Zerg history

The history of the zerg spans millennia.

The creation of the zerg
The proto-zerg were minature insectoids native to Zerus, a hostile ash world near the core of the Milky Way Galaxy. They were discovered by the xel'naga, an ancient extra-galactic species in the midst of perpetuating their lifecycle. Their lifecycle merged two species, one with the purity of form and the other with the purity of essence, over eons. The xel'naga previously imparted the purity of form on the protoss, and saw the proto-zerg as ideal candidates for the purityof essence. From their orbiting worldships, the xel'naga spurred the proto-zerg's evolution through proto-genetic manipulation.

The first zerg emerged from the first spawning pool. The pool split genetic information ("essence"). The proto-zerg competed within. Those that ate their counterparts evolved, and became the first zerg. The practice of evolution by consumption, and the principle of survival of the strongest, were fundamental to the zerg.

The zerg were initially parasites. They burrowed into more resilient creatures, fed on nutrient-rich spinal fluids, and finally gained control of their hosts. Zerg biochemistry evolved by assimilating genetic information from host species. The zerg used their new bodies to manipulate their environment. Only the most evolutionarily advanced species were made hosts and assimilated; lesser species were eradicated. The zerg ensured they remained the dominant species at all times. The zerg steered the evolution of assimilated species, mutating them to have armor-piercing spines, razor-sharp limbs, and ultra dense carapaces. The xel'naga were shocked by the rate of mutation; within a few generations the first assimilated species were unrecognizable. The diverse zerg strains became a unified species.

The creation of the Swarm
The zerg were united in their drive to evolve, but were still individuals. The xel'naga remembered that personal pride and ego had sundered the protoss' collective consciousness, leading to the Aeon of Strife and their estrangement from the xel'naga. To avoid similar chaos, the xel'naga created the Overmind and subordinated the zerg to its will. The Overmind served as the hub of the zerg's new hivemind, which was faciliated by a psionic link. The Swarm was created.

The xel'naga monitored the Overmind through a psionic link.

The Overmind started as a semi-sentient representation of the zerg's basic instincts and evolutionary drive, but evolved into a sentient intelligence. The Overmind created the cerebrates, giant versions of the zerg larva, to help it control the Swarm. Each cerebrate was given a specific task and control of a brood. As the Swarm expanded with new species, the cerebrates turned to s to help manage their broods.

The xel'naga Amon coveted the zerg's ability to assimilate genetic information and wished to forge it into a weapon to allow him to dominate all creation. He made major contributions to the creation of the Overmind, which allowed him to use it to further his own goals and undermine those of his species. Amon robbed the Overmind of free will by implanting an overriding directive to seek the violent destruction of the protoss. The Overmind knew it had been subverted but could not directly act to oppose it; it realized Amon's ultimate goal would destroy the zerg.

Some zerg hid and were strong-minded enough to escape subordination to the Overmind and, ultimately, Amon. They became the primal zerg, and continued to live as the zerg had before the formation of the Swarm. The primal zerg regarded the Swarm zerg as "corrupt".

To the stars
Zerg evolution eventually approached the limits of Zerus' biodiversity. The Overmind realized the Swarm had to leave the planet and seek new life to assimilate. Extending its senses into space, it detected enormous space-faring organisms and lured them to Zerus with its psionic abilities. The organisms were assimilated into the Swarm as behemoths. , and the Swarm's strains soon evolved to survive in space. This milestone was seen by the xel'naga as proof that the zerg experiment was a success.

As the Overmind extended its senses it became aware of the xel'naga worldships orbiting Zerus; its creators became the Swarm's next target. The Overmind severed the psionic link with the xel'naga, rendering its creators blind to its actions, and launched the Swarm into orbit against the worldships. Relentless zerg attacks overwhelmed the defenders within hours. Most of the xel'naga, and their knowledge, were consumed. The Overmind processed thousands of sentient to grow even more powerful, and incorporated the energies of the khaydarin crystals into itself. Its creators knowledge of evolution and proto-genetic physiology was used to improve the sentience of many strains without losing control.

Of importance to the coming interstellar journey was the xel'naga's knowledge of other species they had influenced. It was here that the Overmind learned of the general location of the Aiur, the protoss homeworld, in the galactic fringe.

