The Ethereal Caste, known in the T'au tongue as the Aun, stands above and apart from the other castes as the unquestioned leadership of the entire Empire. Their emergence in the deep past is credited with ending the ruinous wars between the T'au tribes and uniting them beneath the philosophy of the Greater Good, and their word has shaped every facet of T'au civilisation ever since. Guided by the Ethereal High Council upon distant T'au and its presiding Aun'o, they bind caste to caste with an authority at once spiritual and absolute.
Seldom does an Ethereal descend to the battlefield, for their lives are precious beyond reckoning, yet when one does the effect upon the Fire Caste is profound. In the presence of an Aun, T'au warriors shrug off fear and fatigue alike and press themselves to feats they would never dare alone, so complete is their devotion to the leader in their midst. Every T'au upon that field would gladly lay down their life sooner than fail the Ethereal they serve.
When honour or dire need demands it, an Ethereal takes up the honour blade, a broad-headed halberd upon a slender haft that is the emblem of their office. In peace such weapons settle disputes among the Aun through stylised, bloodless duels closer to shared meditation than to combat, but in war they can be turned upon the enemies of the Greater Good, wielded with a serene precision that belies the caste's gentle reputation.
Order of battle
