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"We are five castes, one people. We stand united, dedicated wholly to the Greater Good. As we progress, we will encounter further barriers. We will overcome them. Our future is now, believe in our destiny."

Ethereal Supreme Aun'Va

The T'au Empire (pronounced "TOW" as in "WOW"), also spelled Tau Empire in older Imperial records, is a rapidly expanding, multispecies xenos stellar empire situated within the Imperium of Man's Ultima Segmentum, near the Eastern Fringes of the Milky Way Galaxy. It lies within the reach of the Astronomican.

The T'au Empire was founded by the T'au caste called the Ethereals, who lead the T'au Empire in the name of and in accordance with the utilitarian philosophy they have named the "Greater Good" (Tau'va in the T'au Lexicon). A large and growing number of other intelligent, alien races have allied themselves with the T'au within the empire.

The empire has suffered many raids from the Orks, and also seems to lie in the path of several Tyranid splinter fleets of Hive Fleet Kraken.

The T'au (Imperial binomial classification: Tau tau), also spelled "Tau" in older Imperial records, are a young, humanoid and technologically-advanced intelligent species native to the Eastern Fringes of the Milky Way Galaxy. They are fighting to expand their small, but rapidly growing, interstellar empire and extend a philosophical concept they call the "Greater Good" to all the intelligent species of the galaxy.

The T'au claim to be a peaceful species when possible, asking if others will join their cause voluntarily instead of fighting against them. However, if their peaceful overtures are refused, the T'au may well decide to conquer a planet and add it to their growing stellar empire for the Greater Good, searing the flesh from the bones of anyone who stands against their benign intentions.

T'au society is divided into a number of castes, each responsible for managing a specific aspect of their civilisation. The T'au's central motivating ideal is that everyone in their empire, regardless of their species or culture of origin, will work for the collective betterment of everyone else, an almost mystical philosophy that is embodied in the Greater Good.

The T'au are the dominant species of the T'au Empire, an interstellar polity which is also composed of several other different intelligent species, including the Kroot of Pech, the insectoid Vespids of the world of Vespid, the nomadic psykers of the Nicassar and many others.

However, there are now several Human septs in the empire derived from conquered Imperial Humans or Humans who voluntarily joined the T'au Empire because they were impressed by the concept of the Greater Good. These people are known as Gue'vesa in the T'au Lexicon and they are considered amongst the most vile of Traitors and Heretics within the Imperium.

The T'au are a relatively young species (it has been only 6,000 Terran years since Imperial Inquisitors first noted that the T'au had only just mastered fire and the wheel), and they have evolved rapidly over the past few standard millennia. Unlike other intelligent, starfaring species, the T'au have made remarkable leaps in technology and now represent a real threat to Imperial domination in their region of the galaxy.


The Mont'au and the Coming of the Ethereals


An astrographical representation of the T'au Empire

The exact date of the founding of the T'au Empire in the Imperial Calendar is unclear. However the way in which the T'au were united as a species is a well-known tale. What is known is that only 6,000 standard years ago, in the 35th Millennium, an Adeptus Mechanicus Explorator fleet discovered the T'au homeworld of T'au and determined that its population of intelligent xenos were a primitive people at the Stone Age level of development, having only just mastered fire. Since then, the T'au have developed very rapidly into a space-faring species.


A more detailed astrographical map of the T'au Empire following the end of the Third Sphere Expansion.

Earlier in their history, during a period known as the Mont'au, the T'au were a culture built upon warring tribes. During this time, the T'au's legends tell of the first appearance of the Ethereals at the city of Fio'taun. The fortress city of Fio'taun was under assault by the T'au warriors from the plains. Though negotiation had been attempted, the fierce plains warriors would settle for nothing less than the annihilation of the city of Fio'taun.

For five long T'au years the inhabitants held off the savage assaults with their thick walls and plentiful cannons. However, disease and starvation began to take their toll. As the tide of the siege turned, two mysterious T'au appeared. One made his way into the camp of the plains T'au, exuding a quiet authority that no T'au was able to resist. Soon, the leader of the plains warriors was persuaded to parley with the settled T'au of Fio'taun. Similarly, the other mysterious T'au made his way deep into the fortress. Within a few short hours, the gates stood wide open, and T'au of both sides stood ready to talk.


A map of the T'au Empire's position in the galaxy after 999.M41 and the birth of the Great Rift in the Era Indomitus.

The Ethereals spoke of the importance of peace and understanding between all T'au. They described a Greater Good that each T'au must strive towards. The besiegers and the besieged quickly agreed with the Ethereals and a truce was reached. Across the world of T'au, Ethereals emerged, each with the same quiet authority and message of harmony and cooperation. With the T'au united, they were able to rapidly develop their civilisation's technology, ultimately attaining spacefaring capabilities.


Map of the T'au Empire at the time of the Fifth Sphere Expansion after the opening of the Great Rift in the Era Indomitus.

The T'au Empire soon expanded its borders through a series of so-called "Sphere Expansions." The T'au Empire has gone through five main phases of expansion as of the Era Indomitus in the 41st Millennium. These phases are marked by T'au military campaigns during which new worlds and star systems are colonised, conquered, or sometimes peacefully persuaded to accept the Greater Good through diplomacy and a manifest demonstration of the benefits provided by advanced T'au technology.

Apart from the star systems directly colonised and exploited by the T'au, which are known as "septs," the T'au Empire also includes the worlds and star systems belonging to the species of the Kroot, Vespid, and the Nicassar. It is currently unknown if the Leagues of Votann Prospect called the Demiurg by the T'au are full members of the empire, allies, or mere trading partners. The T'au Empire is composed of over twenty fully-developed septs and around one hundred settled worlds, but the exact number and most of their names are unknown to the Imperium.


A T'au Fire Warrior

A known splinter faction among the T'au are the Farsight Enclaves, founded beyond the Damocles Gulf by the T'au Commander Farsight against the orders of the Ethereals. More recently, some worlds and star systems of the Imperium have been conquered by the forces of the T'au, while a handful have seceded from the Imperium outright and pledged their allegiance to the T'au Empire and the Greater Good.

Damocles Gulf Crusade

The Damocles Gulf Crusade, also called the Damocles Crusade, was the first military conflict fought between the Imperium of Man and the rapidly expanding T'au Empire in the Lithesh Sector of the Ultima Segmentum near the galaxy's Eastern Fringes during the 41st Millennium. The conflict essentially ended in a stalemate, as the Imperium was forced to conclude its military offensive early to deal with the encroaching Tyranid threat while the T'au sought to begin diplomatic negotiations with the Imperium to show Humanity the benefits to be had by accepting the Greater Good.

Before the crusade, members of the T'au Water Caste had established trade agreements with Imperial worlds on the frontier of the T'au Empire, near the Damocles Gulf region of the Ultima Segmentum in the galactic east, and exchanges of goods and technology were common. Alarmed by the threat of alien contamination, the Administratum readied a suitable response. Almost a Terran century later, the Damocles Crusade smashed into T'au space, destroying several outlying settlements and pushing deep into the T'au Empire.

When the Imperial fleet reached the T'au Sept World of Dal'yth Prime, however, the crusade ground to a bloody stalemate as the formidable numbers and high technology of the T'au and their Kroot allies thwarted every attempt to capture the world or its star system. Many solar months of terrible fighting ensued with nothing gained on either side.

By late 742.M41 the crusade's commanders eventually agreed to requests from the T'au Water Caste for peace talks. The negotiations were successful and the Imperial fleet withdrew from T'au space unmolested, their reason partly being due to the impending approach of the Tyranid Hive Fleet Behemoth.

Hive Fleet Gorgon

War Without End by MajesticChicken

The T'au repelling the Tyranid swarms of Hive Fleet Gorgon

The T'au Empire was invaded by the Tyranid Hive Fleet Gorgon, a splinter fleet of the much larger Hive Fleet Behemoth, in 899.M41. The Tyranids of Hive Fleet Gorgon were exceptional in their ability to quickly adapt on a biological level to new circumstances of battle, such as evolving immunities to the T'au's energy-based weaponry.

This rapid pace of defensive adaptation may have been unique to the Tyranid breeds of Hive Fleet Gorgon, or it may have been a response to conflict with the T'au, who are also a highly adaptable species; albeit on a technological rather than biological level.

The combined forces of the T'au and the Imperium's Astra Militarum destroyed Hive Fleet Gorgon in 903.M41, though only after both Humanity and the T'au lost several colony worlds to the rapacious Tyranids.