The defeat of the xel'naga threw their plans for their life cycle into turmoil. Amon took the Swarm away from Zerus. Amon died long before the Swarm reached the Koprulu Sector, but his influence remained. Zerus was reclaimed by the primal zerg ;  long-lived primal zerg would see the Swarm return to Zerus during the Second Great War.

The Great War
The Swarm grew larger and stronger during its interstellar journey. Deep-space probes located new species, of which the strongest were assimilated to give rise to new strains. Despite these improvements, the Swarm still lacked a true answer to the psionic powers of the protoss. The answer came as they neared the Protoss Empire and probes discovered the terrans of the Koprulu sector. The terrans, a species with "primitive structures" and "poor biological adaptability", would have been below the Swarm's notice if not for their strong psionic potential. The Swarm set course for the Koprulu Sector while still sixty years distant.

Zerg deep-space probes on their way to the Koprulu Sector were recovered on the edge of protoss space by the Koprulu Expeditionary Force under Executor Tassadar. The probes responded quickly and naturally to the khaydarin crystal used to scan them, a clear sign of xel'naga engineering. A hostile race engineered by the xel'naga was a clear threat. The protoss stepped up patrols for signs of the Swarm, and sent Tassadar's force to the Koprulu Sector to counter the invaders. Infestation was already in progress when they arrived.

The invasion of the Koprulu Sector
The Swarm immediately infested some Fringe Worlds upon arriving in the sector. Penetrating deeper, they arrived in the Sara System. The infestation of Chau Sara was subtlely spearheaded by hive spores, followed by the bulk of the zerg force to complete the process. The Terran Confederacy sought to keep the zerg a secret from its own citizens, while using the zerg as a tool to secure its power. Confederate manipulation ultimately failed. Ironically, the anti-Confederate group the Sons of Korhal would succeed in using the zerg to destroy the Confederacy. The Swarm's invasion inexorably made its way to Tarsonis, the capital of the Confederacy. The uses of the psi-emitters by the Sons of Korhal at Mar Sara, Antiga Prime , and finally Tarsonis influenced the path of the invasion. The Koprulu Expeditionary Force followed close behind, purifying infested worlds as the terran abandoned them. The Overmind ordered the Swarm not to resist the protoss, so that it could observe the protoss in action.

At Tarsonis, the Sons of Korhal fought the protoss to allow the Swarm to complete the destruction of the Confederacy. Arcturus Mengsk, leader of the Sons of Korhal, unwittingly aided the Swarm by abandoning ghost Sarah Kerrigan, allowing the Swarm to capture her and achieve its objective. The Overmind hoped that as a human-zerg hybrid, Kerrigan would free the Swarm from Amon's malignant influence. The Swarm placed Kerrigan in a chrysalis and withdrew the bulk of its forces Char, now the Swarm's primary hive world in the Sector. In its wake the Terran Dominion rose to replace the Confederacy. There was also a growing rift between Executor Tassadar and the Conclave over the former's unwillingness to deal decisively with the zerg in order to spare terrans ; the Conclave would eventually consider the insubordinate Tassadar a more immediate threat than the zerg, hampering the Protoss Empire's response to the zerg invasion of Aiur.

The defense of Char


Inside the chrysalis, a maturating Kerrigan's psionic emanations drew terrans and protoss to Char. Kerrigan emerged from the chrysalis as the Queen of Blades and immediately joined the fighting. Kerrigan retained a strength of will and independence uncommon within the Swarm; this was to the Overmind's design. With expeditions from the Terran Dominion and Raynor's Raiders repelled, Kerrigan boarded a terran science vessel and obtained Dominion Ghost Program files to break her psionic conditioning. With her powers unfettered she detected Tassadar and the remnants of the Koprulu Expeditionary Force on Char, but not his Nerazim allies led by Prelate Zeratul. While Tassadar distracted her, Zeratul struck and permanently slew Zasz, cerebrate of the Garm Brood; the brood ran amok without its leader and was purged. The death of Zasz left the Overmind temporarily unable to communicate.

The protoss were undone by their victory. A brief psionic link formed between Zeratul and the Overmind at the moment of Zasz's death, and each read the other's mind. The Overmind learned the secret location of Aiur. The final barrier to invasion was finally removed.

Kerrigan remained on Char to continue her punitive campaign against the protoss even as the Swarm departed to invade Aiur. The protoss suffered heavy casualties but Tassadar and Zeratul survived and proved frustratingly elusive. The protoss were joined by Jim Raynor and survivors of the Raiders who could not escape Char. This unlikely alliance exploited Kerrigan's impatience to kill another. Eventually, Tassadar and Raynor were trapped on Char Aleph and Zeratul was trapped in an abandoned terran installation on the surface. They would all be rescued by Executor Artanis.

The invasion of Aiur


In the initial stage of the invasion, the Overmind made landfall on the same spot the xel'naga had first landed on Aiur. The Conclave appointed Artanis as the new executor; Artanis achieved tactical victories. From Char, Tassadar advised the protoss to cripple the invaders by killing cerebrates, but this proved ineffective as the protoss of Aiur did not wield the powers of the Void. Even as the invasion worsened, the Conclave dispatched Artanis and a fleet to Char to arrest Tassadar. To the Conclave's chagrin, Artanis returned allied with Tassadar, Zeratul, and Jim Raynor. The brief protoss civil war finally united the protoss camp; the Conclave tactfully joined a united front against the zerg. The Nerazim killed cerebrates defending the Overmind, opening the way for a strike on the Overmind. Tassadar drew upon the Void and sacrificed himself to destroy the Overmind.

It was a hollow victory. The Swarm was thrown into disarray; the zerg on Aiur rampaged and caused even more destruction. The protoss were forced to abandon the planet for Shakuras, the homeworld of the Nerazim.

The Brood War
The death of the Overmind plunged the Swarm into civil war. Daggoth led other cerebrates into merging together to form a new Overmind on Char; in the meantime they controlled most of the broods. Kerrigan and most of the remaining broods opposed them. Kerrigan sought to destroy the new Overmind, before it could mature and gain control over the entire Swarm and her, and take control of the Swarm.

Before the Brood War started, Kerrigan dispatched the Kulkulkan Brood to Bhekar Ro to secure a xel'naga temple. The attempt ended in disaster but the release of the energy creature was a sign of events in motion that would culminate a few years later.

The struggle for control
Kerrigan acquired, and manipulated, the needed allies on Shakuras. Before approaching the protoss, she remotely psionically dominated Matriarch Raszagal of the Nerazim. Kerrigan was aided by the immediate threat Daggoth's Swarm posed to Shakuras. Some of Daggoth's zerg followed the protoss evacuation of Aiur to Shakuras; the protoss killed two cerebrates nesting near the xel'naga temple. Kerrigan's offer to aid the protoss to activate the temple and secure Shakuras in return for aid against the new Overmind was accepted with Raszagal's support. Recovering Uraj took Kerrigan and the protoss to Char and into combat against Daggoth's Swarm.

Judicator Aldaris discovered Kerrigan's influence over Raszagal and led a Khalai revolt on Shakuras. Raszagal ordered Zeratul and Artanis to put down the revolt and kill Aldaris. However, instead the prelate and executor offered reconciliation in exchange for Aldaris' renewed cooperation. The judicator refused and was killed by Kerrigan before he could reveal her deception. The protoss were outraged by Kerrigan's interference; the alliance was broken but she left the planet having ensured the deaths of two enemy cerebrates. The protoss subsequently activated the Shakuras temple and scoured the zerg from the planet.

The zerg civil war was complicated by the arrival of the United Earth Directorate Expeditionary Fleet with orders to take control of the Overmind and take control of the Koprulu Sector. Even as the Terran Dominion fell to the UED, Kerrigan was preparing to remove the new invaders. She used Jim Raynor's conflicted feelings for her to gain the cooperation of Raynor's Raiders; in turn, Raynor secured aid from the protoss of Shakuras for her. The Raiders and Fenix helped Emperor Arcturus Mengsk evade capture by the UED Like with her prior protoss allies, she used the threat of a greater enemy to gain cooperation.

