In the universe of Games Workshop's table-top wargame Warhammer 40,000, the Tau are an alien race , inhabiting a small but dense region of space on the eastern edge of the Galaxy, roughly 300 light years in diameter. The Tau were first introduced to Warhammer 40,000 in late 2001, the result of Games Workshop's plan to introduce a new race to the game.
The Tau have advanced rapidly since their first encounter with the Imperium of Man in the 35th millennium, rising from a hunter-gatherer level of technology to a starfaring race in less than six thousand years. Tau society has also advanced rapidly, from warring tribes to a unified caste system working towards common goals, known by the Tau as Tau'va, The Greater Good.
As well as the five castes of the Tau, multiple alien species are incorporated into the Tau Empire; the most significant of these being the Kroot and Vespid although many other races, including the space faring Nicassar and the mercenary Tarellian Dog Soldiers are members. In addition, human auxiliaries (Gue'vesa in the Tau language) are sometimes seen to be aiding the Tau as well.
The Tau were the fourth army to receive a Codex updated for Fourth Edition rules (Codex: Tau Empire - Hoare, 2006). Additional rules for the Tau appear in a Forge World Imperial Armour rules supplement (Imperial Armour Volume Three - The Taros Campaign - Kinrade, 2005).
The Tau's psychology is closely tied to their physiology, with the Tau of each caste effectively being a subspecies of the tau race. This was initially a result of adaptation to suit the environment each group of the sub-Tau species found themselves in, although interbreeding between castes was later forbidden by the Ethereals.
The Tau are humanoid in shape, although they have hooved feet and four-digit hands (three fingers and one thumb). Their skin is grey-blue (although this can vary in pigmentation between worlds), rough in texture, leathery, and exudes almost no moisture. This grey-blue coloration is due to the cobalt-based blood of their physiology, as mentioned in "For the Emperor". Their faces are flat, wide around the eyes, with an "I"-shaped indentation running from the centre of the forehead to where a human's nose would be. Tau vision is considered slightly superior to humans - their visual spectrum extends a little more into the ultraviolet and infrared wavelengths. However their pupils do not dilate giving poorer depth perception and slower focusing reflexes than Humans. The olfactory organs are inside the mouth. Physical strength and size varies between castes, with the Fire Caste being among the physically largest of the Tau.
Only two identifiably female Tau have ever been illustrated. The first, Commander Shadowsun, appeared to have a more human face than male Tau; being smoother and sleeker with larger eyes, a nose-like facial feature and a "Y" shaped facial slit. It is not known, however, whether Shadowsun is representative of all female Tau. The second, the subject of an imperial dissection, had the facial characteristics of a male Tau.
( It is also worthy to note that Ultramarine Captain Uriel Ventris captured what he presumed to be a female Tau on Pavonis, although the subject did not state it was a female, it's body features and movements made it appear so. One could take this to support the Shadowsun image as the standard for all female Tau as she also seems to show more feminine features than male Tau.)
The Tau do not possess psykers (indeed, their minds barely register in the warp at all) and as a result have little knowledge of the Immaterium beyond its existence. This gives them some level of resistance to warp-based powers affecting the mind, but it offers little, if any, protection against physically-manifested offensive powers. They are largely unaware of the perils of the Immaterium and for this reason the Tau have conducted research into the Warp on Medusa V, however, the conclusion was reached that further research was unfeasible, and that "the Warp is no place for the Greater Good and is best left to those foolhardy races who cannot pull back from that terrible realm." Also with no other knowledge of the warp none of their starships are fitted with true "Warp Drives" meaning that all worlds the Tau have colonized are relatively close to one another. The lack of psykers means that the Tau are safe from the influence of Chaos, preventing any corruption from their philosophy of the Greater Good. This also makes them deadly enemies of Chaos, as the forces of Chaos cannot corrupt the Tau and must fight them head-on.
(Please note however that this does note mean that the Tau cannot be tainted by Chaos at all. Though also note that it is very rare for such a thing to happen at all, but most certainly not impossible.)
