The Tau '''==Overview==Each caste system''' divides all [[Tau]] into 5 groups known as castes. The castes are is named after the elements an element of nature, symbolising the purpose and closest to temperament of the particular caste in question's members. Movement between the castes seems to be impossible, and membership A T'au's caste is determined at birth and inherited by one's parents. Inter-breeding is forbidden by the Etherals[[Ethereal]]s. For a T'au to choose another caste for himself seems to be impossible, and held contrary to the notions of the [[Greater Good]]. The castes are based upon the racial and political divisions that separated the Tau on their [[homeworld]] of [[T'au (Planet)|T'au ]] during the time of the [[Mont'au]]. The Castes were first formally established after the Ethereals brokered peace between warring T'au factions at [[Fio'taun]]. Emphasizing the need for the Greater Good, the Ethereals decreed that the T'au would be formalized into castes, each known by the element that most befitted its role in the new T'au society.{{Fn|6a}}

|style="background:#4F4F4F 630; color: white" colspan=1 align=center|'''order and name of Caste\Rank'''|style="background:#630; color: black" colspan=1 align=center|Trainee rank— '''SAAL'''{{Fn|1}}|style="background:#4F4F4F 630; color: black" colspan=1 align=center|Lowest rank — '''Fire - ShasLA'''|style="background:#4F4F4F 630; color: black" colspan=1 align=center|Second lowest rank — '''Earth - FioUI'''|style="background:#4F4F4F 630; color: black" colspan=1 align=center|Middle rank — '''Water - PorVRE'''|style="background:#4F4F4F 630; color: black" colspan=1 align=center|Second highest rank — '''Air - KorEL'''|style="background:#4F4F4F 630; color: black" colspan=1 align=center|Highest rank — '''Etheral or Celestial - AunO'''

|style=background:#c96; align=center|trainee rank [[Fire Caste|Fire - SAAL¹Shas]]|align=center|Underling|align=center|unknownWarrior|align=center|unknownVeteran|align=center|unknown Hero|align=center|unknown Noble or Knight|align=center|unknownCommander

|style=background:#c96; align=center|lowest rank [[Earth Caste|Earth - LA Fio]]|align=center|Apprentice|align=center|warriorWorker|align=center|workerSenior|align=center|bureaucratOverseer|align=center|messengerEngineer|align=center|princePlanner

|style=background:#c96; align=center|second lowest rank [[Water Caste|Water - UI Por]]|align=center|Assistant|align=center|veteranBureaucrat|align=center|seniorEnvoy|align=center|envoyMagister|align=center|carrierDiplomat|align=center|prelateAmbassador

|align=center|middle rank - VRE|align=center|hero|align=center|overseer|align=center|magister|align=center|pilot|align=center|king|-|align=center|second highest rank - EL|align=center|noble or knight|align=center|engineer|align=center|diplomat|alignstyle=center|captain|background:#c96; align=center|holy(?)[[Air Caste|Air -Kor]]|align=center|highest rank - ODeliverer|align=center|commanderMessenger|align=center|plannerCarrier|align=center|ambassadorPilot|align=center|admiralCaptain|align=center|highest(?)Admiral

==Shas - Fire casteCaste==*{{main|Fire Caste}}[[Image:FireCaste.jpg|thumb|right|60px|Fire Caste symbol{{Fn|6a}}]]Members of the '''Fire caste Caste''' are the warriors of the [[Tau T'au Empire]], and as such are most often seen on the field of battle. They are taller have been bred to be the strongest and stronger than the members of the other castesmost aggressive T'au, although still weaker and shorter than the average humanweak strains are quickly weeded out. These traits come from the Fire Caste's origin on the plains of [[T'au (Planet)|T'au]], the Tau home world, where they were hunters and warriors. Tau [[Fire Warriors]], as soldiers of the Fire Caste are known, spend their entire lifetimes in battle or preparing for it, constantly honing their tactics and working to improve their skills. The strongest of the strong are those T'au from the [[T'au Sept|world ]] of [[Vior'la]] tend to , who have slightly greater muscle mass because of the increased gravitational pull stronger gravity of that planet.{{Fn|6a}} The Fire Caste are guided by the planet[[Code of Fire]] — a doctrine of loyalty, martial arts and merciless war tempered by wisdom.{{Fn|6a}}{{Fn|9a}}

