The Ethereals are the supreme ruling caste of the T'au Empire, a mysterious order of leaders whose authority over the other castes is absolute and unquestioned. Known to their own kind as the Aun, they emerged in T'au history to unite a fractured people, and ever since their word has guided the destiny of the entire race toward the Greater Good.
The origins of the Ethereals remain shrouded in mystery, even to the T'au themselves. They command a devotion that borders on the instinctive; in their presence, warriors fight with redoubled zeal and the faltering find fresh resolve. Some Imperial scholars speculate they wield an unknown power, pheromonal or psychological, that compels obedience, though the truth is jealously guarded.
Ethereals rarely expose themselves to danger, for the death of even one is a catastrophe that can shake an entire Empire. When they do walk the battlefield, their mere presence can turn a wavering assault into an unstoppable tide of disciplined fury.