Alliance on Malbede

At some point, the T'au sent an expeditionary force to the Imperial planet Malbede where they came into conflict with the Ultramarines Space Marine Chapter in 936.M41. However, the planet proved to be a cursed Tomb World when the fighting of the T'au and the Ultramarines awakened the sleeping Necrons from their tomb beneath the surface. In an effort to combat this terrible threat to both species, the T'au and the Ultramarines combined their forces to defeat the Necrons. Once the conflict was over, the T'au were allowed to evacuate their forces by the Ultramarines Chapter Master Marneus Calgar who proceeded to destroy Malbrede through the use of an Exterminatus order.

War for Kvarium Alpha

Tau empire

The T'au Empire's Fire Caste at war; these battlesuits are among the most potent of all T'au forces.

In 966.M41, the T'au fought against the Astartes of the Space Wolves Chapter during the War for Kvarium Alpha. On that Ocean World, the Space Wolves' Drop Pods landed deep in the oceans where their occupants, their power armour altered by Space Wolf Techmarines to operate in undersea environments, made a move to engage their enemy.

On the surface, the battle was fought between the two sides with an equally deadly conflict erupting in the depths of the sea between the Space Wolves and T'au Battlesuits. Thunderhawk gunships armed with torpedoes, prop-bombs and missiles were used to great effect against the T'au's Hammerhead tanks and Manta gunships. Ultimately, the Space Wolves proved to be the victor in the conflict, though hundreds of T'au and Space Wolf corpses floated to the surface of Kvarium Alpha's world sea. With their mission complete, the Space Wolves made the long trek back to land across the sea bed.

Taros Campaign

The Taros Campaign was an Imperial military campaign fought by the 4621st Imperial Guard Army and elements of the Adeptus Astartes to reclaim the Imperial desert Mining World of Taros from the T'au Empire and its Kroot and Human (Gue'vesa) allies of the Taros Planetary Defence Force in 998.M41. The campaign was ultimately unsuccessful for the Imperial forces, who took heavy casualties and losses whilst Taros remained in the possession of the T'au, who renamed it T'ros.

T'au Anatomy and Physiology


A T'au Fire Warrior in full military kit.

The T'au's physiology is closely tied to their society, with the T'au of each caste effectively being a subspecies of the larger T'au race. This was initially a result of adaptation and evolution to suit the different environments each group of the proto-T'au species found themselves in on their homeworld of T'au, although interbreeding between the castes was later forbidden by the Ethereals.

The T'au are humanoid in shape, although they have hoofed feet and four-digit hands (three fingers and one thumb). Their skin is grey-blue (although this can vary in pigmentation between T'au septs and colony worlds), rough in texture, leathery, and exudes almost no moisture. Their faces are flat, wide around the eyes, with an "I"-shaped slit running from the center of the forehead to where a Human's nose would be.

T'au vision is considered slightly superior to that of 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 providing slower vision focusing reflexes than Humans, particularly in low light conditions. The olfactory organs of a T'au are inside the mouth.

Physical strength and size varies between the T'au castes with the Fire Caste being the strongest of their kind, roughly the size and slightly weaker than an average baseline Human because the T'au homeworld has gravity slightly weaker than that of Terra.

Only two female T'au have ever been illustrated. The first, Commander Shadowsun, appeared to have a more Human face than male T'au; 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 T'au. The second known T'au female, the subject of an Imperial dissection by the magi of the Adeptus Mechanicus, had the facial characteristics of a male T'au.

Tau Battles

The T'au Fire Caste in battle.

The T'au do not possess psykers 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 psychic powers. This is because the T'au have virtually no psychic presence in the Warp. To a Daemon or any psykers possessed of the witchsight, they appear as a shifting will-o-the-wisp rather than the burning fire that represents a Human's soul. As such, T'au can never possess or develop psychic powers.

The T'au are largely unaware of the perils of the Immaterium and for this reason have conducted research into the nature of 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."

Ethereal Caste members also have a diamond-shaped bony ridge on their head. It is believed by Imperial scholars that through this organ the Ethereals exert a pheromone-based or latent psychic control over the other T'au castes to keep them focused on the Greater Good, but this is mere speculation, and no evidence of this has yet been found.

Due to their notable absence of psychic ability, the T'au have no equivalent to the Navigators of the Imperium, forcing them to travel at sublight relativistic speeds. Their interstellar vessels therefore take much longer than Imperial vessels to traverse the vast distances between the stars, which is one reason their empire has expanded relatively slowly over the centuries.

Tau Fire Warriors

T'au Fire Warriors in full armour.

T'au warriors receive only limited training in the arts of close combat, usually depending on Kroot mercenaries to fight in the horrible melees so common in 41st Millennium battles. However, due to the T'au's superior range of vision in the electromagnetic spectrum and a predilection for patience, the T'au have proven themselves to be extremely efficient sharpshooters with the ranged plasma weapons and railguns they primarily rely upon.

The T'au tend to look upon other intelligent species as backwards or misguided. Before the commencement of hostilities they almost always try to reason with their opponents and establish some kind of agreement that will make the use of military force unnecessary. Noted exceptions to this policy are T'au battles with the Orks, Tyranids and the forces of Chaos, with whom the T'au have little to no diplomatic relations. This is due to the fact that the T'au see no way to reason with them, and do not want them in their empire.

Greater Good

The Greater Good, or "Tau'va," is the central philosophy that unites all T'au. It teaches that every self-aware being is equal and plays an important part in T'au society. It tells its adherents to put away petty squabbles and unnecessary things to unite for the greater good of the rest of their species and of all other intelligent species in the galaxy.

The T'au have no desire to destroy another intelligent species' religion or culture -- though it may not mean that the T'au respect their right to live as they please. However, while many embrace this ideology, and even some Imperial worlds have willingly joined the T'au Empire, other species fiercely resist adhering to the Greater Good to pursue their own freedoms, much to the dismay of the T'au, who see these desires as selfish and unenlightened.

T'au Caste System


The Ethereal Supreme Aun'Va, the leader of the Ethereal Caste and the Ethereal High Council and thus the Aun'o of the T'au Empire.


The T'au employ a caste-based social system that places the good of the many over the good of the few or the individual. In T'au culture, every person is viewed as an essential part of the whole society, though no individual is ever considered more important than the needs of the rest of society.

Social standing is judged primarily by a being's standing within a caste of the T'au, with the suffix 'la designating the lowest rank in the caste (shas'la: Fire Warrior, fio'la: Earth Worker, por'la: Water Bureaucrat) and the suffix 'o designating the highest (shas'o: Fire Commander, fio'o: Earth Planner, por'o: Water Ambassador). The five castes of the T'au are as follows:

  • Fire Caste (Shas) -- The Fire Caste composes the bulk of the ground military of the T'au Empire, and as such are the T'au most often encountered by the Imperium. They average as tall as or slightly shorter than an average Human, and are generally muscular. This comes from the Fire Caste's origin on the plains of T'au, the T'au homeworld, where they survived as hunters and warriors. T'au from the world of Vior'la tend to have slightly greater muscle mass than is common among their species because of the increased gravity of Vior'la.
  • Earth Caste (Fio) -- The Earth Caste is composed not only of the T'au's labourers and technicians, but also artisans, scientists and engineers. They are usually credited with the significant leaps in technology that the T'au Empire has enjoyed. The members of the Earth Caste form the foundations upon which the T'au Empire is built. The inhabitants of this caste are generally short and stout of build.
  • Water Caste (Por) -- The Water Caste is primarily composed of T'au merchants and diplomats. They are tasked with seeking and maintaining diplomatic relations with the other member species of the T'au Empire, as well as maintaining the ease of communication and cooperation between the other castes. The Water Caste are generally taller and slimmer than other T'au, and favor diplomatic training and social grace over confrontation or combat. They are more capable in communicating in the languages of other intelligent species than most other T'au. From the time when the T'au discovered the existence of the Imperium, there are several accounts where Water Caste ambassadors were dispatched to Imperial worlds, and those worlds accepted the Greater Good without a fight to become new T'au septs.
  • Air Caste (Kor) -- The Air Caste of the T'au function not only as messengers, but also as the bulk of the T'au Protection Fleet and the T'au Merchant Fleet. The T'au of the Air Caste are even taller and more slender than the Water Caste, with long, skinny appendages and hollow bones. These traits are attributed to their lives lived mostly in low to zero-gravity voidships and void stations. This is exacerbated by Air Caste reluctance, if not outright refusal, to land on planets, as their skeletons have atrophied to the point where injury and broken bones are commonplace when they spend time in a gravity well. In the past, during the time of the Mont'au before the unification of the T'au tribes, the Air Caste had membranes stretching between their limbs, which allowed them to glide on air currents. T'au Air Caste pilots are recognised as generally superior to Human pilots due to their better fighter craft, though they lack a normal Imperial pilot's level of combat experience.
  • Ethereal Caste (Aun) -- The Ethereals are the political and religious leaders of the T'au. They resemble the Fire and Water Castes physically, but are marked by a diamond-shaped ridge of raised bone in the centre of their foreheads. Their origins are unknown, and most T'au will never refuse a request made by an Ethereal. They are sometimes also found on the battlefield, but whether as leaders or observers remains to be seen. The leader of the Ethereal Caste is a T'au named Aun'Va, the Ethereal Supreme and Master of the Undying Spirit who chaired the Ethereal High Council and served as the head of state or Aun'o of the T'au Empire.

