The Ethereals, called Aun in the T’au lexicon, are the ruling caste of the T’au Empire. They arrived late in T’au history, ended a war between the ancestors of the Fire and Earth Castes, and introduced the Greater Good, the philosophy that holds the empire together. Their word is law, and no one can explain why.
Who the Ethereals are
Ethereals are philosophers, mystics, and leaders who guide T’au society politically and socially. They see their role as keeping the castes aimed at the Greater Good and stopping them from sliding back into the savagery that nearly destroyed them. They hold the highest rank in the empire, and other T’au don’t question their authority.
They weren’t part of the earliest T’au myths. They first appear in the story of the siege of Fio’taun, where the plains T’au (later the Fire Caste) fought the city of Fio’taun (later the Earth Caste). The Ethereals talked both sides down, convinced them to follow the Greater Good, and unified the T’au tribes. That moment is treated as the birth of the T’au Empire.
Ethereals lead from the front of T’au society, but they also sometimes join battles to inspire Fire Warriors. Their presence pushes T’au to feats of honour, and they’re credited with keeping the castes pointed in the same direction ever since.
- Called Aun in the T’au lexicon.
- First appeared during the siege of Fio’taun.
- Credited with unifying the T’au tribes under the Greater Good.
- Serve as philosophers, mystics, and commanders.
- Hold the highest social and political rank in the empire.
Authority and obedience
An Ethereal’s command is absolute. A T’au will gladly die if ordered to, quickly and without hesitation. That loyalty seems natural to the T’au themselves, but other races find it deeply unsettling, and humanity in particular has spent a long time wondering why the T’au obey like that.
Nobody has proof of how it works. The leading theories are prenatal indoctrination, pheromonal compulsion, some hidden psychic gift, or something stranger still. Captured Ethereals have been interrogated and have been less than forthcoming, and the T’au show no interest in studying the effect themselves.
Inquisitor Maturin Ralei once pressed a captured Ethereal about Commander Farsight’s breakaway Enclave, pointing out that Farsight built a thriving state without any Ethereal authority, which undercuts the idea of natural unity under the Greater Good. The Ethereal refused to answer.
| Theory | Status |
|---|---|
| Prenatal indoctrination | Unconfirmed |
| Pheromonal compulsion | Unconfirmed |
| Psychic gift | Unconfirmed |
| Other esoteric control | Unconfirmed |
On the battlefield
Ethereals rarely put themselves in direct danger, but when they take the field they’re force multipliers. Their presence drives nearby T’au to push for objectives even when it means certain death, and T’au will fanatically throw themselves in front of danger to protect one.
It cuts both ways. If an Ethereal falls, the T’au around them are hit with grief and rage so severe that the battle plan tends to collapse. Losing one in combat can break the army’s morale entirely.
When they do fight, Ethereals are well protected. They’re accompanied by Ethereal Guard for close protection, carry an Equalizer and an Honour Blade, and often have Drone escorts, sometimes including a Hover Drone for personal transport.
- Ethereal Guard provide close protection.
- Armed with an Equalizer and an Honour Blade.
- Frequently accompanied by Drones.
- Hover Drones offer personal transport.
- Aun’shi is one of the best-known Ethereals.
Biology and secrets
Ethereals have a small, diamond-shaped organ on their foreheads. Its purpose is unknown. Magos Biologis Sharle Darvus dissected one under Inquisitor Brehm Sasham’s orders, but details of that study remain classified or lost.
What the Ethereals know about their own nature, and about events like Farsight’s breakaway, stays locked behind their silence. Ralei’s interrogation shows they’d rather say nothing than explain.
Key facts
- Ethereals are the ruling caste of the T’au Empire, also called Aun.
- They first appeared during the siege of Fio’taun and introduced the Greater Good.
- Their authority over other T’au is absolute and unexplained.
- They sometimes lead Fire Warriors in battle, boosting morale.
- They have a mysterious diamond-shaped organ on their foreheads.
- If an Ethereal dies in combat, nearby T’au are devastated.
FAQ
What is the T’au Ethereal caste?
The Ethereal caste, or Aun, is the ruling class of the T’au Empire. They lead society, guide the Greater Good, and sometimes command armies.
Why do T’au obey Ethereals so completely?
No one knows for sure. Theories range from pheromones to psychic powers, but none have been confirmed. The T’au themselves don’t question it, and captured Ethereals won’t explain.
Do Ethereals fight in battles?
They rarely seek combat, but when present they inspire T’au to fight harder, even to certain death. Their death can shatter the morale of the T’au around them.
What happens if an Ethereal dies in battle?
The T’au nearby are overwhelmed by grief and anger, and their battle plans often fall apart. That’s the risk of bringing one to the front.