"They came through the walls. We fought them with all we had... but they came through the walls."
- — Sergeant Nestor Roderic, Sceadu Angel 9th Regiment
A Khymera (pl. Khymerae), are terrifying creatures, literally born from an intelligent being's nightmares. They spawn in the Warp or on Daemon Worlds, coalescing into existence like malignant cysts around the psychic energies that fear and terror leaves in the Immaterium. They do not form at the whim of the Chaos Gods nor do they appear to be fragments of these powers.
Taxonomists of the Ordo Malleus classify them not as actual daemons but as Warp creatures, one example of the many unnatural flora and fauna existing in the Immaterium, though this distinction is usually lost on those facing the beasts.
Khymerae lack a proper corporeal form, allowing them to flicker between realspace and the Sea of Souls at whim, appearing momentarily before a foe and then vanishing suddenly to launch an attack from an unexpected direction.
Their phasing powers also mean Khymerae can appear inside areas thought secure -- such as locked rooms or the fighting compartments of armoured vehicles. They have even been known to appear inside of moving voidships, meaning they were either drawn by on-board psykers or were directed in the attack by agencies unknown.
Khymerae are among the creatures tamed by the Drukhari Beastmasters, technically members of the Wych Cults, though they are always male and remain remote from the true Hekatarii. Some Imperial savants who know of such things suspect they are part of an ancient Aeldari shamanic tradition, for when the Beastmasters go to battle, they wear totems and masks echoing the nature of the alien predators under their control.
It is partially because of these artefacts that they enjoy such mastery over their ferocious beasts, for their masks harbour complex sonic emitters and pheromone traps. The Warp-beasts called Khymerae are living proof of the Beastmasters' skills as a spirit-hunter.
Beastmasters must hunt down and harness their own Khymerae in perilous fugues or dream-quests, but if they are successful, they can draw entire packs of Khymerae back across the veil to the physical dimension to do their bidding. Khymerae set loose on the battlefields of realspace can wreak utter havoc before fading away like mist.
Khymerae of the Koronus Expanse
Those Khymerae encountered in the Koronus Expanse usually have a huge, roughly feline form, best likened to a skinned Terran hunting cat. Each appears as a slightly different assemblage of skinless flesh, mighty jaws, grasping talons, and powerful limbs. The bright red muscles glisten wetly no matter the level of illumination, while the bare bone of the skull sports several pairs of flat black eyes. The long black tongue appears segmented, as if it was an immense worm extending from the Khymera's mouth.
Two great raptorial arms sprout from the shoulders, some linked by thin strips of red muscle and white sinews and lined with impaling spikes. Others have more tentacle-shaped whips of serrated flesh, and can lash out with blinding speed to catch prey. Much smaller talons are found on the chest, where they are used to rip small bits of flesh from a downed victim, while the tail is a fleshless series of bone links.
Some survivors have reported even more bizarre shapes with bulging eyes and tusked jaws lacking the dorsal talons; it is supposed these may be immature variants or creatures formed from unnatural xenos nightmares. The entire effect, though, is always one of noisome unnaturalness and cannot be mistaken for anything but a Warp-spawned creature of Chaos.
Khymerae are pack hunters and are often found in small groups of four to eight, but in areas of great psychic disturbance can appear in vast hordes of forty or more. They fear little and normally view everything, even other Warp creatures, as prey. While they do not display any actual sentience, they do show great cunning in their actions while hunting.
Their usual tactic is to rush in as quickly as possible, leaping over or phasing through any obstacles they encounter. Once a Khymera closes with a desired target, it quickly lashes out with its raptorial arms, seeking to snare its prey with the sharp spikes.
The Khymera then drags its victim within range of its long-fanged jaws and smaller chest talons. However, the Khymera does not spend too much time on any one target and quickly moves on to a fresh victim, seeking to spread as much fear and terror as possible within a short period of time, feasting on the psychic emanations it produces.
It is in this way they reproduce, using these terrifying attacks to spread new nightmares and other strongly emotional reactions, from which new Khymerae can emerge. Once they have glutted themselves on their kills, the Khymerae fade away, rejoining the Warp which birthed them.
While often found in the vicinity of open Warp Gates and similar manifestations where the barrier between the Immaterium and realspace is weak, Khymerae can also appear far from any known Chaos incursions. There are many tales throughout the Expanse of cruel Drukhari using these creatures as part of hunting packs or raiding parties, somehow controlling the unstoppable ferocity the beasts normally display. Some even quietly speculate these xenos may actually capture Khymerae in the depths of the Warp or other shadowy realms, conquering their will and enslaving them to their new masters.
Regardless of how they came to be under Drukhari control, in these situations the beasts are even more dangerous than usual as their handlers can direct their fury to best advantage. Where they might normally rampage in wild pursuit, here they can be aimed at the foe so as to cause maximum carnage and casualties.
They can also be used as tracking and hunting animals, loping across huge distances and warping in and out of realspace at a tremendous pace. It is nearly impossible to hide from a Khymera on the hunt, as walls, bastions, bulkheads, and even voidship hulls do not slow them in their quest.
Khymerae can also be found in the Koronus Expanse wherever powerful and long-lasting psychic impressions have been formed. Battlefields, places of massacre and slaughter, torture chambers, and similar locations all may have seen sufficient fear and suffering to cause the creation of one or more Khymerae.
Some Inquisitors who covertly roam the Expanse have also reported tales of powerful psykers, especially those unstable nascents still lacking full control of their abilities, accidentally summoning newly-formed Khymerae from the Warp. The psyker's nightmares that resulted in the spawning of the Warp creature are trivial compared to the actuality of the Khymera, now given physical form and eager to meet its creator.
In the 3rd Edition of Warhammer 40,000, the Khymerae were known as "Warp Beasts," beings valued by the Drukhari Wych Cults as living weapons who were the embodiment in the Warp of the fear and terror that they inflicted upon their captured slaves.
These Warp Beasts were vicious predators who would attack any living being within range. They were usually placed under the control of a Wych Beastmaster to ensure they only attacked the intended targets.
- Codex: Dark Eldar (5th Edition), pg. 30
- Codex: Dark Eldar (3rd Edition), pg. 9
- Rogue Trader: The Koronus Bestiary (RPG), pg. 13
- Games Workshop Online Catalogue - Dark Eldar Khymerae