Ethereal Control

One of the theories surrounding the T'au concerns the Ethereals' method of political control over other T'au, and how the Ethereals initially managed to unite a fractured, nomadic species comprised of multiple and mutually antagonistic sub-species constantly at war into a single people and military force.

The proposed causes of this range from the psychic to the biological, including that the Ethereals' diamond-shaped forehead ridge, an organ unique to that caste's anatomy, produces a set of pheromones that make T'au, and to a lesser extent other intelligent species, open to suggestion.

This concept was introduced after fans complained that the initial T'au codex described the T'au in too much of a positive light, and that they were too "good" for the grim, dark Warhammer 40,000 universe. This also led to the introduction of the Vespid Communion Helms, which have a much clearer Orwellian feel that the Vespid are being directly manipulated by the T'au thanks to the helmets that are supposedly for "communication purposes."

T'au Caste Ranks

The rank of a person in T'au society is second only to the caste they are born into in determining their position in T'au culture. The ranks are as follows, with the prefix denoting the individual's caste preceding the suffix that determines rank within the caste. The translation of each rank into a Low Gothic term that approximates it follows.

Rank Fire Caste (Shas) Air Caste (Kor) Water Caste (Por) Earth Caste (Fio) Ethereal Caste (Aun)


Cadet (Apprentice for non-Fire Caste)


Warrior Messenger Bureaucrat Worker Prince


Veteran Carrier Envoy Senior Prelate


Hero Pilot Magister Overseer King


Knight (Sub-Commander) Captain Diplomat Engineer Holy


Commander Admiral Ambassador Planner Ethereal Supreme

  • 'saal - A cadet. This rank is typically given to T'au as soon as they enter service in the Fire Caste or any of the other castes, where the term might also translate more appropriately as "apprentice."
  • 'la - The first and lowest true rank of T'au society. A Fire Caste shas'la would be a standard Fire Warrior, while an Earth Caste fio'la would be a manual laborer, and an Air Caste kor'la a crewman on a T'au voidship.
  • 'vre - The third T'au rank. A Fire Caste shas'vre is a battlesuit team leader or bodyguard, an Earth Caste fio'vre would be the foreman of a T'au factory, and an Air Caste kor'vre a fighter pilot.
  • 'el - The fourth and second highest T'au rank, acknowledged as one of high esteem. Fire Caste shas'el are sub-commanders, essentially junior T'au Commanders, Air Caste kor'el command T'au voidcraft as their captains, and an Earth Caste fio'el would be a senior engineer.
  • 'o - The highest T'au rank in any caste. An Air Caste kor'o would be the title of a fleet admiral, while a Fire Caste shas'o would be a top Fire Caste field commander, essentially a T'au general and a fearsome warrior in their own right usually placed in command of one or more cadres or even a contingent. An aun'o is the highest rank of Ethereal as Ethereal Supreme and head of the Ethereal High Council, revered by all T'au as the leader of their people.

Before the unification of the T'au Empire under the rule of the Ethereals, the four main castes (Fire, Earth, Water, and Air) were constantly vying for power with each other in the form of different tribes and sub-species. The sudden appearance of the mystical T'au of the Ethereal Caste led to the unification of the T'au under the utilitarian philosophy of the "Greater Good."

The T'au are the most open and tolerant of the intelligent, starfaring species in the Warhammer 40,000 universe. They are the only faction that prefers to settle their differences peacefully, when possible. They are appreciative of Humans, Aeldari, and the other intelligent species, but hold their own values to be superior to those of others because they view themselves as seeking to build an unselfish and enlightened society.

Their tolerance also extends to themselves, as the T'au recognise even lowly Earth Caste fio'la workers as being as important to the operation and well-being of the T'au Empire as the Fire Caste's shas'vre battlesuit leaders or even the Ethereal Supreme aun'o who leads the empire.

T'au Names

T'au names are tied closely with their lives within the empire. A T'au's full name always starts with their caste and their rank within that caste, followed by the sept (planetary system) of their birth, followed by their personal name, which is often determined/extended by their notable actions or achievements in life.

Thus, the name of the T'au Shas'O Vior'la Shovah Kaius Mont'yr (see below) would be broken down as follows:

  • Shas -- The individual is a member of the Fire Caste...
  • 'O -- ...who is a high-ranking commander and hero...
  • Vior'la -- ...who comes from the sept of Vior'la...
  • ...and has a personal name translated as being far-sighted (Shovah), skilled (Kaius, possible variation of Kais), and having seen many battles (Mont'yr, meaning "blooded").

T'au Warfare

General Principles

Tau's Military

T'au military forces besiege an Imperial hive city.

T'au ground warfare is carried out almost exclusively by the Fire Caste, whilst the Air Caste is responsible for aerial and space combat, and providing transport between star systems for the Fire Caste. Fire Caste military forces are known as cadres, and are similar in size and battlefield role to an Astra Militarum company.

In space, T'au fleets are manned by the Air Caste which maintains both the military starships of the T'au Protection Fleet, called the Kor'vattra in the T'au Lexicon, as well as the state-owned, armed merchant vessels of the T'au Merchant Fleet.


A selection of T'au Wargear recovered from the battlefield.

The T'au Protection Fleet can include both T'au starships as well as those of the xenos auxillaries who are a part of the T'au Empire and accept the Greater Good, such as Kroot War Spheres and the powerful vessels of the Leagues of Votann Prospect identified as the Demiurg.

Hunter Cadres are primarily made up of T'au from the same planetary sept. Auxiliary forces are drawn from the alien member species within the T'au Empire, and Hunter Cadres can include Kroot warriors, Vespid Stingwings, and Human Gue'vesa amongst other intelligent xenos species.

The T'au prefer long-ranged combat over close melee, disdaining the latter and viewing it as primitive and barbaric. A T'au Fire Warrior's primary weapon is the Pulse Rifle, which can be switched for a Pulse Carbine. A Pulse Rifle fires energetic particles which quickly break down and are projected as a "pulse" of superheated plasma. Pulse Carbines, also carried by Fire Warrior teams, sacrifice range for portability, but incorporates an underslung Photon Grenade Launcher.

Photon Grenades are powerful defensive weapons that not only release a powerful burst of light, but also a sonic shockwave that can temporarily stun the target. As the T'au Empire integrates more and more alien races, they use whatever unique abilities they possess in supplementing T'au tactics.

Often small alien squads will be used as bait to draw enemy fire, though it is important to note that bait squads are not considered expendable but rather dependent on the effectiveness of their cover fire.

If T'au forces ever do become engaged in close melee combat, they can call on their cannibalistic allies, the Kroot. The Kroot are expert jungle fighters who appear deceptively slender.

Unit Organisation


Sample Hunter Cadre order of battle

A cadre, or kau'ui in the T'au Lexicon, is the basic organisational unit of the Fire Caste, the ground military forces of the T'au Empire. Cadres are in turn made up of a variable number of units similar in size to squads known among the T'au as a "team."

There are many types of T'au cadre, but by far the most common one is the versatile Hunter Cadre. It is a combined arms group, fielding Fire Warrior infantry, auxiliary infantry, battlesuits and anti-gravitic gunships together under the leadership of a T'au Commander. Most cadres are standing formations, although their exact structure includes some variation depending upon the strategic or tactical needs of their commander.

There are many alternative kinds of cadre within the Fire Caste, with several more specialist formations optimised for specific battlefield roles. The Retaliation Cadre, for example, groups teams of battlesuits, particularly stealthsuits, into a single force ideal for rapid insertion drops and counter-assault. Meanwhile, the Infiltration Cadre is utilised for reconnaissance in force, its Pathfinders, Sniper Drone Teams and Piranhas engaging the foe with guerrilla tactics while calling down strikes on key strategic targets.

