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, during the travels of Beren and Lúthien, while he still had the ability to change his shape. They may have been fallen Maiar as was Sauron, lesser angelic spirits (as opposed to the Valar, greater angelic spirits, as was Morgoth). They are mentioned in The Silmarillion. These brief mentions of creatures such as vampires, werewolves and hill giants, or of non-Istari wizards, magic rings not connected with the One Ring, or even the spells and curses placed by Thorin Oakenshield and his party on the troll hoard are windows into just how expansive Middle-earth really is, beyond even what is given much detail in J. R. R. Tolkien's work. Remember that Hobbits barely figure into any histories before the War of the Ring. It is likely that he would have written more about these obscure topics and creatures if he had the time.
There is no mention of Vampires after the First Age ended, and they presumably became extinct after the destruction of Morgoth.
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 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 cannotes, was a "woman" of shadow. At any rate, we can at least assume that Tolkien was aware of the fact that vampires, while bat-like creatures, were also somewhat man in form and involved "blood" in some way or another--albeit, if not in the way traditionally viewed of such fictional creatures.
Portrayal in adaptationsEdit
Role in Computer and Video GamesEdit
The new Games Workshop The Lord of the Rings Strategy Battle Game supplement, the 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 the Ruin of Arnor), Roberto Cirillo (concept artist) and Trish Morrison (sculptor).
The Lord of the Rings Online has Carcharan, a vampire of Morgoth in the forest of Mirkwood. It is a vampire in the form of a giant vampire bat.