The Ak'Haireth or Bone Drinkers, were a fungoid Xenos species that was a bane to the Imperium during the Great Crusade. These parasitic sentient lifeforms who operated as psychically interwoven gestalt Blooms, and sustained themselves by slowly and agonizingly feeding on any animal life. Human bone marrow in particular was a favorite target. The species operated at the edge of Segmentum Solar, inhabiting scavenged ships of other species and raiding isolated colonies and Feral Worlds to feed on unprepared populations. They were also a threat to the early Human settlers of the Askellon Sector.
The Ak'Haireth were resilient and able to always return despite genocidal campaigns by the Space Wolves and Night Lords. However in the Hunting of the Ak'Haireth, Alpharius and the Alpha Legion were able to deploy a deadly biological weapon and drive the species to extinction.
- 1: The Horus Heresy Book Three, pgs. 102-103
- 2: Dark Heresy Second Edition: Enemies Without, pg. 138 - Chapter 3