A "contingent", or tio've, is a grouping of cadres similar in size to an Astra Militarum regiment, normally three to six in number and assembled to prosecute a specific battle or achieve a particular objective. Such large forces will always include at least one Ethereal, who is there to observe proceedings and offer guidance to the commander. The Ethereal's role is vital, for contingents represent the marshalled military might of the T'au Empire and must be wielded with care -- only the vast, star system-conquering units known as "coalitions" or shan'al are larger and more powerful.

Fire Caste

A Fire Warrior Cadre Fireblade commanding a Hunter Cadre.

Fire Caste armed forces are deployed to protect T'au holdings or to destroy those that oppose the T'au Empire's enlightenment. In order to achieve success with their rapid strikes and ambushing firefights, T'au forces must be flexible, and ready to work together. It is a Fire Caste mantra that every unit must operate in conjunction to fulfil the dictates of the Greater Good.

Teams (La'rua)

The smallest standard unit in the T'au military's Fire Caste is known as a "team," equivalent to an Astra Militarum squad. The most commonly deployed is the Fire Warrior Team, the backbone of most T'au armies and the basic infantry unit. Each team of Fire Warriors consists of between six and twelve soldiers. All members of a team come from the same sept, and most likely have gone through Fire Caste academy together. All teams have a team leader, although they can only earn the higher rank of shas'ui after extensive battlefield experience.

Teams that serve together in the field often bond themselves through rituals, of which the most famous is the Ta'lissera, which roughly translates to a type of communion or binding oath. Those who have sworn such an oath may address each other by their individual names and have vowed to support one another unto death.

It is not uncommon for teams to progress together as well -- veteran Fire Warrior Teams may even earn promotion to shas'ui together. Each might serve for a time as a squad leader for a different Fire Warrior Team before the survivors are reunited as a Crisis Team.

Cadres (Kau'ui)

A "cadre" is a collection of teams joined under a single T'au Commander and is equivalent in size to an Astra Militarum company. There are many types of cadre, but by far the most common one is the versatile Hunter Cadre. It is a combined arms group, fielding infantry, battlesuits and gunships together. A cadre is comparable in size and power, if not in composition, to what the Astra Militarum might call a company.

Hunter Cadres are a standing formation, although their exact structure is variable, subject to change due to the tactical situation on the ground, the quarry they are hunting, the available reinforcements or a commander's favoured mode of attack. The core of most Hunter Cadres is its Fire Warriors and other auxiliary infantry such as Kroot Carnivores or Vespid Stingwings, but these can be supported in a number of ways. Pathfinders scout ahead and mark prospective targets, elite battlesuits provide hard-hitting strike teams, Sniper Drone Teams pick off the foe's greatest threats and Hammerhead gunships use their deadly armaments to blast enemy armour or break up massed infantry attacks.

The doctrine of T'au battle tactics is all about the efficient coordination of different groups -- from the infantry to the battlesuits, the gunships to the aircraft, all must work as one to defeat the foe. A Hunter Cadre is fully integrated at the tactical level, so that all of its teams are considered to be part of the same fighting unit.

There are a number of different cadres in addition to the hunter variety, although they tend to be smaller in size and more optimised for individual roles. There are Rapid Insertion Forces made exclusively of fast striking battlesuit teams, Infiltration Cadres of Pathfinders and Stealth Teams and Auxiliary Reserve Cadres, battle groups made entirely of allied alien warriors like the Kroot, Vespids and Gue'vesa.

A particularly formidable group is the Armoured Interdiction Cadre, a force composed entirely of Hammerhead and Sky Ray gunships. Its heavy firepower is used to counter enemy tanks and is capable of toppling even the mightiest targets. During the Hive Fleet Gorgon invasion, Armoured Interdiction Cadres blunted the Tyranid Bio-Titan spearhead -- pitting "shoals" or squadrons of Hammerheads against towering Hierophants flanked by the tank-sized Hierodules.

Contingent (Tio've)

A "contingent" is a grouping of several cadres, normally three to six in number, equivalent to an Astra Militarum regiment. The most senior T'au Commander is designated as Contingent Commander, and their own cadre is nominated as a headquarters guard. An Ethereal might be present in such a force at cadre level, but there is always at least one present when a contingent is formed.

Ethereals often stay at the headquarters position, as it is a hub for incoming reports and their counsel can best be received there. Should an Ethereal wish a closer observation of a situation, they will attach to or even assume leadership over a given cadre.

Unlike a cadre, a contingent is not a permanent formation, though efforts are made to preserve contingents that have served efficiently together through prolonged campaigns. Once objectives are achieved -- such as a breakthrough of enemy lines or the elimination of a foe -- the contingent is dissolved or reformed into another arrangement.

Commune (Kavaal)

Sometimes also translated into Low Gothic as a "battle," a "commune" is a temporary grouping of contingents and the highest level of Fire Caste military organisation thus far committed in the field by the T'au Empire.

Communes are often formed by contingents from different septs, and although rarely seen before the Damocles Gulf Crusade, they are now more regularly formed, most famously during the solar-decade-long campaign against the Orks known as the Great War of Confederation.

Only the combined forces of many septs could have hoped to stop the gargantuan Ork WAAAGH! that threatened the empire.

Commands (Uash'o) and Coalitions (Shan'al)

A "command" is the term used for all the forces of a single caste in a given location, usually on a planet or in a star system. For instance, all the Fire Caste members on the world of Nimbosa were part of Fire Caste Command Nimbosa, while all Air Caste formations were part of the Air Caste Command Nimbosa.

The largest unit of T'au military organisation is created when the four commands that together comprise the members of all four T'au castes present in a given location are drawn together into a strategic organisation referred to as a "coalition," effectively the size of an Astra Militarum army or army group. A coalition is presided over by a specially assigned Ethereal council.

Types of Cadres

Below is an example of a T'au Fire Caste Hunter Contigent which is a combined arms unit making use of many different types of cadres.

Hunter Contingent

Fire Caste Icon

The Hunter Contingent is designed to be the most versatile template by which large Fire Caste forces can be assembled. Such a formation exhibits the strategic balance to face any threat.

Command Hunter Cadre

Large forces, such as units of contingent size or larger, will always include at least one Ethereal who acts as the overall, strategic force commander.

A Hunter Cadre is a combined arms group, fielding infantry, battlesuits and gunships together under a T'au Commander.

Cadre Types

A contingent -- or tio've -- is a grouping of cadres, normally three to six in number and assembled to prosecute a specific battle or achieve a particular objective. Such large forces will always include at least one Ethereal, who is there to observe proceedings and offer guidance to the T'au Commander.

Optimised Stealth Cadre Fire Support Cadre Allied Auxiliaries
XV25 Stealthsuit Teams
XV95 Ghostkeel Battlesuit
Fire Support Cadres are used to assault vulnerable points in enemy lines.
2 XV88 Broadside Battlesuits
1 XV104 Riptide Battlesuit
Kroot mercenaries, Vespid Stingwings, Gue'vesa units 
Infiltration Cadre Heavy Retribution Cadre Air Caste Support Wing

Utilised for reconnaissance in force, this Cadre's Pathfinders, Sniper Drone Teams and Piranha engage the foe with guerrilla tactics while calling down strikes on key strategic targets.

Pathfinder Teams
Stealthsuit Teams
Supported by Sniper Drones
Piranhas (Reconnaissance)

Used to annihilate the most stalwart of enemies.

2 KV128 Stormsurges
XV95 Ghostkeel Battlesuit
Other Cadre Types

Ranged Support Cadre
Piranha Firestream Wing
Skysweep Missile Defence
Drone Net VX1-0
Riptide Wing

T'au Combat Doctrine

Tau with kroot

T'au and their Kroot allies, fighting for the Greater Good.

T'au warfare is carried out almost exclusively by the Fire Caste, with support from the Air Caste in the form of transport and air support. The T'au draw their tactics from their ancient methods of hunting across the plains of T'au. Each force is usually drawn from the same sept, and is called a "Hunter Cadre."

The T'au prefer to carefully plan their assaults, and tend to fight only after coordinating their troops and weapons for the mission at hand. The T'au prefer to fight offensively, concerned more with the quick destruction of the enemy force than the taking and holding of ground. If a T'au base is attacked, the T'au will usually evacuate, dismantle all important technology, and return at a later time to retake it.

