The Dark Templar have "sharper" features than the Khalai, and perceive things differently.
Nerazim often cut off their psionic appendages, and developed the use of special clamps to control the energy bleed. These clamps can also be used for Khalai protoss who lost their own psionic appendages by accident or in battle (particularly with the zerg).
Nerazim technology is similar enough to Aiur technology that these protoss can intuit how to use the technology.
Driven by individuality and a thirst for knowledge, the Nerazim developed along a very different path than the Khalai. They remain willful and often fiercely independent, with their closest allegiance being first to clannish warrior bands and then to the Nerazim, the great tribe to which all Dark Templar belong. By their nature the Nerazim are a diverse group of freethinkers motivated by their regard for one another and tribal bonds rather than abstract notions of authority. Different clans take great pains to distinguish themselves through variations in weapons, armor, markings, and dress. Regardless of clan, reputation and personal responsibility are paramount in the eyes of any Nerazim: individuals must always be accountable for their actions. As a result, deeds rather than words act as the dark templar's guide. Individual clans can be prone to feuding and rivalry, but they are quick to band together against a common threat, such as that presented by the zerg.
The Nerazim maintained the same system of writing as the Khalai. Unlike the Khalai however, female Nerazim are able to become figures of authority.
The xel'naga retain the position of "gods" in Nerazim religion.
Some, if not all Nerazim appear to store their dead in mausoleums and crypts.
Before officially becoming a Dark Templar, one undergoes a Shadow Walk.
Dark Templar were taught to hide from the Conclave by the powerful TemplarAdun. This ability has been described as "bending light" and "merging with shadows".
Dark Templar wield the energies of the Void. These energies are harmful to the zergcerebrates and Overmind due to the similarities of the cosmic energies they wield. The Dark Templar consider their powers to be the "true gifts" of the protoss, and consider the Khala to be diluted and narrowed by the (former) leaders of the protoss. Their own powers are considered "wider". This power protects Dark Templar from zerg infestation.
Anything that "taints" the Void is considered unholy by the Dark Templar.
Dark Templar are cut off from the preservers; they have no preservers of their own, and their memories cannot be accessed by the preservers. As they are severed from the Khala, communicating with the Nerazim via telepathy requires Khalani to actually be spoken rather than the essence of thoughts being expressed.
A group of protoss survivors stranded on Aiur, the Tal'darim, were cut off from the Khala and developed abilities similar to those of the Dark Templar.
"As impossible as it may seem, there are some among us who would destroy everything we have sought to build over the last millennium. They question the Khala. They maintain that the right of the individual takes priority over the good of the whole. Some have even resorted to the extreme measure of self-mutilation in order to sever their connection to the Khala."
A few rogue tribes refused to submit to the Khala, believing that their individual identities would be erased to further promote the rule of the Judicator Caste. Although they were not hostile or militant, they believed that the communal agenda of the Conclave would be the eventual doom of the protoss. The rogues held no ill-will toward their brethren and attempted to live their lives unnoticed as best they could. Nonetheless their existence was known to the Conclave.
Approximately one thousand years before the Great War, the Conclave, under the leadership of Kortanul, had collected records on the locations of the Rogues. The Conclave ordered the ExecutorAdun to report to the Conclave so they could tell him about this new threat, which they believed could cause a new Aeon of Strife. Adun was given Raszagal, a young prisoner, to question. He brought her to the Citadel of the Executor so the other Templar could question her. The Conclave gave him their information so he could quietly track down the rogues, abduct them, and execute them.
Adun was unable to bring himself to execute the Rogues. He transmitted fake recordings of the executions to the Conclave and hid the Rogues, even teaching them how to cloak. The Rogues ended up developing these abilities more quickly than Adun could teach them. Unfortunately, the Rogues, still learning their powers, lacked the discipline of the Khala. They inadvertently unleashed psionic storms, which spiraled out of control on Aiur. The Conclave discovered the corpses of dead Rogues, only to realize these Rogues had been depicted in the execution recordings.
The Conclave could neither punish Adun nor slay the Rogues, as he would force them to publicly admit the existence of the Rogues. The Conclave decided to banish the wayward Rogues from Aiur forever on an ancient, but functional xel'naga ship, along with other protoss ships which Adun insisted they be allowed to take with them. However, last-minute squabbling threatened the Rogues, and Adun feared they might accidentally create psionic storms again. Adun created a blue mist with a combination of Khala and strange energies, which covered and protected the Rogues. However, the power caused Adun to burn out like a star.
Shortly afterward it was discovered that the exiles had stolen the powerful Khalis crystal from the Sargas Tribe (the tribe from which most of the exiles stemmed) and taken it with them.
They ceremoniously cut off their nerve-appendages to show their disdain for the Conclave and the Judicator. This act cut them off from the Khala, forcing them to draw their psionic energies from the void. As their legend spread across Aiur, sparking the imaginations of many young protoss, this tale worked to incriminate them. Although they were hunted and feared by their own brethren, the Dark Templar never abandoned their love of Aiur and worked to safeguard it in any way they secretly could.
During this time the creation of the dark archon was banned. They developed their fleet of Corsairs, vessels designed to defend themselves as they had traveled through the stars.
