The following section contains information from StarCraft: Insurrection.
When the Cerebrate was created, Brontes IV was in the midst of conflict: a conflict that the Overmind intended for the zerg to win. Shortly after its creation, the Cerebrate was tasked with capturing protoss Judicator Syndrea while fellow Cerebrate Nargil engaged the protoss in orbit above the planet. In this the Cerebrate was successful, later being charged with preparing for the arrival of the Fenris Brood, along with destroying the terran forces in the area and that of the rogue Carpenter's Brood, which the Overmind realised to be the former Incubus Brood. The Cerebrate then crushed the remainder of Syndrea's forces, who at attempted to regroup with the retreating fleets of Executor Andraxxus .
The Overmind hoped to turn the terrans and the forces of Executor Andraxxus against each other, but they instead formed an alliance. The Cerebrate was thus forced to rescue a Fenris hive cluster from the combined forces and then crush them. Victory came to the Cerebrate when its forces descended upon the remnants of the 7th Fleet and the New Dresdin Outlaws, eliminating them. Shortly afterwards, it eradicated Carpenter's Brood and slew Atticus Carpenter, securing Brontes IV for the zerg.