In J. R. R. Tolkien's fantasy writings, the term vampire is used loosely to designate mysterious bat-like creatures serving Morgoth and Sauron. Almost nothing is known about them, though Tolkien does name one: Thuringwethil. Sauron also took the shape of a vampire on at least one occasion, while he still had the ability to change his shape. They may have been fallen Maiar as was Sauron. They are mentioned in The Silmarillion. Whether the vampires survived the First Age of Middle-earth is unknown but they are not referenced in Tolkien's later writings.
Tolkien may have just chosen the word "vampire" for its modern connotations of bat-associated monsters. A similar instance is the use of the word werewolf by the same author to denote wolf-like creatures, otherwise possibly unrelated to traditional werewolves. However, in the context of the word "Vampire," Sauron did assume the form of such a creature numerous times. On one occasion, he flew over the forests "dripping blood from his throat." Furthermore, the vampire Thuringwethil, as her name denotes, was a "woman" of shadow.
Adaptations
The new Games Workshop The Lord of the Rings Strategy Battle Game supplement, Ruin of Arnor, has a vampire in it - Gûlavhar, the Terror of Arnor. This is a non-canonical creature, designed by Mat Ward (writer of Ruin of Arnor), Roberto Cirillo (concept artist) and Trish Morrison (sculptor). The massively multiplayer online role-playing game The Lord of the Rings Online: Shadows of Angmar features humanoid bat-like creatures called Morrovals, who appear to be inspired by Tolkien's vampires.