Essentially, a vampire is a human being that has died and has been subsequently resurrected by either the bite of another vampire, or through some other supernatural means. Complex diabolic pacts and certain obscure black magic rites have been known to create vampires; evil sorcerers and some lycanthropes that have died may rise again to become vampires; extremely evil men (or women) who die while committing an evil act may return as vampires. The most common and sure-fire method of becoming a vampire is to die from a vampire bite. The sanguinary bite (or "kiss") of a vampire is its method of perpetuating its breed, and those rising from the dead to become vampires are subject to the will of the vampire that originally bit him/her. The bite of the vampire is usually detected as two small but swollen puncture wounds; often referred to as "the Seal of Dracula". Most vampires prefer to attack victims of the opposite sex.

Many scholars, vampirologists, and vampire hunters alike believe that vampirism is a kind of "supernatural disease", for which there is no known cure. It has been long theorized that the vampire's bite deposits a kind of enzyme found in the vampire_s saliva into the bloodstream of its victim. If the vampire draws too much blood to cause its victim to expire, the enzyme triggers a metabolic change in the victim's body, beginning with the production of a strange dark-green liquid called "ichor" within the victim's bloodstream. In about three days, there is enough ichor to nourish the victim's body the way that blood once did. If the "host-vampire" is not properly destroyed within this three-day period, the victim will return to "life" as a vampire.

Available at "The Fiendish Field Guide"