The fleet was sent to Sha'draig to investigate an orbital perimeter outpost's silence. But by the time the fleet arrived in 990.M41, Sha'draig was already under siege. Valroth's fleet broke through the Tyranid blockade surrounding the planet long enough to deliver reinforcements to the surface, where Shas'el Vorcah directed a desperate defence. In 901.M41 Supreme Admiral Kor'O'Vanan withdrew the fleet and all surviving forces from the planet as he deemed the situation irretrievable. Vorcah choose to stay behind and eventually drove Gorgon from the planet, but not before it had been almost completely consumed by Ripper swarms.
As Gorgon made its way further through the Tau Empire towards Kel'shan, Volroth's fleet was heavily retrofitted at the Kel'shan shipyards to counter Gorgon's evolved immunities to Tau weaponry. But his fleet was then diverted to engage an Imperial fleet that emerged from the Warp and immediately besieged Kel'shan, unaware that their warp journey had taken one hundred and fifty years and the Damocles Crusade they were dispatched to fight in had already come to an end. In 785902.M41 Gorgon descended upon Kel'shan and joined the already underway battle between the Tau and the Imperium. Now faced with a common enemy, Valroth agreed to a truce with Castellan Crask of the Cadian XVIIIth and together their fleets turned on Gorgon and destroyed close to all of its bio-ships. Gorgon, unique for its ability to rapidly evolve its bioforms, was unable to adapt quickly enough to the disparate nature of the Tau and Imperial Guard forces combined, and at the Battle of Worldspine Ridge the forces of Gorgon were finally defeated. Valroth's truce with the Imperium also ended shortly after.