Ethereal Caste members also have a diamond shaped bony ridge on their head. It is believed by Imperial scholars that they exert a pheromone-based control over the other castes, a theory supported by Ordo Xenos examinations of dead Tau Ethereals in the Games Workshop book Xenology.
The first contact the Imperium of Man had with the Tau occurred late in the 35th millennium, when an Adeptus Mechanicus Explorator fleet came across an inhabited star system in the Damocles Gulf. Studies of the life-supporting planet of this system, which would later come to be known as T'au, revealed an arid world with abundant xenodiversity. One species of savannah-dwellers had mastered the use of tools and fire, but the Adeptus Mechanicus teams decided that there was no worth in their continued existence, and T'au was marked for cleansing and colonisation. A colonisation fleet was dispatched, but freak warp storms destroyed the starships, and isolated the system for some time.
While the Age of Apostasy troubled the Imperium and its army, the primitive tool users that would one day become the Tau began to spread out from the plains as hunting grounds grew scarce. Each tribe adapted to their new environments with significant speed; while those that migrated to the river deltas developed their metalworking and agricultural skills, the groups that remained on the plains became skillful and aggressive hunters.
Along with the rapid adaptation came an equally rapid level of technological development. The Tau quickly came to use black powder weapons and stone fortifications. Soon, the tribes that inhabited the plains and the mountains fell into conflict with the groups dedicated to agriculture and trade. Vast inter-tribal wars were fought across the main continent, lasting for years at a time. Thousands died on each side of the conflict, while squalid conditions and lack of access to fresh food and water created a plague that killed more Tau than were dying in the wars.
By the end of the 37th millennium, the Tau were on the verge of wiping themselves out. At the same time as war and disease reached their most deadly levels, strange events began to occur. Flickering lights in the night sky and half-glimpsed figures seen in the mountains were interpreted as portents, pointing towards the end of their race. On the plateau of Fio'taun, an alliance of mountain Tau and plains Tau laid siege to the greatest fortress-city of the builder Tau. The siege had lasted five seasons, but supplies had begun to run low, disease ran rampant within the city, and the plains Tau would accept no other resolution than victory through conflict.
One night, a Tau of unusual appearance entered the attacker's camp and asked to see the army's commander. Despite being softly spoken, the sentries found themselves unable to resist the stranger, and escorted him to their leader. At the same time, another mysterious Tau presented himself to those guarding the walls of Fio'taun, asking to speak to the castellan. Again, this mysterious individual was obeyed, and within the hour he led the castellan and the other leaders of the fortress-city outside the gates. Outside, the party from the fortress were met by the first mysterious Tau, himself leading a group from the besiegers' camp. Commanding the two groups to sit, the pair of mysterious Tau, calling themselves Ethereals, began to explain how the talents of the different tribes could be harnessed. They spoke of a "Greater Good" that could be achieved through unification of the tribes, and by sunrise, the two forces had declared a truce. Over the next year, more of the Ethereals appeared, preaching the messages of peace and the Greater Good across the planet, and by the end of the year, the wars were over and the Tau began to flourish like never before. Having saved their race from extinction, the Ethereals were revered with the utmost devotion by the other Tau, who readily adapted to the new caste system established by the Ethereals.
The Tau Empire rapidly developed over the next thousand years, both scientifically and in size. Within a short period of time, the Tau developed rocket technology and quickly established colonies on the moons of T'au. Access to space allowed them to develop larger vessels, which in turn allowed the Tau to travel to nearby planets. Air caste stellar cartographers discovered that the Tau homeworld resided in a dense cluster of stars, and a supernova could wipe out their entire race, prompting further expansion. The Tau discovered the existence of the Immaterium and warp technology from an alien space vessel found on one of the moons of T'au, but as their race had no psykers, they were unable to tap into the full potential of warp travel. They were able to develop limited faster-than-light technology by modifying their gravitic propulsion system to allow a starship to 'dive' towards the Immaterium, the resulting expulsion throwing the starship a significant distance. With this new technology, the Tau began to expand into interstellar space, claiming new systems and discovering alien species. In most cases, these species were incorporated into the Tau Empire, although some, such as the Orks, resisted.
