She Speaks A Scarlet Mist
Who can say when the blood of man was polluted with the foulness of undeath. From what blackened and defiled corner of the Oerth where first they arose is unknown. Every corner of the globe speaks of them, Bruja, Dachnavar, Draugir, Chang Kuei, Mara, Striga, Vampire.
In the Flanaess it is the same, in any decent land they are hunted and outlawed. Vampires are social creatures that form a family with a patriarch or matriarch ruling over them, but these paternal figures feel no love or attachment for their offspring and will use them for their pleasure and their defense willingly sacrificing all those they deem their 'children' for their defense or even simple gain. At times they will tire of their family and will slaughter them all gathering their tainted blood in great casks like wine to be aged and consumed at a later date.
Vampires always choose the strongest or most beautiful or talented humans to be their victims and future 'children'. Around this family are collected groups of ensnared servants or 'thralls' as the Fruz from the northlands call them. These are half-drained victims of the vampires who are ensorceled into fanatical loyalty to their vampiric masters.
While vampires may be found in ruins, catacombs or graveyards, they often join the society of large cities such as Greyhawk or Dyversas long as they can remain undetected. Some have taken over northern halls or holdings of the Sea-Barons or villas in the Great Kingdom.
There are rumors and traces of a vampiric brood gathering in the vast metropolis of Greyhawk and the local guard as well as a some of the ruling Oligarches are interested in rooting them out. While a small bounty is placed on the capture or heads of any proven thralls, a much greater reward can be gathered for the bodies (living or dead, but living pays better) of any of the Vampiric family. The Lord or Mistress of the clan would garner the greater reward but such a capture or even a defeat of one of these monsters is deemed unlikely.