To save Isolde?, Xanth fed her own blood to the girl's corpse. It was this act which somehow created the virus that runs through the veins of all Vampires even today.
The Bloodlust Virus destroys red blood cells and starves the oxygen out of the bloodstream so that the body suffocates. A simple transfusion every few days is enough to treat the condition by filling the void with healthy red blood cells from a donor. However, when Vampires were first created such medical practises were not widely available and, purely by accident (as a result of the mindless feeding frenzy brought on by the Bloodlust, which many suspect is the virus's self-defence mechanism), the Vampires discovered that feeding on living beings -- human or otherwise -- could stave off the debilitating effects.
Vampire bodies naturally hunger for the blood they can't produce for themselves, driving the Vampire race to feed as monsters and, certainly in the early days, they were deserving of the label of "Scourge". There have also been rogues among them who have been lured by the bloodlust and who enjoy the kill, even though there are now measures in many towns across Elysia? that ensure a Vampire has no need to feed from a living being. These measures are far from infallible, and are in place at the whim of local governments, but blood is provided by participating pubs and restaurants as a whole subgenre of meals and beverages.
Ironically, the very virus that makes them so dependent on the blood of others also gives Vampires a power boost. They gain abilities from the drinking of blood, perhaps that are directly inherited from Xanth herself, which turn them into very effective predators.
Frighteningly, however, infection is 100% fatal for the Dracovari and dragons, while a mere 5% of Therians can survive it -- only to become the monstrous Hind. And, while Anyeli and Zanaryans can become Vampires, they lose the ability to fly? as their wings shrivel and die, meaning that only Nymphs and humans can survive the virus physically intact. Even then, the virus overwrites their genetic code which makes it impossible for them to use the powers they had previously.
A Recipe for Conversion
How to make a Vampire in one easy lesson:
- Find a victim.
- It's normally recommended that you feed from them (well, why waste a good meal?) but don't drain them too much as the virus needs a base to start from.
- Make them drink a Vampire's blood (your own is the most convenient but it can be another donor if you're squeamish). It doesn't need to be an awful lot (injection works just as well but, honestly, where's the fun in that?).
- The virus will rapidly destroy their own red blood cells so if you want your victim to survive the initial stages, keep some (non-vampire) blood to hand. (Live donors are not recommended at this point unless you lack a conscience.)
- You'll know when to feed it to them by the colour of their skin (white is best; blue means you've left it too late and you need to call a death scribe).
- Once the conversion takes hold, the new vampire will need to feed regularly. You can teach them to feed on a live (willing or not) donor, or you can buy them lunch at participating restaurants across Elysia?; it's entirely up to you.
Notes:
- The whole process takes about a day, depending on the subject's general health and willingness.
- Be prepared for a few scraps and injuries as even willing victims can become crazed during conversion.