The Tau Empire came into contact with the Imperium in the middle of the 41st millennium. A Tau colony ship entered an Imperial system, and was promptly destroyed by the Imperial Navy. When the bodies from the Tau ship were analyzed, it was discovered they were the same species the Explorator fleet had encountered 6000 years before. At the same time, Rogue Traders made contact with several outlying Tau sept worlds, and began trade between these worlds and Imperial settlements on the Eastern Fringe. It was at this stage that the Tau began to realise the enormous size of the Imperium of Man. Rather than be daunted by the presence of such a huge, powerful, (and warlike) stellar neighbour, however, the Ethereals instead sent Water caste envoys to several outlying Imperial worlds where they managed to insert themselves into the Imperial commander's group of advisors. Such is the Water caste's diplomatic skill that multiple outlying Imperial worlds openly committed themselves to the Tau Empire and their quest for the Greater Good simultaneously. Alarmed by the rapid development of this xenos race and the threat of alien contamination, the Administratum declared war on the Tau, launching the Damocles Gulf Crusade. The Crusade advanced quickly, crushing any and all opposition. The Tau were subjected to horrific losses among their perimeter outposts due to the presence of Imperial Titans and Space Marines of the Iron Hands and White Scars chapters. This continued until the Imperial forces reached the Sept world of Dal'yth, where the Crusade ground to a stalemate that lasted for several months. With any hope of reinforcement cut off by pressure from the Tyranid Hive Fleet Behemoth's advance on Ultramar, the Imperial commanders accepted the Water caste's offers of peace, and were allowed to withdraw from Tau space.
In the final quarter of the 41st millennium, the Tau Empire has been assaulted by the remnants of Hive Fleet Kraken. The weakening of Imperial space by the need to defend the Cadian sector against Abaddon the Despoiler has also made open the way towards a new period of Tau colonial expansion. The Third Expansion has resulted in the establishment of several new colony worlds with minimal encroachment upon Imperial space.
Unlike other races, the Tau empire is vastly secular. Instead of centering society on gods, the Tau society is centred on the concept of "the Greater Good"; a unifying philosophy similar to utilitarianism, where individual Tau sacrifice personal gain in favour of benefiting the Tau race as a whole. It is from this philosophy that the Tau's all-purpose motto, "For the Greater Good!", is derived. The castes, although different in role and organisation, work together for the benefit of all Tau: the Earth caste provide and produce, the Water caste communicate and distribute, the Air caste connect the worlds of the Tau Empire, and the Fire caste protect. The external image of the Tau is that they are altruistic and idealistic, believing in the unification of all "for the Greater Good".
The Greater Good also encompasses other races, and any races the Tau come into contact with are invited to integrate themselves into Tau society and place themselves under the guidance of the Ethereals. The races and groups that choose to incorporate themselves earn the benefits of mutual protection, trade, and access to the technology of the Tau.
Although accepting of other races, the Tau believe that their own way is superior to any other, and harbour extreme confidence in their manifest destiny to unite the stars. They are more likely to peaceably integrate races that show similar qualities to those promoted by the Greater Good. At the same time, the Tau are imperialists. Those that will not join the Tau Empire or Embrace the Tau'va (the greater good), are forced to do so via economic, political, or military means. The Tau believe the Tau'va is for the good of all, even those who do not recognize it.
Several of the novels published by the Black Library division of Games Workshop have provided more information and detail about the Tau psyche. The novel Kill Team (Thorpe, 2001) reveals that their number of digits has led them to use a base-8 number system and that their food is similar to that of humans, although varying in taste and colour. The protagonist of the novel, Kage, notices their intricate artwork, which is so subtle that it almost goes unnoticed by humans. Their architecture is also described as consisting of works that are masterpieces in their own right, though no one building tries to outdo another in splendour, and thus they exist in perfect harmony. The Tau characters in the novel also contrast with the brutish, militant humans in their calm, patient and quiet personalities. More important yet, as the protagonists of the book discover, Tau society and ideology are far more fragile than they appear at a first glance, and Tau officials go to great lengths to keep up the illusion of stability.
