High psionic power
Combinations of various dual species possessing purity of form and essence
The xel'naga are a psionically-attuned, ancient, cosmic race. Described as "the most powerful species the universe has ever known,", vague references exist of the xel'naga having visited countless worlds and uplifting life throughout the cosmos to a higher state of being. Their most notable involvement was with the protoss and zerg, whom the xel'naga endowed with perfection in "form" and "essence", respectively. When the incredibly long-lived xel'naga reached their end, these two species were to naturally merge and give rise to a perfect life form -- becoming the next iteration of xel'naga. Ominously, the xel'naga's re-emergence in the universe was severely jeopardized when the zerg turned on them at the behest of one of their own.
The xel'naga have been referred to as "Wanderers from Afar," but it has also been described as being their true name. The protoss referred to the xel'naga as the "Ihan-rii", the "Great Teachers", the "Makers", and the "Guardians", during the Aeon of Strife, and prior to it, worshipped them as gods. Some protoss still refer to them as such.
The xel'naga were incredibly long-lived even by protoss standards, but not immortal; eventually their species would come to an end. In the interest of survival they planned to create new xel'naga by uplifting two species. A pair of qualities was required and these were defined by the xel'naga as the purity of essence and the purity of form, and each uplifted species would be targeted for one of them. Over an extraordinarily long period of time, the two species would naturally come together and merge.
The xel'naga life cycle had manifested many times.
Arrival in the Milky WayEdit
The xel'naga arrived in the Milky Way galaxy from outside. Tens of millions of years before the Great War, the xel'naga seeded thousands of new species in the worlds within their domain. They experimented on and uplifted suitable candidate species. For millennia they met only with failure.
The following section contains timeline information which isn't necessarily in chronological order.
During their journeys, they learned of the Voice in the Darkness, a Void-based entity which consumed entire civilizations. The xel'naga, who cherished life, imprisoned it with an Argus crystal beneath a barren world at KL-2.
The xel'naga found or created a powerful relic, the Argus Stone, which they valued over other artifacts, but left it on the world of Aridas. The zerg believe it had been used to create entire races.
On the galactic fringe the xel'naga returned to Aiur, one of their engineered worlds. They discovered there a race of tribal hunters with a psionically-enhanced communal society. When coupled with excellent physical attributes the xel'naga recognized the natives as superior candidates for the purity of form and, impatient with the slow pace of their evolution, began uplifting them, using devices such as a giant crystal beneath Aiur. They even used devices such as the Kassia crystal to enhance their rate of reproduction. The natives were the first experiments to progress beyond a feral stage. In recognition of this the xel'naga named their new scions protoss, meaning first born.
Initially the xel'naga kept their presence and assistance secret, but once the protoss were deemed ready the xel'naga revealed themselves openly. A "protoss" temple was built where the xel'naga first landed on Aiur. The xel'naga also constructed giant artificial caverns or a city beneath Aiur, and hid khaydarin crystals around the planet.
The protoss were united by their fascination with these new "gods." They called their new benefactors the Ihan-rii, the "Great Teachers", the "Makers", and the "Guardians". The Shelak Tribe grew closest to the xel'naga. The protoss progressed rapidly technologically but rifts began appearing between the tribes concerning their perception of the xel'naga. At first, the xel'naga were intrigued by this ideological development, and conducted an experiment to see what effects the diverging tribes might have on khaydarin crystals. They created twin crystals, the Khalis and Uraj, from a monolithic crystal and gifted them to the Sargas and Akilae Tribe respectively. The crystals' powers and appearance diverged with their tribes.
The ideological split proved more severe than the xel'naga realized. The protoss fractured along tribal lines and caused the psionic communal link to break. The xel'naga were disappointed but realized having pushed the protoss too far too fast they were responsible. The xel'naga decided to leave this creation. The xel'naga were already done with the protoss, and needed to work on a new species.
