The vampire is Man's triumph over Nature, as well as our return to it. In creating these superhuman beings, we achieve a more perfect balance between savagery and sophistication. It That Flies by Night will be pleased by our efforts.
True vampires are extremely rare, as they are known to be created from humans rather than born. Vampires must consume human flesh, blood, and bone in order to survive, but are different from common ghouls in that they retain most of their human features and can pass as one of their prey. Also numbered among the vampiric species are fledgelings and lesser vampires, but this work does not concern them.
Vampires are created through a ritual sacrifice to a Lesser Old One (whose true name cannot be given for fear of driving the author of this text to madness) wherein the vampire-to-be's heart is violently removed from the chest of the still-living victim. It is possible that this aspect of the ritual was appropriated by Westerners who read lurid accounts of Aztec ritual sacrifices and adapted the procedure for their own purposes. Not all of the rituals are successful; it seems that only the most vigorous specimens will turn into a sapient and autonomous vampire, as opposed to A) a lowly ghoul or B) an inanimate corpse or C) an unspeakable and mindless horror.
Vampiric creatures have existed in the myths and folklore of the world for millennia, exemplified with the Russian upyr and the Albanian striga. It is possible that some of these legends are based in fact, but the author's knowledge is, alas, limited to what is available in the libraries and archives of Berlin.
The connection between Aztec ritual sacrifice and what we know of the current method of the creation of vampires is an interesting one, but it is unlikely that the Aztecs (known in their own language as the Nahua people) created vampires; Cortés' account makes no mention of any blood-drinking creatures of the night during the conquest and subsequent genocide that he conducted in what is now Mexico. Within the few Nahuatl texts that survived the missionaries' pyres, there is some mention of the tlehuelpuchi creature which drinks the blood of infants at night—but as these Nahuatl texts also claim that this being detaches its upper body from its legs in order to turn into a turkey vulture in pursuit of new victims, this author puts little stock in the tlehuelpuchi being anything more than a bit of local folklore.
Vampires are created from humans and thus appear very similar to them. Notably, they have no heart, but a token of their creator beats within the cavity and serves the same purpose as the life-giving organ. A vampire's body temperature is typically 101 degrees Fahrenheit (38 degrees Celsius), and the eyes are feverishly bright. Hair and nails continue to grow as normal, and all bodily functions and psychological faculties are preserved.
Whether the transformation has rendered a vampire incapable of sexual reproduction is unknown to this author. They seem to be immune to most human illnesses, but this is still being tested. They can see in the dark as well as a cat if not better, and an oil made from crushing the root of Valeriana officinalis seems to have a calming effect on the mind. Their eyes have an animal shine in low light. They possess strength and speed far superior to that of humans.
Vampires are weakened and sickened in direct sunlight. They cannot enter human homes, buildings of worship, or places with hallowed ground
(such as graveyards) without an invitation from a human; the reason behind this is unknown. Silver weapons cause them greater pain than non-silver ones, but they can be harmed by either.