The Fire Caste are the soldiers of the Tau Empire. It is their duty to protect the other castes, and as such are the Tau most often used in the tabletop game. They have relatively large muscles when compared to those of other castes. They do not train for close combat, due to the fact that they see it as barbaric (The exception being the Farsight Enclave, a broken faction separated from the Tau Empire, lead by Commander Farsight, who train and specialize in melee combat, primarily against the Orks.) When hand-to-hand combat is inevitable, it is generally entrusted to Kroot and Vespid Auxiliaries. The Tau fire caste do, however, have more agility, stamina and endurance than the other castes.
The worlds of Vior'la and Sa'cea are predominantly made up of the fire caste. The Fire Caste is divided into several septs, each originating on a separate planet, or planetary system; The primary Military Based castes are the: -D'yanoi -Sa'cea -T'au -Au'tal -Vior'la -Bork'an -Tau'n
The Earth Caste is primarily made up of farmers, labourers, and technicians; responsible for building the machines, cultivating the food, and erecting the dwellings that allow the Tau to survive. The Earth caste also includes artisans, scientists, and engineers. Members of the Earth caste are stout of build, and tend to have calloused hands and a pragmatic outlook on life.
Bork'an is well known for the number of its Earth caste.
The Water Caste is made up of merchants, diplomats, and administrators. They are responsible for maintaining effective interaction between the castes, as well as communicating with and supervising the integration of alien species into the Tau Empire or dealing with alien species. Members of the water caste range from around 5 to 6 feet which is relatively the same height as the earth caste and ethereals.
Dal'yth and Tol'ku are septs made up mostly of Water caste.
The Air Caste of the Tau traditionally functioned as messengers, but now fill the ranks of the Tau Navy (Kor'vattra), working as pilots and starship crews. The Air caste lives almost entirely off-world, and as such have developed long, slender limbs, with a skeletal and muscular structure of reduced strength. Prior to the unification of the Tau castes, the Air caste were said to possess membranous wings, allowing them to glide on warm air currents. While it is doubtful that any modern Air Caste members ever soar under their own power, they still retain a vestigial flap of skin between their arms and torso, indicating that they once had wings. They are quite tall, around 7 feet, but very thin and slender.
Tau'n and Vash'ya are the more Air-caste oriented septs.
Aun is translated as either Ethereal or Celestial, and describes the mysterious Tau subspecies that ended the inter-tribal warfare of the Tau and established the doctrine of the Greater Good. The Ethereals are the leaders of the Tau, and appear to combine the roles of priesthood and royalty in Tau society. Ethereals resemble the Fire Caste in build, but are marked by a diamond-shaped ridge of raised bone in the centre of their foreheads. Ethereals are obeyed without question by the other castes, and the Imperium suspects that this control is the result of a latent pheromone-based power.
It is not unknown or even uncommon for Ethereals to become adopted into a caste, dedicating themselves to leading that group in particular. This has often been met with approval by the senior Aun who believe it allows more in-depth leadership within the infrastructure.
The Tau homeworld and the sect T'olku are both regarded as having the wisest ethereals.
Gue'vesa ("Human Helper") is the name the Tau give to the humans who have joined their empire. After the Damocles Gulf Crusade, many Imperial Guardsmen were stranded in Tau-controlled regions of space after being abandoned by the Imperium. O'Shovah helped them by giving these humans the option of joining the Tau Empire, an offer that most accepted.
In a Ciaphas Cain novel, there are a large number of people who can be considered Gue'vesa, as they support the Tau Empire over the Imperium, even though the world in question is still under the jurisdiction of the Imperium.
In the Dark Crusade expansion to Dawn of War, upon the Tau conquering the planet Kronus, members of the Imperial guard were adopted into the Tau army. However, it was rumoured that the Tau were employing enforced sterilisation in order to control human population.