===rising through the ranks=Fio - Earth Caste==Provided the warrior survives 4 years of ''active duty'', he undergoes the first *{{main|Earth Caste}}[[Trial by FireImage:EarthCaste.jpg|thumb|right|60px|Earth Caste Symbol{{Fn|6a}}]]This caste provides for the manufacturing, agricultural, industrial, which can be anything from mere gladiatorial affairs to trial by constant combatartisans, and engineering needs of the T'au Empire. The higher one's rank within By far the Fire Castelargest caste in sheer numbers, the more likely one it is to be a [[Battlesuit]] pilotthey who erect dwellings, provide food, and produce new technology. Upon attaining Members of the rank of '''"O"'''Earth Caste are often described as plain and dour, possessing a member of rather stoic outlook on life in general. They were originally the Fire Caste may be allowed first T'au to retire active duty build cities and become an advisor to the Tau military's command structure, the practice agriculture. The city of [[ShasFio'ar'toltaun]]. Other than death is an example of this is , being the only way to leave first place where the Tau military[[Ethereal]]s appeared.{{Fn|6a}}

{{Clear}}==Fio Por - Earth Water Caste==This caste provides for *{{main|Water Caste}}[[Image:WaterCaste.jpg|thumb|right|60px|Water Caste Symbol{{Fn|6a}}]]The Water Caste serve the manufacturingT'au Empire as traders, agriculturalmerchants, and engineering needs of the Tau Empirepublic servants, including being the buildersbureaucrats, farmersadministrators, scientistsdiplomats, and engineersambassadors. They interact with other races when such affairs are not handled by the Fire Caste, and often described act as plain administrators of T'au worlds in the absence of an [[Ethereal]] governor. Like water, Water Caste bureaucrats fluidly move between other Castes and douralien races incorporated within the Empire to make sure that it flows smoothly. The Water Caste are known for their great linguistic, diplomatic, possessing a rather stoic outlook on life in generaland negotiation skills. They were originally Members of the Water Caste are often the ones who initiate first Tau contact with new species encountered by the Empire, skilfully negotiating their union with the T'au.{{Fn|6a}} The members of the Water Caste have a gift for linguistics that has become more and more developed over time, so they able to build cities learn alien languages with ease and practice agricultureshow a remarkable ability to emulate and pick up subtlest of communication features. {{Fn|9a}} The city of Water Caste also employs criminal investigators known as [[FioKar'tauntyr]] is an example of this, being the first place where the Ethereals appeared.{{Fn|11}}

*{{main|Air Caste}}[[Image:AirCaste.jpg|thumb|right|60px|Air Caste Symbol{{Fn|6a}}]]The Air Caste is charged with holding the Tau T'au Empire together through the [[Kor'vattra]], the Tau T'au Empire's merchant and warfleetwar-fleet in addition to operating [[Tau Orbital]]s and [[Fortress Station]]s. They function not only Formerly functioning as messengers, but these days they are also the Tau T'au Navyand are sometimes called the "Invisible Caste", for they rarely if ever set foot upon planets. The Tau Living in [[Orbital City|Orbital Cities]], T'au of the Air Caste are the tallest and most slender of all TauT'au, with long, skinny limbs and hollow bones developed due to lives lived mostly in low- and zero-gravity ships and space stations. In the past, before the time of the [[Mont'au]], the Tau T'au that originally became the Air Caste had membranes stretching between their limbs, allowing them to glide on air currents. Tau T'au pilots tend to be superior pilots compared to humans their [[human]] counterparts because they have a better depth perception and higher G-tolerance, but lack battle-experience compared to the best Imperial fighter-pilots.{{Fn|6a}}

==Por - Water caste==The Water Air Caste serve the Tau Empire as traders, merchants, diplomats, and ambassadors. They interact with other races when such affairs are not handled by the Fire Caste. The Water Caste tend to be tall and slender compared to other Taualso operates air defences within T'au territory.{{Fn|13}}

*{{main|Ethereal}}[[Image:Ethereal Caste.jpg|thumb|right|60px|Ethereal Caste Symbol{{Fn|6a}}]]The [[Ethereal|Ethereals]], these mysterious Tau, s serve as "philosopher kings" , and guide the other castes , as well as Tau Empire alien member-races of the T'au empire, towards the enlightenment of the ''[[Tau'va]]''; , the [[Greater Good]].They serve as the undisputed rulers of the T'au Empire. Their unique role is a combination of spiritual and political duties, and their declarations shape and steer every action of the Empire. Were an Ethereal to order a T'au to kill himself, he would be met with instant obedience.{{Fn|6a}} Ethereals themselves rule from the [[Ethereal Council]], with the [[Ethereal Supreme]] being the highest ranked of the Caste. They are in turn protected by the [[Ethereal Guard]].{{Fn|16}}

*¹[[Fire Warrior (Novel)]] page 120 (the canonicity of the information contained in the novel is unclear){{Tau}}