The two primary T'au tactics are the Mont'Ka ("Killing Blow") and Kauyon ("Patient Hunter"). The Mont'ka is a carefully planned attack designed to wipe out critical enemy defences or units in a single well-placed strike. Once the strongest points of enemy resistance are crushed, the remainder of the force can generally be finished off easily. The Kauyon is essentially an ambush, where the enemy is drawn by use of a "lure" into a carefully prepared killing zone. The Mont'Ka is generally known to utilise more mobile support and vehicles, whilst Kauyon relies more on advanced infantry tactics and quick attacks.

As T'au forces generally prefer ranged combat they always use non-T'au alien auxiliaries like the Kroot for melee support. One commonly used tactic is when a squad of Fire Warriors stands in front of the task force, making use of the superior range of their weapons to soften up enemy formations. A squad of Kroot Carnivores waits behind the Fire Warriors. When enemy units charge to engage the T'au in melee, the Carnivores leap in front of the Fire Warriors to give them time to retreat to a safe firing position.

Member Species

Each intelligent alien species within the T'au Empire has a unique and different culture which contributes to the Greater Good in its own way.

However, all of the T'au Empire's member species hold to their common belief in the Greater Good that binds them all together despite their myriad cultural and physical differences.


Tau FireWarrior2

A T'au Fire Warrior

T'au society is centred around the philosophical concept of the Greater Good, where individual T'au sacrifice their personal gain in favour of benefiting the T'au Empire as a whole. It is from this philosophy that the T'au's all-purpose motto, "For the Greater Good!", is derived.

The T'au castes, although different in role and organisation, work together for the benefit of all T'au: the Earth Caste provide and produce, the Water Caste communicate and distribute, the Air Caste connect the worlds of the T'au Empire, and the Fire Caste protects and defends all the others.

The external image the T'au project towards other species is that they are enlightened, altruistic and idealistic, believing in the unification of all "for the Greater Good."



A Kroot warrior

Kroot society is divided into tribes, known as "Kindreds." Each Kindred is an extended family group of Kroot and is led by a Shaper, one Kroot with an intuitive understanding of the DNA absorption and adaptation process all Kroot possess, and responsible for guiding the evolution of their Kindred.

The Shaper, upon identifying a beneficial genetic trait, will instruct his Kindred to hunt and consume that animal, and then control the breeding of the Kindred to ensure that the offspring are born with the selected trait. Often, Kindreds will band together and their respective Shapers will form a council, of which the most influential Kindred's Shaper will be made leader of the entire group. On rare occasions, a chief will unite a large number of Kindreds underneath him.

Kroot dwell in warm, temperate conditions on the worlds they inhabit, and construct large tree houses from animal hides, bound together by regurgitated dead wood. Some Kindreds prefer to reside in the ruins of the Imperium's hive cities on former Human worlds conquered by the T'au Empire.

The consumption of flesh is one of the key tenets of Kroot spirituality, as it is believed that the consumption of prey imparts the "spirit" of that prey to the Kroot, which is then passed on to the Kroot's children. This is the average Kroot's understanding of their species' biological ability to undergo rapid evolution through the absorption of other species' DNA, with the belief in "spirit" as a substitute for "genetic absorption."

As a part of this belief system, the Kroot believe that when a warrior dies, their spirit should be kept safe by the kindred. They will consider it their responsibility to consume the bodies of their dead foes, along with their own fallen dead and elders.

As one might expect, this custom is not viewed as an "honour" by the Human warriors of the Imperium and the Kroot are instead considered cannibalistic savages.


Vespid warriors

Vespid Stingwings wielding Neutron Blasters.

The Vespid are an insectoid alien race allied to the T'au who are native to the benighted gas giant world of Vespid. Vespid warriors, called Stingwings, form tactical units referred to as strains. Each strain is lead by an officer called a strain leader.

T'au Water Caste cadres established contact yet were unable at first to communicate with the species. This was not a mundane matter of vocalisation or the understanding of language, for the Vespids have an utterly alien mindset. Initially, the T'au were not only unable to communicate but incapable of getting the Vespids to even register that they were fellow sentients. As a result, little progress could be made beyond crystal trade agreements so the T'au could access the insectoids' advanced, crystal-based technologies.

The matter was eventually resolved at the command of the Ethereal Caste, who issued instructions for the construction of an interface device that forged a connection between the two species and facilitated communication.

The moment the device was employed, the Vespid not only registered the T'au as fellow sentients, they instantly understood the concept of the Greater Good and their place within it.

By gifting senior Vespids with "Communion Helms" fitted with the interface device, the T'au are able to communicate with the species at large. The will of the T'au Ethereals is disseminated to those Vespid under the command of these "strain leaders," and they become able to decipher their role as befits the Greater Good. Needless to say, certain factions within the Inquisition would very much like to learn more about the workings of this Communion Helm device, beleiving that it may actually be controlling the Vespid to some extent.

Because the Vespid language is so complex (presumably because of their complex mouthparts) and only the strain leaders are given the technological apparatus required to translate their language to their T'au allies, Vespid strains are very close knit and the T'au military relies heavily on strain leaders to help both sides coordinate.

Stingwing strains are highly sought after in T'au Hunter Cadres because of their high level of maneuverability. They are often used by T'au commanders alongside XV8 Crisis Battlesuits, or in scouting roles backing up T'au Pathfinders.

In the T'au Lexicon, the Vespids are referred to as Mal'kor, which comes from the Tau words "Mal" meaning "insect" and "kor" meaning "air".

Humans (Gue'vesa)

The T'au Empire hosts a growing population of Humans, known in the T'au Lexicon as Gue'vesa, who were once a part of the Imperium. Ranging from ideological defectors who hate the brutality and corruption of the Imperial government to captured Imperial Guardsmen and their children who have known no other life than that among the T'au, they have been fully incorporated into the empire.

While the Humans from recently conquered worlds are usually bitter at their defeat by xenos, they do often have T'au supporters amongst them from the start, and the number of these T'au sympathisers only grows larger as they realise the manifest economic benefits that the advanced technology of the T'au Empire can provide.

For the most part, the Gue'vesa are content and treated well, and are even allowed to continue the worship of the God-Emperor -- though the T'au Water Caste moves subtly among them to discourage this religion and replace it with reverence for the Greater Good.

Other Member/Allied Species

  • Nicassar - The Nicassar are a highly psychic ursinoid race and were the first alien species assimilated into the T'au Empire.
  • Demiurg - The Demiurg are a Prospect of the Leagues of Votann that has allied itself with the T'au and may also be important trading partners, as it was the Demiurg who first provided the T'au with the technology required to create Ion Weapons.
  • Tarellians - The Tarellians are dog-like aliens who often work as mercenaries for the T'au.
  • Galgs - The Galgs are green, scaled, frog-like creatures that often form into mercenary bands which fight for the T'au Empire.
  • Ji'atrix - The Ji'atrix are ethereal aliens skilled in void-faring.
  • Morralian - The Morralian are auxiliaries that employ their Deathsworn in service to the T'au.
  • Ranghon - The Ranghon are a race which has accepted the Greater Good and joined the T'au Empire.
  • Hrenian - The Hrenian are a species that often deploys light infantry auxiliaries that aid T'au military forces.
  • Poctroon - The Poctroon were the very first race to join the T'au but went extinct within a few generations due to a plague. The T'au settled their homeworld and turned it into the Sept World of Bork'an.
  • Nagi - The Nagi are a race of highly intelligent worms who have mind-control abilities from the world of Sha'galudd. Many serve as advisors to the Ethereals.

Member Species Homeworlds

  • T'au - T'au is the birthplace of the T'au and it is here that the Ethereal High Council, led by Aun'Va, convenes, its decrees shaping the entire empire. T'au remains the centre of T'au culture and bureaucracy, and produces many Fire Caste warriors. None can rival T'au for prestige, and only Vior'la can match its military and political power.

Spheres of Expansion

Tau Spheres of Expansion

The T'au Empire's first three Spheres of Expansion up to 998.M41.

The rise of the T'au can be seen to develop through five distinct phases, periods of intense growth known to the T'au as "Spheres of Expansion." Each of these waves of interstellar colonisation is marked by a long building up of resources, after which continual waves of exploratory missions are launched, followed, where needed, by military campaigns to solidify territorial gains.

Once a colony transforms itself into a stable settlement, it then serves as a jumping-off point for the next expansion. By the end of the millennia-long First Sphere Expansion, as it later came to be called, the T'au Empire had unfurled across the heavens and consisted of eight fully-settled and exploited star systems known as "septs."

Named after its primary or "Sept World," a sept can include any number of additionally colonised planets or moons in the same system, as well as other holdings such as listening posts, sensor fields, shield satellites, orbital cities, fortress stations and mining operations.