The descendants of the humans that joined the Tau Empire now maintain colonies on the edges of Tau space, and are often recruited as auxiliaries in the Tau army. The Gue'vesa are capable of producing copies of the Imperial lasgun to defend themselves, and in times of war may be armed with more advanced Tau weaponry such as pulse rifles, pulse carbines, and markerlights. These small units of humans are reviled and viewed as traitors by most members of the Imperium. As a result, in game terms, any Imperial units attacking Gue'vesa gain a bonus in close combat.
The language of the Tau is a complex, highly advanced form of communication. In sound it is deeply lyrical and soft, with many words and meanings dependent on intonation, glottal emphasis and even posture. Its multiple arrangements of polysyllabic word groups make it difficult in the extreme for human vocal cords to pronounce. Only a skilled linguist would have any hope of speaking even the most basic Tau phrases and words. This difficulty is somewhat mitigated because all Tau absorb didactic learning modules during their youth which impart the knowledge of many languages used by other species, including Imperial Gothic used by the Imperium of Man. However, while all Tau have this basic knowledge, that does not necessarily translate into skillful understanding and use of a language. Only the Water and Ethereal Castes demonstrate mastery over these other languages, which is probably born from a lifetime of practice. All other Tau castes seem to defer to Water Caste members for translation when members of the Water Caste are present, and tend to use clipped, heavily-accented speech if they are forced to communicate with other species when no Water Caste diplomat is available.
The Tau have many ways of addressing each other. To the Tau, the most important part of their name is the caste that they are born into and this forms the first portion of their identity. With the caste of a Tau established, the second portion of the name refers to their rank within society; there is no stigma attached to any rank or profession - each Tau has his or her place in society, and enjoys the respect of their peers no matter how menial the tasks that they perform. Each role is recognized as being part of the greater whole and a furtherance of the common good. With the exception of the 'Saal rank given to Tau children, there are five major levels of Tau rank, each of which has a subtly different meaning dependent on the caste to which it is suffixed. In ascending order of seniority, these ranks are as follows:
|Rank||Fire Caste(Shas)||Air Caste(Kor)||Water Caste(Por)||Earth Caste(Fio)||Ethereal Caste(Aun)|
Following the Tau's caste and rank is his planet of birth, and then his given name(s). So, for example, the famous Tau general Commander Farsight's full name is properly rendered thus: Shas'O Vior'la Shovah Kais Mont'yr (Fire Caste commander from planet Vior'la with the given names 'Farsight Skilled Blooded'), although it is frequently shortened to simply O'Shovah ("Commander Farsight"). There are also similar name constructions for certain buildings, such as Aun'bork'an'retha (an Ethereal Caste shrine/university on Bork'an) and run'al (a static observation post).
The Tau Empire, like many large governments, is divided into sub-regions. The first 'tier' of regions below the all-encompassing Empire are the Expansion Spheres. These regions represent the territories claimed during each of the three periods of expansion the Tau Empire has experienced since its establishment, and are referred to as the First through Third Sphere Colonies (although the term Sphere is interchangeable with Phase). In turn, each Expansion Sphere is divided into multiple septs, which are small regions of space focused around a fully established Tau colony-world. Each sept governs the minor Tau colonies and the worlds of other races found within its region of space.
The Tau of each sept are characterised by a number of influences, including the relative strength of the castes that inhabit the worlds of that sept, the location of the sept in proximity to the homeworld of T'au, climate of the inhabited worlds, and exposure to other races' cultures. These influences combine to affect the culture and attitudes of the Tau from that Sept. For example, the First Sphere sept of Dal'yth is characterised as a cosmopolitan society welcoming to non-Tau, based on the sept's location near several alien worlds and the large proportion of Water caste Tau in the population. In contrast, the attitude of stoicism and tenacious refusal to accept defeat that characterise the Third Sphere sept of Fi'rios is a result of the bloody battles required to take these worlds from the Orks.
