Libria III: Cartasia plains swept clean by Sky Lords

The next move by the alliance was to attack Crusade positions in the Cartal mountains to the west of the Cartasian plains themselves in an effort to widen the narrow corridor which kept alliance forces in the city of Cartal in ground communication with the rest of the alliance.

Since the city had been taken, Cartal itself had come under seige, but the alliance had kept open a strip of land, some fifty miles wide at its narrowest, leading to the Riker sea and the lands of Vardashi and Cerra. Now Skyfall was tasked with widening this corridor, and if possible rolling back the arc of crusade forces to the west and north of the city. If successful the siege of Cartal would be lifted and the remaining Crusade forces in Cartasia would be isolated from osne another.

Skyfall's attack took the defenders by surprise initially. The tau attacked in moderate strength, initiating a predictable and in fact hoped for counter attack by the Crusade's mobile reserve, this time in the form of the Sky Lords. this counter attack was then ambushed by Skyfall's main force, which had been carefully concealed by advanced tau technology and simple ruses such as camo netting.

The Sky Lords proved to be a difficult opponent for the tau however. The astartes force had learnt from their previous encounter, and despite the ambush, little damage was inflicted on the Crusade force. In reply, grav cannons were employed successfully against Riptide battle suits, and the space marines' land raiders held off enough tau firepower to deliver the elite terminator squadrons into battle with the tau command units.

This time despite their superior technology, the faith and brute strength of the imperium's warriors proved the more enduring, and the tau command, leading from the front once again, was smashed by the Sky Lords' chaplain and assault terminators. the remaining crisis suits were annihilated by the astartes grav cannons, while the Sky Lords sent their tactical squads after the "softer" tau forces.

Soon the tau attack was in all kinds of trouble, and the Sky Lords' counter attack became a full scale offensive. Sensing a victory, Vorushko threw in her reserve forces, cutting the alliance corridor and sweeping across the Cartasian plains reaching the Riker Sea on 0804.015M42. Cartal was now fully cut off and Skyfall was left wondering what went wrong. Only days after the battle was it revealed that his Broadside Battlesuits had in error been deployed facing the Crusade forces in Aegon, while Skyfall expected them to take part in the attack on the Cartal Mountains. this mistake may have contributed to the defeat, and Skyfall was forced to undertake a review of the army's communication procedures. On the ground, the crusade had won a badly needed victory, but strategically their position remained weak.