For a time, Kerrigan was aided by an agent in the UED. Samir Duran was an shapeshifter secretly allied with Amon, but assumed constructed identities to enter the confidence of Kerrigan and UED. Duran joined the UED disguised as a terran anti-Dominion rebel, actually working for Kerrigan to sabotage the UED. Duran played a key role in Mengsk's escape. However, he was exposed in a failed attempt to destroy the original psi disrupter on Braxis; before fleeing the UED he mortally wounding UED Vice-Admiral Alexei Stukov. After that, Duran was known by the infested terran layer of his disguise.

The intact psi disrupter proved vital to the UED. It disrupted zerg control throughout the sector, allowing the UED to attack Char and capture the Overmind. This gave the UED control over several broods. Their tenuous hold over the Overmind limited the distance that broods could be controlled through remote means alone.

Kerrigan ascendent


The psi disrupter gave the UED a significant advantage. It granted it control over most of the zerg broods, disrupted Kerrigan's control over her broods, and prevented her from controlling broods not yet claimed by either side. Kerrigan had planned for this when she had Mengsk rescued. Mengsk agreed to loan psi-emitters in exchange for her help in taking Korhal back from the UED and returning it to the Terran Dominion. Kerrigan used the psi emitters to gain control of feral zerg on Braxis, which she used to destroy the psi disrupter. After a build-up the allies moved on Korhal. The defenses, reinforced by UED's zerg, were broken. Korhal was restored to the Dominion, and the UED lost their primary staging point in the Sector. With Char the only remaining UED stronghold, Kerrigan no longer needed her allies. Before leaving Korhal, she betrayed her allies and struck heavy blows against both the Dominion and protoss, killing Dominion General Edmund Duke and Fenix.

Two days later, the UED used zerg to attack Kerrigan on Tarsonis, but the attack failed due to brittle control of the Overmind.

Kerrigan and Duran traveled to Shakuras to take Matriarch Raszagal hostage in order to coerce Zeratul and the Nerazim into killing the second Overmind on Char. The Matriarch was sheltered within the Nerazim capital of Talematros, which was fortified by the Sargas and Venatir Tribes. However, the zerg were able to breach Talematro's defenses and destroy the city. Kerrigan traveled to Char with her hostage, and was followed by Zeratul who demanded her release. Kerrigan promised to return Raszagal if Zeratul and the Nerazim helped her kill the Overmind. Although Zeratul doubted her trustworthiness, Raszagal appeared and asked him to follow through which he reluctantly did. A huge battle erupted between the UED and Kerrigan's zerg, with the Nerazim aiding Kerrigan's forces. The UED's defense was supplemented by its slave broods, but eventually, they were overwhelmed by Kerrigan's zerg.

Eventually, Zeratul personally killed the Overmind. He then demanded Kerrigan to release Raszagal, but the Matriarch refused. He realized that Raszagal was enthralled to Kerrigan and he escaped with her via arbiter recall. Six hours later, Samir Duran reported to Kerrigan that with the Overmind and its supporting cerebrates dead, all of the zerg in the Koprulu Sector had reverted to her direct control. However, Zeratul had collected with a number of protoss on the planet surface, and was preparing to initiate dimensional recall to Shakuras. He did not have enough time to escape, as the zerg were quick to block the protoss from escaping with the matriarch. Realizing that Raszagal was beyond redemption, Zeratul killed her (to the surprise of Kerrigan) rather than allow her continued enslavement. Afterwards, Duran abandoned the Swarm and his infested terran guise to return to his true work, the creation of the hybrid. Kerrigan's assimilation into the Swarm had been a boon to this effort.

The Dominion, protoss, and UED struck at Char with unexpected alacrity before the zerg could consolidate. The zerg held and the all three assailants were forced to retreat. The Swarm were secure, and Kerrigan emerged as the Sector's dominant power. After the destruction of the fleeing UED fleet by the Swarm, the belligerents were finally exhausted and an uneasy peace fell over the Sector. The zerg retained worlds they had infested.

The Swarm recovers
Intermittent fighting continued between the end of the Brood War and the start of the Second Great War even as the powers withdrew to recover. The Swarm refrained from overt hostilities against the terrans and protoss, and engaged only in occassional skirmishes. The Swarm destroyed all expeditions to its worlds. UNN and other terran news services that covered general threats did not report on the zerg during this time, and observers could only speculate on the Swarm's restraint.