Everything is connected, both by a series of void stations and a massive net of communications and sensor relays strung between major locations within the system. Although it might take many generations to establish itself, each T'au sept is unique, with its own cultural nuances and varying proportions of the different castes and non-T'au alien populations.

T'au Septs

Each T'au sept, as a fully-settled T'au star system is known, has its own unique cultural identity, but remains wholly integrated within the greater T'au culture. This cultural identity seems to mainly derive from which T'au caste is more numerous and influential in the given sept.

Currently there are over twenty fully-developed septs within the T'au Empire. Each sept has its own sept icon or badge which serves as a "national" identifier of sorts for other T'au within the empire.

First Sphere Expansion Septs

The First Sphere Expansion of the T'au Empire began shortly after their species first achieved spaceflight capability. The T'au homeworld and the First Sphere colonies are of major economic and political importance to the T'au, and form the hub of the T'au Empire.

First Sphere Sept Icons

The icons of the septs founded during the First Sphere Expansion.

  • Tau'n - The first T'au sept established in the empire's history, Tau'n, has a chain of enormous orbital docks and controls the largest of the Air Caste void stations; every sept hosts warships of the T'au Protection Fleet (Kor'vattra), but none can boast of more than Tau'n.
  • D'yanoi - Named after the twin moons of its prime Sept World, D'yanoi has survived long isolation due to a space storm of fierce and unnatural qualities. It has also seen many infamous Ork invasions. Having been isolated for such a long period of time from the T'au Empire, its inhabitants are considered somewhat rustic and backwards.
  • Bork'an - The sept of Bork'an is a centre of T'au learning and academia, and its star system has many rich mining planets. Bork'an has a high percentage of Earth Caste in its population, and Fire Warriors from here are not infrequently outfitted with prototype weapons and support equipment.
  • Dal'yth - Dal'yth Sept was ravaged by the Imperium during the Damocles Crusade; many of its outer colonies and several cities on its prime Sept World were destroyed. It has recovered quickly, thanks to its busy trade ports. Large numbers of aliens can be seen here alongside its famously efficient Water Caste merchants and diplomats.
  • Fal'shia - Many technological innovations have come from this sept. Fire Caste warriors from Fal'shia are often the first to try out prototype weapons, armour and system upgrades.
  • Vior'la - The planet Vior'la orbits a binary star and its name translates as "hot-blooded" in Low Gothic. It is known to produce especially aggressive and skilled warriors. Many Ork invasions have been broken by the sept and the most respected Fire Caste academies reside upon Vior'la.
  • Sa'cea - The sept's prime Sept World of Sa'cea is the hottest and most densely populated of all T'au worlds; producing more colonisation fleets during the Second Sphere Expansion than any other. Warriors of Sa'cea are regarded as particularly honourable by other T'au.

Second Sphere Expansion Septs

The Second Sphere Expansion of the T'au Empire began in 018.M39, under the orders of Ethereal Supreme Aun'Wei of the Whispered Wisdom.

With new advances in propulsion technology and an already established interstellar empire, the second phase expansion was marked by more contact with aliens and larger wars.

Around 742.M41, the T'au Empire first came into conflict with the xenophobic Human Imperium, which launched the Damocles Gulf Crusade in order to keep the T'au's expansion into Imperial-controlled space in check.

The retreat of Imperial forces from T'au space marked the end of the Second Sphere Expansion. Of note are the septs established by the Fire Caste's Commander Farsight during this period.

Second Sphere Sept Icons

The icons of the septs founded during the Second Sphere Expansion.

  • Au'taal - Au'taal Prime is a a verdant and beautiful Sept World, where only honoured T'au heroes can retire.
  • N'dras For reasons known only to the Ethereals, this once thriving sept has largely been abandoned. Its remaining inhabitants are regarded as unstrustworthy, quick-tempered, and of a brooding countenance.
  • Ke'lshan - Situated near the Perdus Rift, this sept has suffered many invasions and is less trusting of aliens than other T'au. The Ke'lshan T'au Protection Fleet and Fire Caste forces have only recently been restored back to full strength after their clashes with Hive Fleet Gorgon. T'au from this sept have grown mistrustful, solemn, taciturn, unfriendly and sometimes openly hostile to alien races as a result of their experience with the Tyranids.
  • Elsy'eir -Elsy'eir is a densely populated sept with many moons orbiting its prime Sept World, most of which are mined for the valuable ores used in the construction of battlesuits. This sept is known for its poetry and artwork. Its citizens are considered intellectuals and well-respected for their creativeness by other T'au. The Earth Caste is dominant on Elsy'eir.
  • Tash'var - A frontier sept, the T'au of Tash'var have been subjected to frequent Ork invasions and pirate raids. As a result, its people have become tenacious and hardy.
  • Vash'ya - Known as the world "between spheres," this sept was settled near the end of the Second Sphere Expansion, as it took a long period for the Earth Caste's machines to make the air breathable. Major Air Caste fleets and many orbital defence platforms are docked around the system's Sept World.
  • T'olku - T'olku is known for its many large Ethereal temples, as well as the alien institutes, where many alien ambassadors are brought to be instructed in the ways of T'au culture, society and the Greater Good before being assimilated back into their respective homeworlds' societies.

Third Sphere Expansion Septs

The Third Sphere Expansion was begun by the T'au Empire on 977.997.M41 on the word of the Ethereal Supreme Aun'Va. The Fire Caste's Commander Shadowsun was placed in command of the expansion, and secured at least two new septs for the T'au Empire.

Tau Empire Galactic Map

A map of the T'au Empire at the time of the end of the Third Sphere Expansion in ca. 999.M41, prepared by the Air Caste.

During the Zeist Campaign of ca. 999.M41, Imperial Space Marine forces counterattacked against the Third Sphere Expansion, seemingly drawing it to a halt. However, by this time, the T'au Empire had grown to 133% of its size prior to 997.M41, largely as a result of the Imperium's distraction during the 13th Black Crusade and its aftermath in ca. 999.M41.

After the withdrawal of Imperial forces from the campaign, the Third Sphere Expansion continued until it ended following the disastrous Second Agrellan Campaign of ca. 999.M41 and increased resistance from the Imperium, which led to the assassination of the Ethereal Supreme Aun'Va.

Given the stated size increase of the T'au Empire during this early period, the Third Sphere includes many more septs currently unknown to Imperial scholars. Recognised T'au septs settled during the Third Sphere Expansion include:

Third Sphere Sept Icons

The icons of the septs founded during the Third Sphere Expansion.

  • Ksi'm'yen - The first of a handful of new septs founded in the Third Sphere Expansion, Ksi'myen is one of the many worlds previously claimed by the Imperium. Those Human inhabitants who swore fealty to the Greater Good have been resettled deeper into the T'au Empire to assure their safety and their proper assimilation into the empire. The T'au colonists of this sept seem to be associated with luck, subtlety and opportunistic subterfuge.
  • Fi'rios - The T'au occupying the prime Sept World of this sept wrested it from the grip of an Ork warlord, and cleansing the star system has proven quite costly. Fi'rios is a sept whose Air and Earth Caste pioneers are recognised by the wider empire for a tenacious refusal to accept defeat, tempered by a stoic acceptance of the price all must pay in the furtherance of the Greater Good.
  • Mu'gulath Bay - Mu'gulath Bay was formerly the Imperial Hive World known as Agrellan that was the gateway to the Dovar System. It was the site of a famous T'au victory at the Battle of Mu'gulath Bay, a victory won by both Commander Shadowsun and Ethereal Supreme Aun'Va which had marked the highpoint of the Third Sphere Expansion. After this victory, Mu'gulath Bay was well on its way to being established as a full-fledged sept. However, shortly after the Prefectia Campaign, the Imperium launched a major counterattack against Mu'gulath Bay, determined to reclaim it. In the end the T'au managed to resist, but the Imperium subjected the planet to an Exterminatus action and destroyed it. A small minority of Mu'gulath Bay's T'au population managed to survive the planetary firestorm unleashed by the Exterminatus thanks to an energy shield dome that was erected by the Earth Caste around a single T'au city, Lo'vash'tau. The survivors were faced with the unsettling truth that they might never be able to travel back to the T'au Empire as their world was now surrounded by Imperial forces. Mu'gulath Bay ultimately had to be abandoned as the entire Damocles Gulf was set ablaze by the Imperial counteroffensive, which effectively separated Imperial space from the T'au Empire. Surviving elements from Mu'gulath Bay then attempted to flee to the nearby Farsight Enclaves, but were set upon by Commander Surestrike on the order of the Ethereals, who were determined that the Farsight Enclaves should not see their strength grow. Surestrike managed to destroy most of the rebel T'au, but some still managed to escape.

Other T'au Worlds and Settlements

Since the T'au first left the atmosphere of their birth world, their empire has grown, spreading across the stars in three distinct phases known as "Spheres of Expansion."

In addition to the settled star systems, or septs, the T'au realm is rife with all manner of spatial phenomenon, T'au-made orbital structures, fortress stations, orbital cities, lesser void stations and important alien homeworlds. There are also more sparsely populated T'au colonies that are not accepted into the empire as full septs. Only a few names of such T'au colonies are known to the Imperium:

  • Arkunasha - The planet of Arkunasha was settled during the Second Sphere Expansion. Despite the aridity of the oxide deserts that made up the world's surface, the T'au had settled the red planet with a sizeable population. This they had achieved through the tireless work of the Earth Caste's scientists and engineers. By their efforts, the T'au Empire had girded the planet with two necklace-like strings of biodomes that ran around the most temperate latitudes, each a mirror distance from the equator. From orbit, the world appeared as a blood red globe adrift in the ocean of space, banded with two rows of bioluminescent lights that pulsed bluish white like the flanks of some deep-sea organism. In their preliminary investigations, during the earliest expeditions to Arkunasha's surface, the Earth Caste had made a disturbing discovery. Whilst determining the source of the oxide deserts that covered the world, they found a great variance in the metallic composition and even origin of the various particulates. It was as if the world had been entirely covered in metal structures at some time in the distant past, which had long since been utterly ground to dust. Given the depth of the oxide residue, that ancient civilisation must have included several artificial cities the size of mountain ranges. Theories abounded throughout the Earth Caste about the planet-wide catastrophe that had torn everything upon the planet's surface apart. Though the T'au had no idea what might have caused Arkunasha's spectacular death, or who the inhabitants might have been, they had taken their first glimpse of the world-destroying power of the Imperium's Exterminatus actions.
  • Dal'yth - Before the coming of the T'au, the indigo planet of Dal'yth was a wild ecosystem of deep blue foliage and slithering, segmented beasts. It was tamed long ago, during the First Sphere Expansion, and has been brought into compliance with prime-level colony standards ever since. Because of the high proportion of Water Caste members upon its surface, Dal'yth has enjoyed extremely beneficial trade agreements, and has recently been counted as one of the Nineteen Wonders of the T'au Empire. Much of the planet's surface is covered with a tessellating hexagonal net of cities and sub-cities, each connected to the nearest conurbations by a splaying and perfectly regular network of transit tubeways. Clean, white magnorail trains whisk the populace to and fro, detaching and picking up carriages with slingshot efficiency so that they never have to stop. Though the planet has landscaped hills and even gigantic hexagonal reservoirs dotted across it, from orbit, it looks as if the T'au have settled it with the precision of an Earth Caste scientist modelling a new atomic phenomenon.
  • Es'Tau - Es'Tau was settled during the Second Sphere Expansion.
  • Ho'sarn - The T'au colony of Ho'sarn was evacuated in 902.M41 as Hive Fleet Gorgon approached, but the evacuation fleet was ambushed by the hive fleet's bioships and completely slaughtered.
  • Isla'su - Isla'su is the watery homeworld of the Greet, often considered part of the Fal'shia Sept.
  • Ka'mais - Ka'mais was invaded by the Tyranids' Hive Fleet Gorgon in 902.M41. A hidden Necron fleet emerged from Ka'mais' dead moon and destroyed the outnumbered Tyranid bioships, but then continued to land on Ka'mais and eradicate the planet's population to retake the world for the Necrons' own.
  • Kor'vattra (T'au Protection Fleet) and Kor'shuto (Orbital Cities) - Incorporated into every sept are dozens of major docks for the T'au Protection Fleet (Kor'vattra), but in addition to these immense void stations, many septs have also developed vast orbital cities (Kor'shuto). These can be moved to provide stable "jumping off" points for large T'au research endeavours, military campaigns or major colonisation efforts.
  • Me'lek
  • Red Sun Systems - T'au probes have marked the dense cluster of planets around a string of six distinct red suns; however, the massive Ork population has deterred any further T'au colonisation of the region. The star systems are ringed with T'au sensor buoys, in hopes of offering early warning should the Greenskins ever cease their internal fighting and seek to menace neighbouring systems.
  • Sha'draig - Sha'draig was invaded by the Tyranids of Hive Fleet Gorgon in 900.M41. The Tyranids were eventually driven off the world, but not before it was almost completely consumed by Ripper swarms.
  • T'ros - T'ros was recently settled during the Third Sphere Expansion. This was an Imperial world that was willingly annexed by the T'au after opening commercial relations with the xenos empire. The resulting Imperial attempt to retake the world was defeated by the T'au during what became known as the Taros Campaign.
  • Ta'shiro (Fortress Stations) - Positioned in the deep space between septs are T'au Ta'shiro bases -- fortress stations capable of enough thrust to resist gravitic drift and maintain permanent interstellar positions. Several patterns of development have been followed in the construction of these enormous floating fortresses -- with the largest comparable in population to a continent-sized city.
  • Zone of Silence - A devastated region where Hive Fleet Gorgon left behind many barren planets scoured of all life forms.

Non-T'au Worlds

During the First Sphere Expansion the homeworlds and colonies of the Kroot and of the Vespid were also incoporated into the T'au Empire. Notice that these star systems are not considered septs by the T'au.

In addition there are an unknown number of former Imperial worlds within the T'au Empire, some or all of which might still have a Human population (see Gue'vesa above):

  • Pech - The Kroot are the most common of the alien auxiliaries in service to the T'au Empire, and dozens of Kroot enclaves can be found among the septs. Although they are a far-flung and migratory species, all Kroot eventually feel the pangs that lead them to return to their birth world -- the true home of all Kroot Kindreds, the world of Pech. There are eight star systems in the T'au Empire inhabited by the Kroot, including Pech. The Imperium knows only the name of the planet Krath, where the T'au first encountered the Kroot.
  • Roksh XVI - Roksh XVI is the site of a secret T'au listening post. The planet was part of the Roksh System that was home to the Rokshashi Wealthweb merchant guild before the entire star system was consumed by the Tyranid Hive Fleet Gorgon in 689.902.M41.
  • Sha'Galudd - Sha'Galudd is the homeworld of the Nagi, a small xenos species of highly intelligent worms known for their mind control abilities. When first discovered by the T'au, the Nagi were hated creatures known as "mindworms," but since the early violent conflicts, they have agreed to a peace accord and joined the T'au Empire. Many Nagi now serve as valued advisors to the Ethereal Caste.
  • Vespid - Vespid is a benighted gas giant that also just happens to be the homeworld of the insectoid Vespid species. This world is also known for its rich crystal mines. The Earth Caste discovered the Vespid crystals have many intriguing technological uses.

Artefact Worlds

Three so-called "artefact worlds" are located within the borders of the T'au Empire. As the name indicates, ancient artefacts of unknown origin have been discovered on these planets. It is not known if these worlds possess established T'au colonies.

  • Arthas Moloch - The artefact world of Arthas Moloch is as grey and desolate as a tomb. Its surface is jumbled with thousands of tumbledown shrines and strange, faceless statues that predate any of the Human colony worlds of the Imperium. The world's surface is cracked and broken, giving the sense that the planet itself died long ago -- an impression that is reinforced by the fact that not a single green shoot or patch of moss can be found anywhere on its surface. Not a single living soul makes a home there, though the plaster walls of the planet's tombs bear the dark brown smears of bloodshed, and ghostly shadows have been burnt into the walls wherever the ruins cluster close together. Though the world is barren as bone, if one possessed of psychic abilities were to behold it with the witchsight, it would shine like a gold mine in firelight. The shrine-hold is peppered with artefacts of ancient and mysterious origin, each a priceless wonder left discarded in the dust. Arthas Moloch is also known as a Dead World to the Imperium and it is where Commander Farsight discovered the Dawn Blade.
  • Q-15
  • Landfall

Farsight Enclaves

Farsight Enclaves Symbol

Icon of the rebel T'au Farsight Enclaves established by Commander Farsight.

Although not a part of the T'au Empire, this breakaway T'au faction led by Commander Farsight is known to have settled beyond the region known as the Damocles Gulf, and is named the Farsight Enclaves. These enclaves still believe in the Tau'va, the philosophy of the Greater Good, but operate without the guidance of the Ethereals.