The first step on the Dark Templar's journey was the moon of Ehlna, which they discovered shortly after leaving Aiur. It had a xel'naga-crafted warp gate, so the exiled protoss stayed. They discovered the moon had a combination of energies which altered khaydarin crystals, making them quite efficient at storing memories. Without preservers, the Dark Templar had no other way to store memories, so they used this technological means. After more than two centuries, the Dark Templar departed, but some remained to operate a shrine, the Alys'aril, where the memories could be extracted from pilgrims and stored. Numerous vessels remained behind as well.
Struggling to adapt to their harsh and nearly lightless environment (protoss feed on light), the Rogue Tribes altered their skills and even their biology to cope.
Some tribes would live in other star systems and aboard small ships.
Eventually Raszagal, age 1045 in 2500 and one of few Dark Templar who was old enough to clearly remember Aiur, became Matriarch of the Dark Templar. She ruled for approximately five hundred years before the outbreak of the Brood War.
The Dark Templar were greatly concerned about the zerg and chose to test themselves in battle against small bands of zerg on Char. The zerg proved frighteningly resilient and numerous, and so the Dark Templar brought the Khalis to Char so that they might try to wield its energies against them.
While Tassadar diverted Kerrigan, Zeratul killed Zasz and became temporarily linked with the Overmind.
Zeratul infiltrated the primary zerg hive clusters and assassinated two cerebrates. The Conclave saw the results of this and admitted via Aldaris they were wrong about the Dark Templar. Zeratul participated in the assault on the Overmind, which ended when Tassadar channeled Dark Templar energies through the hull of the Gantrithor and crashed it into the Overmind, destroying it.
Zeratul banded together with Aldaris, PraetorFenix and Commander Jim Raynor in order to unite and lead the Khalai survivors. He offered to shelter them on Shakuras and found them passage to the warp gate. On Shakuras, the Dark Templar rescued the refugees when they were ambushed by hydralisks.
Raszagal welcomed the Khalai to Shakuras and ordered the death of two cerebrates who had infested the temple grounds. The Dark Templar were instrumental in this. It was then that Kerrigan arrived and Raszagal, who had been mentally enslaved by Kerrigan, asked the protoss to accept Kerrigan's assistance. While Kerrigan and Zeratul assisted Praetor Artanis and the Executor in securing the Uraj and Khalis crystals, Aldaris began an open revolt against Raszagal, who in turn ordered his death. Zeratul felt something was wrong with Raszagal, who was normally gentle, but followed her orders, even authorizing the creation of dark archons to match Aldaris' forces. Kerrigan killed Aldaris before he could reveal Raszagal's secret, and Zeratul banished her from Shakuras.
Raszagal claimed that she was wearied by recent events. With her encouragement, Zeratul carried the Khalis to the crystal while Artanis carried the Uraj. They channeled the temple's energies, resulting in an explosion which obliterated the zerg on Shakuras.
A combined Templar and Dark Templar force left Shakuras to conduct a mission on Aiur; the rescue of a number of wounded protoss warriors abandoned in stasis cells on the world. The protoss had to fight their way past zerg colonies to do so, but when they reached the stasis cells, a quartet of Dark Templar appeared and destroyed two of them (killing the protoss within). They were forced to surrender before they could destroy the third cell.
These Dark Templar were led by Ulrezaj, who hated the thought of harboring Khalai on Shakuras. He claimed that slaying the high born Templar was a sacred act. In a demonstration of protoss unity, a tribunal consisting of protoss from Aiur and Dark Templar sentenced Ulrezaj to imprisonment. The trial was interrupted by an attack of terrans. Early in the attack, they freed Ulrezaj and his minions, who stole a number of khaydarin crystals before fleeing.
Ulrezaj had created an alliance with Alan Schezar and his Scavengers, who had previously used khaydarin crystal-based techniques to control a cerebrate and thus an entire brood. Their plots included using warped khaydarin crystals to control and mutate zerg until they could withstand the power of the xel'naga temple and to use a powerful EMP Generator during battle against the protoss of Shakuras. Their plan involved unleashing the enhanced zerg upon Shakuras, which would cause the Dark Templar to flee to their hidden places, leaving the protoss from Aiur exposed to assault. However, the plan partially failed; a combined Khalai/Dark Templar force destroyed his warped crystals.
Raszagal was kidnapped by Kerrigan's minions when Talematros was destroyed. Zeratul traveled in a carrier to Char Aleph, demanding to know why Raszagal had been taken. Kerrigan revealed that she stole Raszagal to use as leverage in getting him and his brethren to kill the Overmind for her, but Zeratul had reservations. He obeyed only when Raszagal asked him to do it for the sake of the protoss. Zeratul and his dark templar went to the surface of Char and killed the Overmind. Zeratul then demanded that Kerrigan release Raszagal at once. However, when Kerrigan asked if she wished to return to her people, Raszagal replied that she wished only to serve Kerrigan and remain at her side. Zeratul realized that Kerrigan had corrupted Raszagal's mind.
Zeratul circumvented Kerrigan's defenses and rescued Raszagal before regrouping with a number of protoss survivors on the surface of Char, but Kerrigan and her broods closed in before they were capable of dimensional recall. Zeratul dealt Raszagal a mortal blow rather than let her be recaptured. In her last moments, Raszagal thanked Zeratul for freeing her from Kerrigan's control and named him the new leader of the Dark Templar. