Ur-Ghuls are a Xenos species that are native to the labyrinth ziggurats of the Dark Eldar city of Shaa-dom.Source: Lexicanum
Their nature means that they are one of the many atavistic beings that can be recruited by an Archon for his court. These creatures are noted for being the most hideous of all the creatures that a Dark Eldar Archon can summon. Being sightless, yet quite agile, their tracking abilities are quite renowned and once a prey has been caught by the beast’s quivering scent-pits, it is known that nothing is able to escape these whip-thin horrors.
Ur-Ghul migrations are periodically purged by the Deathwatch, most notably one led by the Dreadnought Xenomortis on Plenitia.[