The Tau continuously establish new colonies. Unlike other galactic races, including humans, if a new world is already populated they do not exterminate native race, but allow them to continue existing as part of the Tau belief in unity and peace (the Greater Good). The Tau believe in letting others believe what they want (including the worship of the Emperor of Mankind), but must be loyal to the concept of The Greater Good.
Tau ground warfare is carried out almost exclusively by the Fire caste, while the Air caste is responsible for aerial and space combat, and providing transport between systems. Fire caste military forces are known as Hunter Cadres, are similar in size and role to an Imperial Guard company, and are primarily made up of Tau from the same sept. Auxiliary forces are drawn from the alien races within the Tau Empire, and Hunter Cadres can include Kroot warriors, Vespid Stingwings, and Gue'vesa, among other forces.
Fire caste tactics are based on the concept of the "hunter". The two main schools of warfare are Mont'ka (killing blow), and Kauyon (patient hunter). Mont'ka focuses on the hunter running the prey to the ground; identifying a target of opportunity and attacking it swiftly at the right moment. A Hunter Cadre will often stand at readiness for days, waiting for the right opportunity to strike in a well coordinated and rehearsed plan of battle. Kauyon is the opposite; the hunter lures the prey into a trap through the use of bait (often a large Kroot or Vespid squad, but some septs use bonded Fire Warrior teams). The bait is exposed to the enemy, who, while moving to destroy the bait, are drawn into a position where they can be eliminated by the rest of the Cadre. The Tau prefer not to attack until all troops have been coordinated and the attack carefully planned.
The Tau prefer not to hold positions against enemy assault, and only construct bunkers to act as emergency shelters, or to use as a hidden observation post, or Run'al. If the enemy launches attacks against Tau installations and cities, the Tau will prefer to evacuate the installation, dismantle all important technology and come back later to destroy the enemy. If a city is too vital to lose it is protected primarily by the efforts of a Hunter Cadre to draw the enemy away. If this fails, the Cadre will perform attacks intended to stall the enemy while the location is evacuated, then fall back to the deserted city and use an urban warfare variant of Kauyon to defeat the enemy. In extreme circumstances, Mont'ka and Kauyon can be adapted to defend a vital location, but this type of warfare is heavily discouraged. Similarly, the Tau rarely fight in sieges or in close combat to force enemy from a territory, believing that it is preferable to simply kill the enemy at range, and then occupy the location with minimal losses. Against hardened fortifications, the Tau prefer to simply bombard the target, or, if it must be taken intact, isolate the area and cut off the defenders from any support. If a siege is forced, the Tau will conduct carefully-planned hit and run attacks designed to take out important defensive elements, such as leaders, communications, and heavy weapon emplacements, that reduce the overall strength of the defenders.
As the Tau Empire integrate more and more alien races, they use them more and more in their tactics. Often small alien squads will be used as bait in the Kauyon, though it is important to note that bait squads are not considered expendable but rather dependent on the effectiveness of their cover fire.
The Tau prefer long ranged combat over close combat. The Tau Fire Warrior's primary weapon is the Pulse Rifle, which is used alongside the Pulse Carbine. The Pulse Rifle fires energetic particles which quickly breaks down and is projected as a "pulse" of superheated plasma. The Pulse Carbine, also carried by Fire Warrior teams, sacrifices range for portability, but also carries an underslung Photon Grenade Launcher. Squads hit by the Pulse Carbine also risk being disabled by Photon Grenades. The Photon Grenades not only release a powerful burst of light but also a sonic shockwave, used to disable the target and in some cases it is rumoured to cause bowel problems in enemy troopers, much to the discomfort of those fighting the Tau.
