Something I bashed out a while ago for an intellectual exercise. It's an in-character guide to the more common alien races, collating various bits of background as well adding some of my own observations. As a biologist I've gone into technical details about their DNA and whatnot, but I've not really bothered with organs much as Xenology covers that side of things quite neatly. I've got entries for the other major races I might stick up if people are interested.
Physiology, anatomy and biology
The unusual genetic structure of the ork is well known. They possess a dual-genome; the nuclear genome, homologous to eukaryotic DNA species, and cytosolic DNA which resembles algal/fungal species. This additional genetic material seems to be linked irrevocably with their reproductive system and also provides the ork with an alternative source of food; photosynthesis. While this is insufficient to feed the ork even under optimum conditions, it reduces the food intake considerably, a major contributor to both the large size of individual orks and their populations.
The ork reproductive system is based around sporulation, though in a way entirely dissimilar to bacterial models. Orks ‘spores’ are microscopic and combine the characteristics of seeds and blastocysts. Once a spore finds a suitable location, fruiting bodies will continue reproduction while the adult ork grows underground. Depending on local conditions, this process can take anything from months to years. Smaller greenskin subspecies (gretchin, squigs) undergo an identical system but with a shorter gestation. These species will emerge first to pave the way for the ork climax community. It is believed the weak psychic network to which orks are attuned is active in this fungal stage, and it has been postulated as a method of communication to ensure a stable population is grown.
Orks possess a ‘genetic memory’ – rudimentary skills and even speech develop exceptionally quickly in newborn orks, taking only days to manifest fully. Many orks seem to be born with specialist skills, most notably the ‘mekboy’ caste responsible for the construction and maintenance of ork equipment. That they understand the process on only an instinctive level is well documented and is considered the ultimate proof that orks were not created by natural evolution. Theories that ork leaders are a specialist leadership caste are intriguing, but improvable.
The aforementioned psychic network is present in all orks. It is a much weaker and safer connection to the warp than that of any human psyker, and seems to play a role in ork society as impetus to war and migration, though this is poorly studied and the propensity for large ork populations to begin a ‘Waaagh’ is more likely simply a result of depleting natural resources . Ork psykers, more attuned to this energy, are rare and usually short-lived, but are capable of brutish and destructive psychic displays before they are killed by backlash.
Experiments using herbicides and fungicides have shown great success against orks, though of course such toxins are deadly to most carbon-based life forms in sufficient doses. The mass production of biological weapons based on such poisons has been recommended to the Administratum – orks are a constant threat, and excess poisons can be used against other enemies (despite being of lower efficiency) or in agriculture.
The ork mind is famously simple. They live to fight; the everyday life of the ork is built around violence, ranging from displays of dominance over smaller orks and greenskins through contests of strength and duels up to open warfare itself. Orks will follow only those who prove themselves to be stronger, meaning ork ‘society’ is ruled by force of personality and force of arms.
Orks will never shy away from a fight, even when it is medically or tactically unwise to do so. They do not approach violence with malice or hatred, but with an almost childish enthusiasm and glee. While orks do seem to feel pain on some level, they are unmoved by it. Efforts to torture orks are entirely pointless. Equally, orks have no fear of death. In spite of this, battlefield reports tell us that orks have been routed many times over. This presents a conundrum, but not a difficult one.
Ork society is based around strength. The only goal is to become stronger. To be defeated in battle is to be weaker, the only thing damaging to ork morale, and they flee so that they may regroup, recover and attack once more. It is not for naught that Yarrick took to wearing his cumbersome claw, or that in the jungles of Armageddon soldiers daub their skin green and mimic their prey – this is the only form of psychological warfare that will have any real effect.
Orks are extremely fond of fighting at close range, as it allows them to engage in melee, an area in which they are known to excel. Engaging from a distance, especially the use of artillery and orbital strikes, is an excellent method often neglected by orks themselves.
Their fondness for violence can easily be manipulated by any commander worth his salt. Orks will almost always pursue a fleeing enemy and can be easily draw into traps, crossfires and pincer movements. Similarly, large armies tend to be made up of smaller warbands who can be enticed to engage alone, allowing Imperial forces to face a potentially large and devastating horde piecemeal, as a series of smaller threats.