Hundreds of xel'naga were killed in attacks by angered and confused protoss. While their fleet withdrew, the xel'naga left behind many artifacts such as the khaydarin crystals. At least one ship was also left behind.
The protoss degenerated into the Aeon of Strife. However the xel'naga's mark on the protoss endured, and their abandoned artifacts later aided the protoss to re-emerge from the chaos as a galactic power.
While the protoss were regressing they had all the essential qualities of the purity of form. The xel'naga set off to find a suitable companion embodying the purity of essence. They found a suitable candidate on the coreward world of Zerus. There the xel'naga began genetically manipulating the zerg, an insignificant life form of miniature insectoids. The initial experiment was a resounding success. The parasitic zerg quickly became the dominant lifeform on the planet, with other creatures being assimilated and evolved or simply eliminated. The xel'naga were shocked to discover how quickly assimilated species could be changed beyond recognition within the space of a few generations.
In the view of the xel'naga, the protoss had failed due to the independence of the individual and conflicts of ego that arose from that. To avoid the same with the zerg, the xel'naga consolidated control of the collective zerg sentience into a single entity, the Overmind. The xel'naga used a psionic link with the Overmind to monitor the zerg, but the xel'naga kept the link secret as to not reveal their presence.
The Overmind's free will was undermined by a overriding directive to destroy the protoss. This was part of a greater plan by the fallen xel'naga Amon to remould creation in his own image. The Overmind disagreed with its directive but could do little to resist.
The Overmind realized that to continue growing the zerg would need to leave Zerus, and assimilated the behemoths, enabling its forces to travel into space. It had since detected the xel'naga worldships in orbit and these made a logical first target for new material. The first sign that the xel'naga had that something was wrong was when the Overmind severed the psychic link. The zerg launched an overwhelming attack on the worldships. The "greater whole" of the xel'naga were slain, an action which threw the xel'naga plan into turmoil.
The Overmind assimilated some of the xel'naga's knowledge as it processed thousands of xel'naga into itself. Amongst other things, the zerg learned of the protoss, the other great experiment; they would become the zerg's ultimate target for assimilation.
Shortly before the Brood War, the xel'naga temple on Bhekar Ro was unearthed. The temple housed a strange "phoenix-like" energy creature which absorbed the essences and genetics of both protoss and zerg.
At the end of the Brood War, Zeratul stumbled upon a protoss/zerg hybridization project overseen by Samir Duran; the project was for "a far greater power" to which Duran ultimately worked for. Thought not Kerrigan's project, her "rebirth into the Zerg Swarm" had expedited progress. Furthermore, Duran claimed the hybrid was the "completion of a cycle", and its existence was "preordained when the stars were young."
Duran's pronouncements on the hybrids being the "completion of a cycle" led Zeratul to seek out information on this new threat. However, he was suffering mentally for numerous reasons, such as the death of Matriarch Raszagal at his hand. Years after his discovery, Zeratul was located by a preserver, Zamara, and her terran "host", Jake Ramsey. They restored Zeratul's mood and exchanged information. According to Zamara, Samir Duran's experiments are a "perversion", and if his attempts to "unify" the species become successful, "a monstrous and powerful perversion of both protoss and zerg will be set loose upon the universe, and all that [the protoss and terran] know and cherish will fall in their wake".
Wings of LibertyEdit
On the lost world of Ulaan lay three prophetic fragments contained within shrines. The Zerg Swarm under the Queen of Blades had traveled there and occupied the area around them. Zeratul himself arrived, only to encounter the Queen of Blades. They clashed over what the future beheld. Kerrigan had already given up, saying their conflict meant nothing. Zeratul left shortly after Kerrigan, believing there was still hope. Zeratul then located the prophecies with help from Praetor Karass and his forces. Kerrigan attacked the protoss, and at Karass's urging, Zeratul escaped from Ulaan vowing Karass's sacrifice would not be in vain.
