A Vampire, also known as a Vrykolaka, a Strigoi or a Nosferatu in ancient Terran lore as well as in different regions of the galaxy, is a member of an intelligent species of other-dimensional entities that have the ability to appear to others in any form they choose, and are native to the psychic realm of the Immaterium. They became entrenched within the legends of Old Earth and were later regarded as being discredited myths as well as legends. In reality, the Vampires of legend were real beings who infiltrated many societies across the galaxy where they masqueraded as their chosen race and sought positions of power. They are polymorphic parasites, preying upon the lifeforces of their host species.
The ancient legends of Old Earth concerning Vampires were for long ages discredited as invention, folk-lore and myth. The reality, however, was to prove far more disturbing. Vampires are polymorphic entities able to radically alter their metabolism in order to resemble the creatures amongst whom they dwell. Their natural shape (if such it can be called) is bat-like, although approximately human-sized. Vampires exist within the societies of most of the established intelligent races of the galaxy, and often assume positions of authority. They naturally crave power amongst the intelligent races, regarding even fellow Vampires as threatening rivals. They have no known homeworld. Where they evolved and why they have come to occupy a parasitic position within alien societies is unknown.
Vampires live amongst their chosen race after the manner of that species, and cannot easily be singled out. They have psychic powers of a level comparable to that of humans. Vampires maintain their lives by absorbing the lifeforce of other creatures, achieved by prolonged physical contact. Fortunately, Vampires can derive some sustenance by normal eating and drinking, and so only require a little stolen vitality to survive. If a victim is drained of his or her lifeforce they can be revived as a Zombie, a will-less servant completely under the Vampire's thrall. Zombies are undead corpses, and will slowly rot and decay until their usefulness becomes somewhat limited. Creating a Zombie is not something casually undertaken.
At some point in the 41st Millennium, a Warp-spawned Vampire and its servants had risen to power on the Imperial Hive World of Cephian IV. The Black Templars Chapter of Space Marines is known to have battled the creatures, with the future High Marshal Helbrecht slaying the entity, and through this act earning induction into the ranks of the Sword Brethren.
- Codex: Black Templars (4th Edition), pg. 44
- Warhammer 40,000: Rogue Trader Rulebook (1st Edition), pp. 205-206