Orks may be barbarians, but they are not animals. They are capable of learning and their leaders have considerable hands-on tactical experience. Many a soldier has learned too not to underestimate the ork- many ork warlords are all too aware of these tactics and have been known to outwit Imperial commanders, an ignominy far greater than the defeat and, in many cases, execution that will follow.
This problem can be countered by eliminating said leaders, which will cause a power struggle between subordinates for control of the horde. These can take anything from days to years and ork armies have been known grind to a halt as they battle amongst themselves. The threat, while not eliminated, becomes much less urgent, allowing Imperial forces valuable time to redeploy and resupply. Locating and even merely identifying ork commanders can prove difficult, however, and multiple efforts may need to be made.
Physiology, anatomy and biology
Tau are unremarkable physically, biologically or genetically. Their genetic/cellular structures and internal organs are similar to those of mankind, though inferior, and other species. Their reaction times are slower, lifespan considerably shorter (tau telomeres are notably unstable) and they are better adapted to digesting plant matter. Physical evidence suggests that the tau evolved from herbivorous ruminants which, for unknown reasons, shifted to more omnivorous diet. Tau vision is less adept at seeing and distinguishing colour, especially towards the lower end of the spectrum, but apparently capable of seeing into the ultraviolent frequency. It has been postulated that the plants they ate used ultraviolet signals to attract the herbivores, which could be used for their own reproduction. Their olfactory senses are also considerable, no doubt a remnant from a time when detecting the scent of predator meant life or death.
Tau possess a herd mentality owing to the aforementioned evolutionary past. As with the eldar, superficial similarities have led to Imperial commanders and forces mistakenly anthropomorphising or, worse, empathising with the aliens. Their entire society would be almost impossible for mankind to emulate, a notion as laughable as it is heretical.
Tau society is restrictive, prohibitive and rigid, at least to an outsider, but tau understand and accept their place within the herd without question. The tau have extreme difficulty in understanding that other species do not share this trait and do not wish to join their ‘herd’ for mutual protection – it could be reasoned that their bizarre philosophy is entirely a product of their biological history. At least, if not for the Ethereal caste.
What little we know of tau history reveals the four main castes were once four great nations - rival herds - who fought a long and bitter war until the Ethereals ‘appeared’ and convinced them all to work together for –what else – the Greater Good. Their history has been infused with myth, clearly, but the Ethereals are the sheepdogs, the cattleprods of tau society. Few have been successfully recovered, but evidence gathered from those few suggests pheromonal signals may make tau around them more pliant. This alone could not cement them as absolute rulers, but when combined with an education system in which Ethereals are revered as something approaching angels or demigods the apparent stability of tau society is explained.
One epidemiologist suggested creating a tailor-made disease that would affect only Ethereals – a foolish notion, as it would more much difficult to create than a disease which affected all of the tau castes and considerably less useful. The notion of ‘attacking the Ethereals’ is not without merit, however; the morale damage to tau forces after the loss of such individuals is catastrophic.
One ‘Commander Farsight’ defied the Ethereals and created a tiny secessionist empire in the region of space known as the Damocles Gulf. There has been no subsequent contact with tau or Imperial forces, but this show that the tau ideals can be eroded. There is a karmic justice in such a thing – the tau are fond of propaganda and gladly proselytise, and many fools have been led into heresy and xenophilia by the honeyed lies of the greyskins.
Tau technology is notably sophisticated – the Imperium first noticed the tau at an iron-age level millennia ago, but warp storms prevented their summary destruction. In the intervening period tau technology has advanced at an alarming rate, in some disciplines equalling or even exceeding Imperial science.
Tau prefer a short and mobile war, relying on their powerful technology to maintain a highly mobile army. Their military strategy seems based mostly around ambushes and decisive strikes, at which the elite warriors of the Fire Caste and their powerful weapons excel. This over-specialisation reveals a weakness, however. The tau have little stomach for protracted war, as their biological inferiority and the difficulty in repairing their advanced technology quickly become apparent. Imperial commanders should dig their heels in and force the tau to fight a slow, bloody campaign.
As with all enemies, the elimination of key commanders is a primary concern, but in the case of the tau it is especially important. The death of an Ethereal has been known to end a war, and due to their short lifespan the removal of their older and more skilled commanders (who have proven on many occasions to be formidable tacticians indeed) means a general will quickly find himself fighting an army led by a child who learned more of war from a book than a bayonet.
