Kroot

"They are fierce indeed these Kroot, and savage. I look upon them and tremble at their ferocity. I can only hope that when the enemy sees them they tremble as I do." — Por'Vre'Tau'Cho, Water Caste Envoy to Sy'l'Kell prior to the ambush of the 17th Brimlock Dragoons

The Kroot (Krootis aviana), also designated by the Imperium as Kroot Carnivore, are a xenos species of savage humanoids who are members of the T'au Empire. The Kroot evolved from avian creatures on their homeworld of Pech. Kroot are tall (a good half-metre taller than most Humans), their avian ancestry giving them a bird-like beak and long quills protruding from their heads like hair. Smaller quills, possibly the evolutionary remnants of feathers, can be found scattered over their bodies. A unique feature of the Kroot is that they evolve by selecting genetic traits of their defeated foes to absorb by eating them. 
Due to this, the many Kroot warbands across the galaxy often look radically different. Kroot leaders are known as Shapers; they are generally the Kroot with the best ability for recognizing desirable traits in defeated foes and tell their kindred (the word for a Kroot clan) what to eat to reshape themselves to suit the task at hand. For instance, a Shaper who wants his Kroot to gain muscle mass will campaign against Orks to acquire the suitable DNA, while extensive feeding on flying predators will allow the Kroot to grow wings. This eating of their foes ties in with the religious beliefs of the Kroot: they believe that when a warrior of any race dies, his warrior spirit should be kept, and the only way to do this is by eating his flesh. The Kroot practice this in their "burial" customs, in which the body of the deceased is consumed by the kindred. Kroot, who prey extensively on a particular species, will begin to take the characteristics of that creature. In sentient species such as Orks and Humans, they may take on cultural aspects of that people as well. Kroot, who have fed on Drukhari, for example, soon begin to show signs of the cunning and intense cruelty the Drukhari are known for.
In the case of animals, this sometimes leads to evolutionary dead ends. A kindred will find itself locked into an animalistic and unintelligent form, unable to evolve themselves any more. Species such as Tyranids who also absorb the DNA of their prey are hazardous for Kroot to prey upon, as they may acquire too many undesirable Tyranid characteristics. The ecology of the Kroot homeworld of Pech includes many species of animal that are partially Kroot, the results of a kindred's evolutionary missteps. The Kroot use these related creatures as labourers, pack animals, and even as weapons. The most common examples are the canine Kroot Hounds, the lumbering and powerful ape-like Krootox, the dromaeosaurid Knarloc riding beast, and the massive, dinosaur-like Great Knarlocs. Another creature of note is the Kroothawk, an animal held sacred by the Kroot, possibly because it may be their evolutionary ancestor. There are other Kroot sub-species that are considered outcasts in Kroot society and are killed by Kroot if found.
In order to gather genetic material from all over the galaxy, the Kroot offer themselves as mercenaries and sell their services to anyone willing to pay them. They travel the galaxy taking limited contracts from both major and minor intelligent starfaring species and are regularly employed by the T'au. While the contract with the T'au is supposed to be an exclusive one, the Kroot regularly send out their warspheres to continue their mercenary trade amongst the wider cosmos.

Basic Information

Anatomy

The Kroot originated on the world of Pech and, though their anatomy is humanoid, there is evidence to suggest that the roots of their evolution likely lie with that world's avian analogues. Kroot retain vestigial beaks and have a light, almost hollow bone structure, with four digits on each hand and foot.
Kroot skin is rough with small, barbed spines, similar to the elongated quills on their heads, protruding from various locations on their flesh. Skin pigmentation ranges from earthy brown colours and dappled greens to vibrant oranges and everything in between. Depending on the feeding directions of the Kroot Shapers, the colouration of each kindred can vary quite considerably.
It is also common for Kroot from each kindred to have particular tribal markings painted onto their skin. Kroot mature quickly, with their most rapid period of growth occurring in the first ten Terran years of their lives. By the age of twelve Terran years Kroot are considered adults, and it is not unknown for Kroot to live to over a hundred Terran years old, their skin becoming increasingly pitted and leathery in their last few years of life.
Kroot are tall, and their bodies have a wiriness to them that appears deceptively fragile. In actuality, Kroot musculature is extremely powerful and composed of dense fibre spindles with a greater power‑to‑mass ratio than is found in Humans. Swift muscle contractions create a whiplash effect, allowing the Kroot to deliver powerful blows with great rapidity.
The Kroot tend to move on the ground with a bounding, hopping gait, but in dense forests, they can spring from tree to tree at great speed. The Kroot favour primitive garb: harnesses worked from the hides of animals and adorned with bones, handcrafted amulets and circlets.
The limited specimens that have been made available for study by Imperial savants and the Magos Biologis of the Adeptus Mechanicus have possessed brains composed of a front and rear hemisphere. It appears that the larger frontal hemisphere controls the functions of logic, reasoning and memory while the rear, less developed hemisphere is more attuned to imagination and creativity. If this is indeed the case, it would go some way to explaining the pragmatic approach to life of the Kroot and their current technological stagnation.
The Kroot head is crowned with a great mass of tough, flexible quills that appear to be a part of the Kroot's sensory apparatus. These quills contain what seem to be ganglia running from the frontal lobes of the alien's brain and, in this position, would be extremely efficient at receiving and interpreting information on the surrounding environment.