The Swarm sought out new worlds and species to infest and used spies to collect xel'naga artifacts. In 2502, the Swarm were estimated to have infested over a hundred worlds. In 2503, the Swarm attempted to capture archeologist Jake Ramsey while he carried the consciousness of the protoss preserver Zamara. Ramsey and Zamara also interested the other powers and the resulting clash allowed them to escaped the Swarm.

New strains were created. The baneling was bred from the attack on the terran colony on Sorona. In accordance to Kerrigan's vision for the Swarm, the cerebrates were destroyed and replaced with broodmothers. The broodmothers were made to evolve their broods and respect only strengh; these qualities exacerbated the fragmentation of the Swarm during the Second Great War.

Other zerg
The New Swarm was created by cerebrate Kaloth as an experiment in human-zerg hybrid leaders. Kaloth resurrected and infested Alexei Stukov, who led the New Swarm as a conglomerate of zerg and renegade terrans on Braxis. The New Swarm did not last long. It dissolved when Stukov was temporarily deinfested by a protoss nanite serum delivered by Jim Raynor. Stukov was given to the so they could study the nanites. When the nanites failed and his infestation returned he was experimented upon. He was imprisoned at the Terran Dominion's Skygeirr Station, where Emil Narud (possibly Samir Duran from Brood War), a servant of Amon working to resurrect his master, created the hybrid.

The zerg on Aiur remained part of the Swarm but they escaped strong control. From the chaos of the first Overmind's death, these zerg had regained some intelligence, but were still less vicious and focused and they did not reproduce. This hampered Swarm operations on Aiur.

The Prophecy
"Do you hear them Zeratul? Whispering from the stars? The galaxy will burn with their coming."

- Kerrigan describes the coming threat.

At the end of the, Kerrigan already had forebodings for the future. Narud would later claim Amon "told" her these portants of doom. In the following years, Kerrigan learned something of Duran's activities. What she learned of Amon's coming catalysm caused her to lose all hope for the future. Nonetheless, she resolved to fight it and sought out a xel'naga on Ulaan for further information. As Kerrigan expected, Zeratul arrived searching for the same prophecy. The Nerazim prelate found the prophecy and took it away before Kerrigan could see it. Zeratul learned through the prophecy that Kerrigan was needed to stop Amon ; Zeratul would assist her in the coming conflict.

In addition to the prophecy, Kerrigan wished to acquire components for a xel'naga device which were scattered across the Sector. In 2503 the Swarm was nearly recovered from the Brood War. The next time the Swarm invaded the Sector in strength, one of its tasks would be to search for and retrieve the components. On the eve of the Second Great War, the Swarm had made good past damages; Char alone was estimated to have over ten billion zerg in 150 primary and 1029 tertiary hive clusters.

The Second Great War
"I know that it has been years since we've seen any zerg activity in terran space. But I hope you're prepared for the next encounter. The zerg are coming. The zerg are nature in all her fury."

- Maren Ayers warns her Dominion interrogator


 * Main article: Second Great War



Race for the artifact
Kerrigan had many reasons to unleash the Swarm on the Sector and starting the war. For the Swarm, there was the search for the xel'naga device and the drive to evolve. For herself, there was the desire for action and revenge against Emperor Arcturus Mengsk of the Terran Dominion The Swarm offensive achieved strategic surprise.

The zerg advanced on all fronts. The Dominion Armed Forces suffered heavy casualties to slow the advance. A major contributing factor to the Dominion survival was that the Swarm was not immediately concerned with systematically destroying it.

While the Swarm conquered worlds, it had no success with the xel'naga device. In competition with the Swarm, Raynor's Raiders recovered all the components and delivered them to Prince Valerian Mengsk of the Terran Dominion. With the components in terran hands, the Swarm slowed its offensive in terran space.

Fall of the Queen

 * Main article: Battle of Char (Dangerous Game)

Prince Valerian planned to use the xel'naga device to deinfest Kerrigan. A joint Terran Dominion and Raynor's Raiders force attacked Char to deliver the device in range of Kerrigan.

