Aun'ui Yor'i
Aun'ui Yor'i is an Ethereal of the Tau Empire.[1a]
History
Yor'i served as the most senior Ethereal leading the Cao Quo war effort, but at some point was the victim of an assassination attempt by an Imperial Callidus Assassin working with the Raptors Space Marine Chapter. This false Yor'i then began spreading discontent amongst the various factors on Cao Quo, using the renegade Syra group to commit massacres against Gue'vesa while covertly aiding the Raptors Sergeant Artamax in the insurgency. The ultimate Imperial plan was to undermine the entire Greater Good and spread disharmony throughout the Tau Empire. However the real Yor'i managed to survive the initial assassination attempt due to the intervention of local Humans on Cao Quo, who saved him and slowly nursed him back to health.[1a]
However, the Assassin impersonating Yor'i's plan began to be investigated by the Ethereal Aun'ui Kir'qath, which led to multiple attempts by Yor'i and Artamax to eliminate her.[1b] The Assassin Yor'i was eventually exposed by the very Elemental Council they organised to recover Kir'qath, forcing the assassin to reveal themselves and kill the Water Caste emissary Orr as she sets free the captive Artamax aboard a Tau orbital base.[1b] In the subsequent battle against Swordlight, Ke, and Ghodh manage to wound the Assassin as the base crashes. The assassin Yor'i miraculously survives, before being discovered and killed by Ghodh, who takes and presumably consumes her heart.[1a]
Meanwhile, the real Yor'i has managed to return to the Tau on Cao Quo. Grateful to the Humans that saved him and realizing that the Greater Good will be undermined by Artamax's plan, Yor'i decides to withdraw from the planet to prevent a bloody retribution from the Tau over the harm that has befallen multiple Ethereals. He grants Cao Quo de facto independence, though its future is unclear and it may face future Tau and Imperial invasions.[1a]