The tau prefer to fight a war at range. They consider melee combat brutish and barbaric. Close combat specialists, such as guardsmen from feral worlds, can tear apart tau cadres if they are able to close the distance. This is difficult, however, as the tau are fine logicians and seldom make war without considerable orbital and aerial support.
The last, and most important, consideration when facing the tau is one of ideology. The tau wage an ideological war, and while the Fire Caste are little more the ruthless killers, the tau propaganda machine does not cease even in times of war. Promises of a better life will entice more naive and weak-minded soldiers, especially after during the hardships of war, so Commissars and commanders must be vigilant lest they fall victim to the dishonour of desertion or even insurgency. Tau sometimes deploy human auxiliaries, which should be prioritised as targets to stiffen resolve.
Physiology, anatomy and biology
The kroot are an extremely strong species in spite of what appear to be a slight physique. Muscle fibres are tightly bundled, providing greater strength than human beings without a manoeuvrability trade-off. Kroot do seem to produce very little by way of fat cells, and their musculature is very energetically demanding, meaning kroot must eat an unusually large amount of food for their size.
The kroot hunger for flesh is well known. Eyewitness describe them feasting on the corpses of the fallen; ally, enemy and even kin. The reason for this is perhaps one of the strangest xeno adaptations witnessed by Imperial scientists, and the veracity is being hotly contested even now. Nonetheless, evidence suggests that the kroot are able to derive some of the strengths and abilities of the prey in a literal, biological sense rather than the assumed spiritual significance commonly seen in tribal societies both human and xenos.
The complex genetic methods behind this are, as yet, unknown, but could prove revelatory. The greatest enigma is how such a mechanism could evolve; it appears to be, at a glance, extremely counter-intuitive as most of the prey the kroot consume will be inferior to them, and a repetitive diet would spell certain doom. It is this fact which has propelled them into a mercenary lifestyle. A stationary, ‘stable’ kroot population will eventually become perfectly adapted to the environment and barely distinguishable from local fauna. It is believed that a mass extrinction event of the kroot homeworld favoured this trait, allowing the ancestors of modern-day kroot to speciate and dominate. Many kroot ‘subspecies’ like the krootox and kroothounds have undergone rapid allopatric evolution to create a working ecosystem, a biome in which the kroot themselves are unique because they prefer to control the direction of their own evolution, allowing them to rapidly adapt to changing conditions. It is the role of the ‘Shaper’ leadership caste to regulate and control the diet of their kin, ensuring that the kroot retain phenotypic plasticity.
The military potential of this vile hunger has not gone unnoticed by the Inquisition. Efforts to poison bodies have proven ineffective, however, due to the advanced olfactory capabilities of the the kroot. Rotten flesh is similarly ineffective. Kroot prefer fresh meat, but if starving they will accept spoiled food sources - their stomach acids are extremely potent and kill most microbes.
More imaginative methods of ‘body-poisoning’ have been investigated, using a variety of costly and supposedly odourless toxins, amino-dextro and even irradiated meat, with varied success. The lattermost lead to the discovery that kroot can detect medium-to-high levels of radiation. Expense renders the use of the few effective measures almost useless in a battlefield scenario, however. Bodies are best used as bait, though the kroot are wary of such tactics.
Culturally speaking, the kroot are not an advanced species; in spite of their interstellar travel (posited to have been stolen, via ingestion, from ork ‘race-memory’) they still lead a strictly tribal lifestyle. The main concerns of the kroot remain survival and honour and their mercenary lifestyle is primarily about finding new genetic strength. The kroot have a crude animistic belief and few morals – as would be expected of a race of cannibals and corpse-eaters – and will fight for almost any employer willing to pay them (usually in technology and meat). Some Imperial commanders have been known to make use of kroot mercenaries, a despicable practise that must be stopped at all costs. They are primarily encountered as a part of Tau forces, as their homeworld is a protectorate of the empire, but few seem to care about, or perhaps even understand, the Tau’va philosophy.
Able foragers, kroot can live off the land extremely well, making efforts to cut supply routes all but useless. Kroot are best suited to jungle warfare where their ambush and melee skills are best put to use. On more open battlefields their crude firearms and disdain for armour are no match for Imperial firepower. In their preferred environment, the use of firebombing and flamers is strongly recommended to burn the savages out. It should be noted that kroot have never been observed to fight under their own banner and will always be in the employ of another faction, either as a separate, specialised platoon or auxiliaries, labelling them a minor xenos threat.