GURPS - TrueBlood
The vampires in the universe reveal themselves to the world as being actual, and not mythical, beings after Japanese scientists develop a synthetic blood product that provides adequate sustenance for vampires and allows them to not have to feed on human blood.
Reaction to the vampires’ Great Revelation is mixed. Islamic countries dish out death and torture to the vampire population, while nations such as Bosnia, Argentina and most African nations just simply refuse to acknowledge their existence. Some nations, such as France, Italy, and Germany, acknowledge the vampires, but they do not torture them nor do they give them the rights of citizens. The United States, Great Britain, Mexico, Canada, Japan, Switzerland, and the Scandinavian countries are more tolerant; however, even in the USA they are not permitted certain rights like the right to marry.
Rather than acknowledging the legend that vampires are deceased humans that have risen from the dead to prey on the living, the vampires insist they are simply the victims of a medical condition that makes them allergic to sunlight and affects their dietary needs.
Vampires are pale and cold, possess unfathomable strength as well as speed, and have keen senses of hearing, smell and vision. This makes it easy for them to protect themselves. They have the ability to remain completely still, expressionless and silent. Vampires can control the minds of humans (glamour, often seen as a form of hypnosis), and a few can even fly; individuals may have other powers and abilities.
Vampires’ fangs come out when they are hungry, see blood, are sexually aroused, or when they need to fight. A vampire is compelled to obey his or her maker. The visages of vampires do not age. They can survive and recover from most forms of physical injury, but they will die if staked, exposed to sunlight, completely drained of their blood (if not treated promptly), or decapitated. Silver is highly toxic to them. Unlike the vampire mythology of other universes, crucifixes have no effect on vampires in the universe, garlic only produce allergic reactions on them, and most (except the “very old ones”) are able to enter places of worship or step on “holy-ground”. They cannot enter a home unless invited and once they have been uninvited, they must exit the premises.
The “cult following” of humans fascinated by vampires (see Fangbangers) includes volunteers willing to be bitten to provide fresh blood nourishment to vampires. If a vampire and a human share blood (each drinking from the other), it will form a blood bond, linking the pair’s psyches. Vampire blood without exchange is sought after by humans as a drug that can enhance strength, heal wounds, and increase attractiveness, among other effects. Due to the shortage of willing vampire donors, human " Drainers " attack vampires and drain their entire blood supply, either staking the vamps or leaving victims to die in the sun. The blood is then sold as a drug in vials on the underground market. It can be highly addictive, but may cause psychotic or murderous rampages by human users upon the first use, and it is highly unpredictable who will be affected in this manner.