The Defence of Fio'vash is a tale oft-told to the Fire Caste about the famed Ethereal Aun'shi. In what was supposed to be his last assignment, Aun'shi led a Tau colony force to a planet he named Kel'tyr, the newest world in the expanding Tau Empire. Infested by Feral Orks, initial progress in claiming the world was slow but, under Aun'shi's guidance, the Fire Caste were soon able to push the Orks back from the main areas of Tau settlements. Within four Terran years, the world was flourishing, the Earth Caste building many fine towns across the main continental mass. Fio'vash was one such town, a mining outpost in the low foothills of a mineral rich mountain range some four hundred Terran miles to the east of the planetary capital. While on a tour of inspection of the outlying towns, Aun'shi and his bodyguard became trapped in Fio'vash when a horde of Feral Orks surrounded the town and launched a surprise attack to capture the mine workings.
The existing garrison of Fio'vash had been augmented by Aun'shi's Fire Warrior bodyguard and the Orks were cut down in the hundreds. Early in the fighting, the Shas'vre of the Fire Warriors was beheaded, slain by an enormous Ork Nob. The loss of this heroic warrior sent a surge of panic through the ranks of the Tau warriors and it seemed as though their defences would crumble. Aun'shi leapt in front of the Nob and cut him in two with one blow from his Honour Blade, planting the haft of his weapon between the shorn halves of the corpse. Heartened by the Ethereal's brave defiance, the Fire Warrior line steadied and they threw the Orks back. Again and again the Orks attacked Fio'vash and each time Aun'shi lead the defenders in battle, fighting alongside his warriors and spurring them to unheard of feats of valour. He dispatched stealth-armoured warriors and a member of the Air Caste to take word to the capital, as he knew that against so many Orks, it was only a matter of time until they were overrun.
The battle raged on, the Tau defenders silhouetted by the flames of burning buildings. The Fire Warriors were fighting at the limits of courage and endurance, held together by the indomitable will of Aun'shi. Every time their line bent back under the Ork assault, Aun'shi was there, his flashing blade a shimmering blur of silver steel as he cut down Orks by the dozen. He moved like quicksilver, dodging killing blows, twisting and weaving through the air in a graceful ballet of death. Wherever he struck, Orks died and soon none would go near him, so fearful were they of this warrior who could not be killed. Eventually the Tau were forced to pull back to an inner perimeter of defensive walls the Earth Caste had constructed, and there they prepared for the next assault. Aun'shi stood in the ranks with the surviving Fire Warriors, hoping that the Air Caste had managed to carry word of their situation to the capital.
The Greenskins attacked again and, though the Fire Warriors slew scores of Orks with every volley, they simply could not kill enough to prevent them from reaching the walls. All through the burning heat of the day, Orks charged the defensive walls, the mound of dead before it growing every second as the Fire Warriors killed with grim efficiency. The walls were beginning to give in places and the Orks poured through these gaps whenever they appeared, swamping Tau Battlesuits and dragging them to the ground. Each time the Orks formed a wedge within a breach, Aun'shi led a counterattack to hurl them from the compound. As dusk approached, less than fifty Fire Warriors remained alive and both forces sensed that the end was near. As the Orks massed for the final attack, Aun'shi ordered a retreat into the barricaded shrine at the town's centre, knowing that there were too few of them to hold the full length of the wall. The Fire Warriors readied their last magazines of ammunition while the workers of the Earth Caste took up their picks and shovels, ready to fight in hand-to-hand combat.
With a roar of pure hatred, the Orks swarmed over the wall and into the compound, burning and destroying everything in their path. Fire Warriors shot from prepared loopholes, thinning the first wave of Orks, but unable to prevent them from reaching the building. Orks set about the door to the shrine with giant axes, climbing the walls to smash the roof and screaming their bestial war-cries. The first Orks to enter the shrine were killed swiftly, but there were always more pushing their way inside. Aun'shi fought at the shrine doors as they were finally ripped from the frame. Together with the last of his Fire Warriors, Aun'shi stood ready to fight, his Honour Blade cleaving the air before him in long sweeping slashes. If they were to die, then they would die together.
Suddenly the Orks were thrown into silhouette as a series of rippling detonations exploded behind them. Sweeping through the flames came the bulky forms of dozens of Devilfish troop carriers, guns chattering with deadly firepower as team after team of Fire Warriors poured from their interiors. Alerted by the Air Caste, the full wrath of the Tau now fell upon the Ork rear. Lumbering XV88 Broadside Battlesuits sprayed the Orks with fire, cutting them down in droves as Hammerhead tanks blasted huge holes in the Ork mobs. Within the solar hour, the Orks were either dead or fleeing, and the leader of the recently-arrived Fire Caste cadres found Aun'shi still standing at the shrine doors, his blade slick with Ork blood, and a handful of his bodyguards left alive. Despite the terrible casualties, the defence of Fio'vash was hailed as a great victory; the Ethereal shrine still stood and the mine workings were still in Tau hands. The survivors of the siege hailed Aun'shi as a hero, pledging to serve him for the rest of their lives.
News of the victory soon reached the Ethereals on T'au, and rather than allow Aun'shi to spend his remaining years on Au'taal, it was decreed that he lead fresh expeditions to expand the Tau Empire. There would be no peaceful retirement for Aun'shi.
- Codex: Tau (3rd Edition), pg. 53