Primal Zerg

The primal zerg were a zerg subspecies from the planet Zerus who retained the physical and psychological traits of the original zerg, those who had avoided incorporation into the Zerg Swarm. When Amon created the Overmind to bind the species to his will, a number of zerg on Zerus escaped that control. They remained on their homeworld and continued to hunt, prosper, and evolve as the Swarm, unaware of their existence, departed to wage war across the stars. (StarCraft II: Heart of the Swarm)

Ancient history#

The zerg emerged from the first spawning pool on Zerus, feeding on one another's essence and gaining strength, a practice they carried beyond the pool as they assimilated the planet's other lifeforms. When Amon uplifted the zerg he intended to use them for his own ends, but their independent nature forced him to create a hive mind to direct the species and make it controllable. The result was the Overmind, under whose control most of the zerg fell, an event witnessed by Zurvan. (StarCraft II: Heart of the Swarm)

After Amon unleashed the Swarm upon the other xel'naga, the zerg under the Overmind left Zerus and became known as the Swarm. At that point the species split along two paths. A number of zerg had escaped the Overmind's control; they remained on Zerus and became known as the primal zerg, continuing to prosper, hunt, and evolve while the Swarm passed into the wider galaxy without knowing they were there. (StarCraft II: Heart of the Swarm)

The Second Great War#

By the time of the Second Great War the primal zerg had existed for at least millennia. During the conflict they finally encountered their Swarm counterparts. Sarah Kerrigan, made human again by the Keystone, sought a new means of restoring and increasing her power, and aboard her leviathan she met the Dark Prelate Zeratul, who revealed to her the existence of Zerus and of the primal zerg whose nature could transform her once more. (StarCraft II: Heart of the Swarm)

On arriving at Zerus, Kerrigan awakened Zurvan and was attacked by the primals, who meant to kill the corrupted Swarm zerg. She achieved her primal form, defeated the primal leaders, and their packs joined the Swarm. She departed Zerus with Dehaka, his pack, and the other primal zerg who chose to follow in the hope of acquiring new essences. Dominion field reports later suggested the primals kept a degree of autonomy even within the Swarm. During Kerrigan's attack on Korhal, the Terran Dominion activated the Psi Destroyer, a superweapon that killed zerg through their hive mind; because the primal zerg were sentient individuals with no hive mind, they were immune, and Kerrigan dispatched Dehaka and his pack to weaken the enemy until the Destroyer was destroyed. The primals then took part in Kerrigan's final assault on Augustgrad, and after she killed Arcturus Mengsk they left Korhal with the rest of the Swarm to fight Amon. (StarCraft II: Heart of the Swarm; StarCraft Field Manual)

The End War#

The co-op missions carry the primals into the End War. There, Dehaka leads his pack against the forces of Amon, joined by three newer pack leaders, Glevig, Murvar and Dakrun, whom he has brought into his own pack. (StarCraft II co-op missions)

Physiology#

The primal zerg bore the genome of the zerg race as it had been before the Overmind established control. Where the strains of the Swarm tended toward an insect-like appearance, the primal zerg resembled reptiles, especially dinosaurs, and in some respects mammals. They did not age, and could be killed only by being consumed by another predator, which meant the greatest hunters among them were ancient. Like the Swarm, the primal zerg could take essence from their foes by consuming their flesh and through it their genetic material, and they existed in a constant state of evolution, incorporating beneficial traits from their victims. Such traits could become manifest in a short time, from seconds to hours or a few days, and through this the primal zerg were able to mimic numerous Swarm strains while keeping their own physiological markers. (StarCraft II: Heart of the Swarm; StarCraft Field Manual)

Psychology and society#

The primal zerg were individuals, and many despised the Swarm zerg as corrupted by the inter-entity psionic connection of the hive mind, a fate Zurvan described as terrible. Lacking that connection, the primal zerg were immune to psionic measures that would otherwise cripple Swarm zerg, including control by the Queen of Blades, though they remained vulnerable to sigma radiation. (StarCraft II: Heart of the Swarm; StarCraft Field Manual)

Primal society was hierarchical, organized into packs led by pack leaders who were the strongest among their number. Its culture was Darwinian, founded on survival of the fittest: loyalty was commanded by the ability to survive challenges from underlings, and ascension came through consuming weaker superiors when the opportunity arose. (StarCraft II: Heart of the Swarm)

Pack leaders#

Pack leaders were the most powerful primal zerg. During the Second Great War, Kerrigan killed the pack leaders Brakk, Kraith, Slivan the Eternal Mother, Yagdra, and Zurvan the Ancient One, and their packs were integrated into the Swarm. Kerrigan herself became a pack leader by virtue of her position, biologically a terran and primal zerg hybrid, with Dehaka allied to her. In the co-op missions, the newer leaders Dakrun, Glevig and Murvar fight within Dehaka's pack against Amon. (StarCraft II: Heart of the Swarm; StarCraft II co-op missions)