Additional Information

Perception and Sensory Capabilities

The olfactory cavity within the Kroot skull is also enlarged, with multiple sense organs within both it and the mouth. Their eyes are without pupils and generally a milky white. 
It is likely that they are able to see further into the infrared end of the spectrum and can sense the body heat generated by their prey. Therefore, the Kroot make excellent trackers and would be extremely difficult to sneak up on.
The Kroot generate little in the way of waste, as their bodies excrete metabolic waste in the form of a pungent, oily sweat that has a variety of properties, depending on what the Kroot has consumed. The most apparent benefits are that this sweat appears to be heat-retardant to a degree, has antibiotic properties and can cause a poorly-aimed blow to slide clear. It is suspected that the Kroot can alter the properties of this secretion in order to leave pheromone trails, mark territories, provide warnings to their fellow Kroot and even communicate with one another through scent.
This may also be some form of biochemical control that extends to lower life forms such as other avians and animals, as there is evidence to suggest that the Kroot employ empathic pheromones to prevent such creatures from being startled by them and giving away their position in battle.
Combined with this method of communication, the Kroot can learn new languages at an astounding rate, matching posture and tone to the sound of foreign words in order to discern their meaning. Their own verbal communication is a mixture of clicks and whistles, possibly reinforced by these pheromone excretions.

Civilization and Culture

History

War in the Place of Union

At the close of the T'au's First Sphere Expansion, an exploration fleet out of Dal'yth picked up long-ranged scans of Ork warships firing on Kroot Warspheres. The previously unencountered Kroot were defending their enclave on the planet of Krath, although they were hopelessly outnumbered. Intending only to observe, the T'au were drawn into the battle as both the Air Caste admiral and Fire Caste commander could not bear to watch the honourless Orks bludgeon their way to victory. Quickly deploying their superior fleet, the T'au destroyed the ramshackle Greenskin ships. Too late, however, they realised that this was merely the vanguard of a mighty invasion force that was closing on them in an encircling pattern. Thus began an extended war, both in space and over several planets, later named the War in the Place of Union, for it marked the first time the T'au and Kroot fought side by side. So effective was the sudden alliance that they withstood the Orks long enough for reinforcements from Sa'cea to arrive and ultimately triumphed over the Greenskins.
The T'au were so impressed with the Kroot's fighting prowess that they agreed to extend the alliance to liberate the remainder of the Kroot enclaves, who were also under Ork attack. For the next ten Terran years, the T'au helped drive all sign of Orks from the Kroot worlds, eventually coming to their homeworld of Pech at the behest of the greatest of Kroot leaders, the legendary Anghkor Prok. There, at the sacred Oathstone, the Kroot leader swore allegiance to the T'au Empire and pledged his warriors to fight for the Greater Good (and regular payment). That pledge, and the cooperation between the two species, is still honoured today. The Kroot are, by far, the most common alien auxiliary force to serve in T'au armies.
The T'au greatly value the military service of the Kroot, although they continue to hope that exposure to their own superior culture will eventually cure the Kroot of their cannibalistic tendencies.

First Contact with the Imperium

The Kroots' first encounter with the Imperium of Man came during the Damocles Gulf Crusade on the world of Sy'l'Kell. Troops of the Astra Militarum's 17th Brimlock Dragoons were in transit to the front lines from their landing zone when they were ambushed by Kroot kindreds. The column's forward scouts were eliminated by Kroot Carnivores before they could get a warning off to the regiment following behind. As the main body of the Brimlock 17th pushed through a narrow forested defile, the Kroot fell on them. Three Kroot kindred were involved in the attack. The surprise was complete, and scores of Imperial Guardsmen were killed in the opening moments of the ambush.
Colonel Konstantin Griffin and Commissar Eigerman quickly recovered and held the Imperial line long enough to fight clear of the Kroot's trap. From then on, the column was continually harried by the Kroot until Colonel Griffin linked up with the Space Marines of the Scythes of the Emperor Chapter. With the arrival of the more powerful Astartes forces, the Kroot realised that they were overmatched and withdrew to seek easier targets for their guerilla tactics elsewhere.

Scientific Name

Krootis Aviana