The Tau’s first encountered Petrollix during the Third Sphere Expansion. When the Cru’stea sept’s water caste landed to start diplomatic processes with the natives, they discovered Petrollix already contained a healthy settlement from the Imperium of Man.
The Imperium had found that Petrollix’s sprawling dried oceans contained a large source of fuel and energy resources. Imperial mining and refinery colonies tasked with satisfying Imperium’s thirsty consumption were set up in these dried ocean beds which began the process of pumping the world dry of its abundant resource. They soon set up the Master Refractor, an enormous energy generator which harnessed the energy from the planets core.
Over the next few years after the start of the water caste’s diplomatic conquest, the men of the Imperium on Petrollix became convinced that they have been abused and forgotten. The ethereal leading the water caste, Aun’qi, and his message struck to the heart of many of the men. The Tau’s mission of the Greater Good saw many men pledge their support to the Tau, but those who did not subscribe these ideals soon presented an armed resistance. The Cru’stea’s fire caste deployed to the surface and quickly squashed the resistance. With the resistance quelled, Aun’qi claimed Petrollix for the Tau Empire, renaming it Path’tal.
Now the Cru’stea sept has a firm grasp on Path’tal and set up a stronghold here. The Earth caste with the assimilated humans, known as gue’vesa, began utilizing the existing extraction and refinery facilities for the Greater Good of the Tau Empire. The rich resources were a boon to the upstart Empire, and the Imperium of Man could not stand for it.
The Imperium soon returned in force to attempt to take Path’tal back from the xenos. The Cru’stea’s air caste intercepted the Imperium’s retaliation force before they could reach the planet’s surface and won major victories which cause a heavy amount of debris to fall to the planet. Those soldier lucky enough to get there boots on the ground were met with fierce resistance led by commander O’tria. A Tau victory was immanent.
In a final desperate act, the Imperium turned their focus towards the Master Refractor. Their hopes were to destroy it and destabilize the planets core. If it didn’t out right destroy Path’tal, it would knock the planet out of alignment and the resulting radiation would make it uninhabitable. The Imperium made a fierce attempt at the Master Refractor, combining all of its forces into a single pointed force to spear through the Cru’stea defenses. O’tria split her forces into 3 units, one taking the head of the spear while the others flanked in a pincer maneuver and crushed the Imperium’s last hopes and driving them off Path’tal for the time being.