The exact names of these Fire Caste-led septs are unknown to the wider T'au Empire, as the armed fortress stations defending them have proven effective at destroying any probes sent to the Enclaves. When sighted generations later, these forces and fleets bore markings similar in design to those used by the T'au Empire, but in colours and patterns never sanctioned by the Ethereals.

Like any distant T'au colony, much of the wargear, support equipment and armour used by those within the Farsight Enclaves is slightly dated -- the equipment most prevalent at the time of Commander Farsight's disappearance several Terran centuries ago. There has been, however, unsettling evidence of classified technology and recent T'au prototypes present within the Farsight Enclaves.

Time will tell whether this is the result of spycraft, theft or defectors from the T'au Empire who have been aiding those within Farsight's domain.

Forces of the T'au Empire

T'au Empire Forces
Command EtherealT'au CommanderCadre Fireblade
Troops Fire Warrior (Fire Warrior Strike TeamFire Warrior Breacher Team) • PathfinderDrone Squadron
Battlesuits XV02 Pilot BattlesuitXV8 Crisis Battlesuit (XV8-02 Crisis Iridium BattlesuitXV81 Crisis BattlesuitXV84 Crisis BattlesuitXV85 Enforcer BattlesuitXV86 Coldstar BattlesuitXV89 Crisis BattlesuitXV88 Broadside Battlesuit) • Stealthsuits (XV15 StealthsuitXV22 StealthsuitXV25 StealthsuitXV95 Ghostkeel Battlesuit) • XV46 Vanguard Void BattlesuitXV9 Hazard Battlesuit • Class 10 Battlesuits (XV104 Riptide BattlesuitXV107 R'varna BattlesuitXV109 Y'vahra Battlesuit) • KV128 StormsurgeKX139 Ta'unar Supremacy Armour
Grav-Vehicles DevilfishDrone HarbingerHammerheadSky RaySwordfishTX-4 PiranhaTX-42 PiranhaTetra
Aircraft BarracudaMantaOrcaRazorsharkDX-6 Remora Drone Stealth FighterSun SharkTiger SharkTiger Shark AX-1-0
T'au Auxiliaries Kroot ShaperKroot Carnivore SquadKroot HoundKrootoxKnarlocGreat KnarlocVespid StingwingsGue'vesa
Notable T'au Aun'VaAun'ShiCommander FarsightCommander PuretideCommander KaisCommander ShadowsunSub-Commander DarkstriderShas'el LushaShas'la T'au KaisShas'la LongstrikeCommander Arra'konCommander BravestormCommander BrightswordCommander Sha'vastosSub-Commander TorchstarHonour-Shas'Vre O'VesaShas'vre Ob'lotai 9-0

Notable T'au

  • La'Kais (possibly Shas'O Vior'la Kais later on)
  • Shas'O Vera
  • Aun'rai


Game Use

In the Warhammer 40,000 tabletop miniatures game, the T'au are a powerful ranged army. An effective tactic is to engage the enemy at the maximum range of T'au weaponry, which typically has longer ranges and greater firepower than the equivalent weapons of other armies. As such, the T'au have weaker close combat abilities. Thus, many T'au tactics involve staying at a distance, to wipe out the enemy or to redeploy swiftly to further engage the opponent at range.

A more prevalent tactic amongst T'au veterans is the "Mecha-T'au" approach, which utilises the inherent mobility and speed of T'au vehicles and battlesuits to confuse and overwhelm the enemy by engaging them at all levels of the battlefield.

The T'au Empire army is highly specialised, with each element normally having a specific task carried out in the support of the rest of the force. Fire Warriors make up the line infantry, while forward scouts known as Pathfinders scout enemy positions, and provide fire support with Rail Rifles and Marker Light target designators. The T'au also deploy battlesuits in support roles, such as providing specialised weapons to deal with any hot spots on the battlefield, providing heavy anti-tank fire, or as stealth infiltrators, operating independently of the main force.

The T'au also make extensive use of small AI-controlled Drones, typically equipped with firearms or shield projectors. These Drones can be used to protect teams of Fire Warriors, battlesuits and support vehicles.

The basic weapons of the Fire Caste are Pulse Weapons, which propel a particle beam that breaks down into a plasma pulse as it is fired from the firearm. This is commonly used as a long-range Pulse Rifle or a portable Pulse Carbine. A rapid-fire variation of the carbine is also used on vehicles and battlesuits, and is known as the Burst Cannon.

The T'au are known to use Ion Cannons and Railguns on their voidships and vehicles, as well as various guided and unguided missiles. They also arm their battlesuits with a variety of weapons, ranging from Burst Cannons and Missile Pods, to Fusion Blasters, Pulse Rifles, and Flamers.


The name "T'au" is taken from the letter of the Greek alphabet with the same name, tau.

See Also


  • Apocalypse (5th Edition)
  • Battlefleet Gothic Magazine 17, "Tau In Space," "The Tau Empire," pp. 6-17, 25-27
  • Codex: Leagues of Votann (9th Edition), pp. 6, 31
  • Codex: Space Marines (5th Edition), pg. 48
  • Codex: Tau (3rd Edition), pp. 8-9, 16, 22, 24, 26, 30, 50-51, 61
  • Codex: Tau (4th Edition), pp. 9, 32, 34, 40, 44-47
  • Codex: Tau Empire (6th Edition), pp. 8-12, 22-24
  • Codex: Tau Empire (7th Edition), pp. 15-16
  • Codex: T'au Empire (8th Edition), pp. 6-41
  • Codex: Tyranids (5th Edition), pp. 18-21
  • Deathwatch: The Achilus Assault (RPG), pp. 109-130
  • Deathwatch: Core Rulebook (RPG), pg. 315
  • Deathwatch: The Jericho Reach (RPG), pp. 56-63, 66-67, 69-71, 91-95, 98-99, 104-106, 108
  • Deathwatch: Mark of the Xenos (RPG), pp. 8-31
  • Deathwatch: Rising Tempest (RPG), pp. 5-13, 15-17, 118-119, 123, 130-131, 139-140
  • Farsight Enclaves - A Codex: Tau Empire Supplement (6th Edition)
  • Imperial Armour Volume Three - The Taros Campaign, pp. 1-146
  • Planetstrike (5th Edition), pg. 57
  • Warhammer 40,000: Rulebook (4th Edition), pg. 128
  • Warhammer 40,000: Rulebook (5th Edition), pg. 129
  • Warhammer 40,000: Rulebook (8th Edition), pp. 132-135
  • White Dwarf 261 (US), "Tau: A preview of the new race for 40k"
  • White Dwarf 262 (US), "Index Xenos: For the Greater Good, an Investigation into the Newly Discovered Tau Empire"
  • White Dwarf 314 (UK), "Tau Empire: Preview"
  • White Dwarf 315 (UK), "Battle Report: Death on Kol’n - Tau vs. Dark Eldar"
  • White Dwarf 316 (UK), "Index Xenos: Vespids"
  • White Dwarf 317 (UK), "Eavy Metal: Heroes of the Tau Empire"
  • White Dwarf 40 (December 2019), "Worlds of Warhammer" by Phil Kelly, pg. 10
  • Last Chancers (Novel Series) by Gavin Thorpe

Raven Rock Videos
Warhammer 40,000 Overview Grim Dark Lore Teaser TrailerPart 1: ExodusPart 2: The Golden AgePart 3: Old NightPart 4: Rise of the EmperorPart 5: UnityPart 6: Lords of MarsPart 7: The Machine GodPart 8: ImperiumPart 9: The Fall of the AeldariPart 10: Gods and DaemonsPart 11: Great Crusade BeginsPart 12: The Son of StrifePart 13: Lost and FoundPart 14: A Thousand SonsPart 15: Bearer of the WordPart 16: The Perfect CityPart 17: Triumph at UllanorPart 18: Return to TerraPart 19: Council of NikaeaPart 20: Serpent in the GardenPart 21: Horus FallingPart 22: TraitorsPart 23: Folly of MagnusPart 24: Dark GambitsPart 25: HeresyPart 26: Flight of the EisensteinPart 27: MassacrePart 28: Requiem for a DreamPart 29: The SiegePart 30: Imperium InvictusPart 31: The Age of RebirthPart 32: The Rise of AbaddonPart 33: Saints and BeastsPart 34: InterregnumPart 35: Age of ApostasyPart 36: The Great DevourerPart 37: The Time of EndingPart 38: The 13th Black CrusadePart 39: ResurrectionPart 40: Indomitus