When the Tau become engaged in close combat, they call on their mercenary allies, the Kroot. The Kroot are expert jungle fighters who appear deceptively slender, but have wiry physiques which are effectively stronger than the average human or low-level Ork boy. Many an enemy has fallen because they underestimated the Kroot. One common tactic of a Tau player is to use the Kroot as counterassault units. While the Tau are firing away at the enemy, the Kroot hide behind the lines of the Tau. When the enemy gets into charging range, the Kroot advance and charge the enemy position, buying the Tau extra time to continue firing, or withdraw to a safer position. This must be noted as a tactic used in the tabletop game of Warhammer 40,000 as the Tau in the "fiction" created see all forms of close quarters combat brutal and a waste of time and energy or frequently instruct the kroot to not engage in close combat as this will block fire lanes and is generally looked down upon by Tau. It has also been known for Kroot to spearhead city fights, harassing enemy forces, and to clear jungles and forests, as well as clearing vital positions.
On a strategic level, the Tau tactics are best described as cautious and patient. They prefer to avoid wars of attrition, and will concentrate their efforts elsewhere if an enemy seems determined to hold a specific position.
The use of Sept colours harks back to the warpaint of old and is used to distinguish teams of the same type. Displayed using stripes, these markings will be found in the same place (e.g. helmet and/or weapon) for all members of the same team.
The Tau are a relatively new race to the Warhammer 40,000 game, having been first released in October 2001. Unlike most of the races in Warhammer 40,000, which were developed from a comparable race in Warhammer Fantasy Battle, the Tau, along with the Tyranids, are the only playable races that do not possess an analogue in the Fantasy fictional universe, although most of the combat doctrines are based on the Wood Elves. The Tau ideology focuses on ranged combat, generally perceiving close-range, physical combat as crude and unnecessary. However they are definitely a force to be feared, since they have some of the strongest guns in the galaxy, including the dreaded railgun, arguably one of the best guns in the game.
The Warhammer 40,000 Design Team selected the Tau as one of three new race ideas from hundreds of possible concepts. The Kroot were one of the others, and these two were eventually combined into the one fictional organisation; the Kroot were later given their own army list in Chapter Approved.
According to Andy Chambers, the chief designer at the time, the Tau were intended "to be altruistic and idealistic, believing heartily in unification as the way forward." Graham McNeill was responsible for much of the background material produced for the Tau, developing what Andy Chambers described as "...their proud, quiet but determined character [developed] to the point where they actually became a rather likeable, if slightly naive addition to the cosmos." The Tau were updated in early 2006 with the release of a new Codex.
Since the setting of the Eye of Terror Worldwide Campaign was on the opposite side of the galaxy from the Tau Empire, and published materials had previously established that the Tau have limited faster-than-light capability, a separate 'mini-campaign' was held specifically for Tau players. Codex: Tau Empire (Hoare, 2006) was the first publication to incorporate the impact of this game event on the 40k universe. In the new background material published with the Codex, it is explained that Imperial forces were drawn away from Tau space to defend against Abaddon's Thirteenth Black Crusade. This left a power vacuum that prompted the Tau to initiate their Third Sphere Expansion.
In the campaign, registered games involving the Tau contributed to the expansion or contraction of Tau-controlled space. Over eight weeks of gaming, the Tau Empire grew by nearly a third due to victories.
The Tau Empire was 6th overall (tied with the Orks) in the conclusion of the 2006 Medusa V Campaign.
The Tau expedition's goal, to gather information about the warp, was largely successful. The Fourth Expansion of the Tau Empire was thus delayed in order to further consolidate the recent Third Expansion. As well as attaining the warp data, many human refugees joined the Tau Empire, new technologies were acquired, and Tau warriors gained valuable combat experience, though with great losses, personified with the loss of Commander Shadowsun's sibling, Shas’el Ty’res.
Tau miniatures were designed to display the high-tech science fiction and robotic concepts that had resulted in the choosing of the Tau as the new army-race. The reflection of the Tau's high-technology status was reflected by the lack of cabling and links modeled onto the weapons; instead it was decided that these components were internally integrated. The Tau Infantry models, according to sculptor Jes Goodwin, were designed to have subtle influences taken from Chinese foot soldiers, while the Battlesuits and vehicles drew from anime style exo-suits. The Tau vehicles are 'skimmers'; however, the design brief specified that the Tau Tanks have an impression of being heavier and more solid than the Eldar Grav-tanks.