Though most if the Swarm was off-world, the remainder was sufficient to win through attrition given time. Kerrigan recalled the closest broods invading the Dominion as reinforcement, although they would ultimately not arrive in time. The invasion worked to Kerrigan's advantage; the terrans had literally delivered the complete xel'naga device to her.

The terrans compensated for their lack of time and numbers with operational surprise and audacity. The device deinfested and removed the last vestiges of Amon's influence from Kerrigan. She was saved from would-be-assassin Tychus Findlay, working for Emperor Mengsk, by Jim Raynor. Raynor was motivated by his old feelings for her and by Zeratul; after deciphering the prophecy on Ulaan, Zeratul had implored Raynor to ensure Kerrigan's survival.

The psionic energy released by Kerrigan during deinfestation may have been collected by hybrid and used to complete the resurrection of Amon.

The removal of the Queen of Blades marked the start of another period of disunity within the Swarm. Broods scattered over the Sector became independent under their respective broodmothers. The fragmentation aided the Terran Dominion's zerg-extermination campaign on Char. Zagara, the broodmother, on Char, fought an unsuccessful campaign against them.

The Swarm resurgent
A deinfested Kerrigan was taken to Research Station EB-103 in the Umojan Protectorate where she rekindled her personal relationship with Jim Raynor. A Dominion attack forced them to flee and they were separated. Kerrigan escaped but Raynor was captured and reportedly executed. This enflamed her desire for revenge against Mengsk. To pursue this she would wield the Swarm.

Kerrigan journeyed to a leviathan to resume control of the Swarm. The Swarm's fragmentation made an immediate assault on Korhal impossible. Kerrigan was reunited with broodmother Zagara during the reconquest of Char from the Dominion. Kerrigan had Abathur enhance Zagara's intellect, ultimately making the broodmother an adaquete replacement leader for the Swarm. This violated a long-standing imperative that prevented competition over the Swarm's leadership; Kerrigan found this acceptable.

Kerrigan's transformation back into a human-zerg hybrid was pivotal. Driven by the from Ulaan, Zeratul guided her to Zerus to be transformed using the primal zerg-human hybrid; Kerrigan was motivated only by revenge against Mengsk. Kerrigan emerged from the first spawning pool more powerful than her old hybrid form and free from Amon's influence. Furthermore, whereas before she could merely "hear" and "control" the Swarm, now she could "feel" and "be" it. Her power increased by defeating and absorbing the essences of the other primal pack leaders. The Swarm returned to the Koprulu Sector with Dehaka and other primals.

The Swarm found new purpose at Skygeirr Station, home of the Dominion's hybrid production program led by Emil Narud. The Swarm found the secret installation with the aid of infested Alexei Stukov and destroyed it. Kerrigan killed Narud and learned of Amon's resurrection. Kerrigan recognized the extreme danger posed by Amon; the Swarm would seek out and fight Amon, although she regarded this as a hopeless battle.

The broodmothers gradually returned to the Swarm as Kerrigan's psionic powers and list of victories grew; the rejoining broods were sent to crippled the Dominion's war effort.

The last obstacle to the invasion of Korhal was Jim Raynor. Kerrigan learned Raynor was alive and being held hostage by the Dominion; he would be executed if the Swarm moved on Korhal. With the aid of Raynor's Raiders, Kerrigan found and rescued Raynor from the prison ship Moros.

The Swarm converged on Korhal. Prince Valerian Mengsk agreed to Kerrigan's bid to kill Emperor Arcturus Mengsk. In turn, she endored Valerian as his father's successor and agreed to avoid unnecessary civilian casualties. Dominion fleets deployed outside the system responded quickly and were engaged by the Swarm's contravallation. The Swarm braved ferocious anti-orbital fire to establish a planethold outside of Augustgrad. The city was protected by the Psi Destroyer, which killed zerg linked to the hivemind; the primal zerg, hitherto unknown to the Dominion and unlinked to the hivemind, were immune to the Destroyer and spearheaded the assault that destroyed it. The Swarm was joined by Hyperion and Jim Raynor as it surged into the city and broke into the Korhal Palace. Kerrigan confronted Emperor Mengsk inside. Raynor's intervention prevented the emperor from killing her using the xel'naga device, and allowed Kerrigan to kill Mengsk.

The Swarm withdrew from Korhal to wage war against Amon.