The War of the Aiur System

"Aiur is lost... Shakuras is our only hope for survival...

Are you mad, Artanis? Are we to consort with the Fallen Ones?

I am far from madness, Khortanul. The Great Fleet may stem the Keltakens for now, but not forever. Their numbers are too great. We must go. NOW!"

The War of the Aiur System is the 20 day long war between the Keltaken Imperium and the Eldari Empire. In this short time, there were high-reaching effects.

Origins of the conflict
It was the middle of the Second Intergalactic War, and the Eldari Empire was one of the few allies the Colonies had then. The Eldari generally are not interested in the squabbles of other races, but the far-sighted Eldari were concerned that the Keltakens will force them to submission once they come near. As a countermeasure, the Conclave struck a secret alliance with the Colonies. The Empire mainly lent their psionic powers to the FCM, along with cybernetic strikes against Keltaken computers. It took the Keltakens several years to finally uncover the culprits of these attacks, as the Eldari used ancient, forbidden technology that used to be banned by the Conclave.

In their wrath, the Keltakens descended on the Aiur System, taking no heed to the fact that many of the populace are not even aware of their nation's involvement in the Intergalactic War. Still they came, and they first struck at the outlying systems under Eldari control. These systems were barely even able to put up a fight, as the Eldari population were mostly concentrated in and around Aiur. The Great Fleet was quick to respond, but the sheer numbers of the Keltakens forced them to withdraw. After that, the Eldari began utilizing every bit of forbidden technology, such as reactivating the banned Colossi, and recomissioning many old vessels that were still strong in weaponry and armor. So, the Great Fleet and the Keltakens fought to a standstill in the edge of the Aiur System.

Then Tassadar returned.

Executor Tassadar wa previously sent by the Conclave to purge worlds infested by a xenomorph species called the Zuraji. He had just accomplished his mission, and expected a hero's welcome but instead was branded a traitor, as he had consorted with the heretics, the Shadow Templar. While the Keltakens and the Great Fleet battled endlessly in the system's edge, Tassadar was held in trial by the Conclave, but he was rescued from the court by cloaked Shadow Templar, who then lead him to the Ganthris, his personal ship. He then called on his forces to assist the newly arrived Shadow Templar forces. But as time passed, the Great Fleet slowly lost ground against the numerically superior Keltakens. It was around this time the young Praetor, Artanis(for the Eldari, 200 years old is still young), suggested that the Conclave evacuate the population to Shakuras via the last functioning Warp Gate on Aiur. The dogmatic Conclave refused, believing they can still repel the Keltaken attack. But they were proved wrong, as the Keltaken ground forces landed on Aiur itself, and started to destroy its cities. The stubborn Conclave still refused to go to Shakuras, as Shakuras was the adopted homeworld of the Shadow Templar, and they expected the would be evacuees to be slaughtered there because of old grudges. Needless to say, billions died in a matter of days, and the Conclave itself was finally destroyed in the 18th day. Then, Tassadar led the survivors into the Warp Gate. The survivors were assured by Zeratul that they will have asylum, and not death. However, as the Keltakens closed in, it became necessary to close the gate, and the Eldari shut it off. This act stranded at least 100,000 Eldari. These survivors banded together in the vast underground caverns that were forbidden by the Conclave ages ago.

They survived until the Reclamation of Aiur.