In the RPG Rifts, a Vampire Intelligence is an entity responsible for producing Vampires.
Physically, a Vampire Intelligence is a mound of slimy flesh up to a hundred feet across, with dozens of tentacles protruding, and a large eye in the center, surrounded by hundreds of other eyes.
The way that the Vampire Intelligence works is by finding an evil human who is willing to take a fragment of the Vampire Intelligence and become a Master Vampire. The Master Vampire then creates more Secondary Vampires, who go out and create their own Vampires. And when any of these Vampires kill anyone, the Vampire Intelligence takes a cut, as it were, of the psionic energy caused by their death.
A Vampire Intelligence may have dozens of Vampires in different dimensions, and may magically teleport between these dimensions, into special layers deep underground that provide the Intelligence with magical energy.
If a Vampire Intelligence is killed, all of the Vampires created by it or its creations disappear. Thus, killing a Vampire Intelligence is a very desirable thing to do. It is also very hard. The Intelligence must first be weakened, and then attacked continuosly by magic, silver or wood until it is dead. Since these are massive entities, with hundreds of tentacles, magic and psionic powers, and usually hundreds of guards, this is almost impossible for anyone less then a Dragon or God.
It is hinted that the Vampire Intelligences are related to the Old Ones, extremly powerful intelligences that were locked into mystic slumber ten thousand years ago. The Vampire Intelligences were ignored because they so (relativly) weak.