Zeratul traveled to the world of Zhakul, hoping to make contact with a trio of "immortal" preservers there to interpret the prophecy. However, a hybrid, Maar, had taken control of the Zhakul Guardians and was using the preservers as a source of energy. It stated "some SECRETS must remain HIDDEN" as it rallied the indoctrinated Zhakul Guardians to fight off Zeratul's enclave. However, Zeratul's forces defeated the Zhakul Guardians, killing Maar and freeing the preservers.
After hearing the preservers' interpretation, Zeratul believed the prophecy referred to the Overmind and resolved to get information from it. On Aiur, at the site of the Overmind's demise, Zeratul encountered the spirit of Tassadar. The spirit revealed the Overmind had been corrupted and enslaved, given an overwhelming directive. However, it created Infested Kerrigan as a free-willed leader in an effort to escape its destiny. Tassadar imparted a vision of a possible future, in which a mysterious being, the Dark Voice known to the Overmind as the "Fallen One", used the hybrids to take control of the Zerg Swarm in order to destroy the protoss. It proclaimed "as I was your beginning - so shall I be...your end." The protoss came to realize that killing Kerrigan had allowed this to occur. The protoss were eventually exterminated at the hands of the zerg, and the zerg were also later eradicated. Zeratul wondered whether the "Fallen One" was a xel'naga.
Meanwhile, Jim Raynor and his friend Tychus Findlay had been hired by the Moebius Foundation, led by Dr. Emil Narud and Prince Valerian Mengsk, in order to acquire pieces of a xel'naga device which was much younger than most other such devices.
Raynor later made contact with Emil Narud, the head of the Moebius Foundation, who revealed to him the artifact's xel'naga origin, explaining this was why Infested Kerrigan sought it as well. After collecting another piece, Raynor confronted Prince Valerian Mengsk, the heir apparent of the Terran Dominion. Valerian was not hostile, however. He told Raynor he would use the artifact to restore Kerrigan's humanity. Raynor agreed to work with him.
Still more temples have appeared on worlds such as Nemaka, Aridas (where the powerful Argus Stone was stored) and Bhekar Ro; the latter disgorged a strange energy creature which collected protoss and zerg genetics for unknown purposes.
At least some xel'naga buried and/or entombed their dead.
In mathematics and the arts, two quantities are in the golden ratio if the ratio between the sum of those quantities and the larger one is the same as the ratio between the larger one and the smaller. The golden ratio is approximately 1.6180339887. The golden ratio is related to the Fibonacci sequence and the Golden Spiral.
There are prophecies relating to the planet Braken, a protoss world with religious significance. These prophecies claim that "he who harnesses this world will someday wield a great power, sanctified by the ancient ones".
Kerrigan and Zeratul's RoleEdit
Kerrigan bantered with Zeratul on Char as a prelude to combat, where Zeratul told her: "Your coming has been foretold... You are part of the culmination. But not the end of it. You shall show the way, the path that must be taken, the realigning of old truths no longer valid. Yours is not the hand, but your very existence provides necessary instruction." Kerrigan did not treat the pronouncement seriously at the time.
The following are worlds known to have been visited by the xel'naga, many of them possessing relics of their presence:
- Amon (a 'fallen' xel'naga)
The xel'naga may have played a different role in the trilogy originally. An early cinematic depicted Zeratul warning Jim Raynor of the xel'naga's linkage with alien artifacts, that they were the key to their return. For the release of Wings of Liberty, this content was replaced with Zeratul giving Raynor information about Kerrigan.
The following section contains information from a previous version of StarCraft II which is no longer valid.
A development version of the map Echoes of the Future identifies the xel'naga as the ones who manipulated the Overmind to destroy the protoss: Overmind: The Xel'Naga had created me to eradicate their failed children - the protoss - in a battle neither species would survive. The Overmind also created Kerrigan to stop the return of the Xel'naga: Overmind: Yet my...daughter...remained. She alone would break the cycle. She alone would forge a future devoid of the hated Xel'Naga.