vampire-dragon hybrid remained wild and unruly. Although tameable, doing so is a lengthy and extremely risky task that is not easily replicated from one wyvern to the next. After decades of trials, the hybridized wyverns were expelled from their creator’s lair to wreak havoc on the world, and this they do with remarkable talent.