- The Overmind addresses the newly created Cerebrate.(src)
This cerebrate was the player character of Episode II, entrusted to watch over Sarah Kerrigan after her implantation inside a chrysalis. It was slain by Tassadar on Char during the zerg invasion of Aiur. The young cerebrate had yet to assert an individual personality, or merit a name through extended service.
- The Overmind gives the Cerebrate its orders.(src)
The zerg captured a psionically-gifted terran, Sarah Kerrigan, during the fall of Tarsonis. The terran required a period of incubation in a chrysalis before she could become a powerful agent for the Swarm. The Overmind created the cerebrate on Tarsonis specifically to guard the chrysalis during this vulnerable stage.
The cerebrate established a small hive cluster on Tarsonis. It was supervised by Daggoth, a senior cerebrate and leader of the Tiamat Brood, and Zasz, leader of the Garm Brood. On Zasz's order the cerebrate destroyed a nearby group of terrans to ensure the safety of the chrysalis and hive cluster.
- The Overmind(src)
In a short time the cerebrate grew strong enough to endure warp travel, and the Overmind decreed the Swarm relocate to Char. The cerebrate and chrysalis were escorted through protoss forces at New Gettysburg; Tiamat Brood Hunter Killers formed part of the escort. Once safely through the cerebrate experienced its first warp jump and journeyed to Char.
Though vulnerable, Kerrigan was not dormant. Her psionic emanations drew terrans and protoss alike to Char. The Terran Dominion's Alpha Squadron, led by General Edmund Duke, were the first to assault the chrysalis' resting place; the cerebrate counter-attacked and forced the terrans to abandon their landing zones and retreat. The cerebrate relocated the chrysalis while Daggoth dealt with the remaining enemy forces.
Alpha Squadron was followed by Raynor's Raiders. The attack came at a critical time as Kerrigan would soon emerge from the chrysalis. The cerebrate held off the new interlopers until Kerrigan emerged. With its new agent unleashed the Overmind ordered the zerg to press the attack. The Raiders were routed; Kerrigan allowed Jim Raynor and a few survivors to flee.
The cerebrate continued to assist Kerrigan after her rebirth. Its minions assisted her during the raid on the science vessel Amerigo, and when she hot-headedly answered Executor Tassadar's challenge. The High Templar's attack was defeated but it served its purpose. The Dark Templar Zeratul assassinated Zasz while attention was focused on Tassadar. The cerebrate was forced to eradicate the leaderless and rampaging Garm Brood threatening the primary hive cluster.
Although unintended, Zeratul effectively traded the location of Aiur for the death of Zasz and his brood. An exultant Overmind emerged from the shock caused from the permanent loss of a cerebrate. It ordered the majority of the Swarm to invade the protoss homeworld. Kerrigan and the cerebrate remained on Char to hunt the remaining protoss. Even so, the cerebrate remotely presided over several pivotal battles on Aiur.
Blade in the Darkness
Tracking the protoss was not as easy as first anticipated as their quarry continued to evade them. Kerrigan led with oft-counterproductive impatience. In the end this impatience was the cerebrate's undoing. History repeated itself when Kerrigan led her brood into a trap laid by Tassadar, Zeratul, and Raynor. While Raynor and Zeratul fought Kerrigan and the brood, Tassadar infiltrated the cerebrate's lair and killed it.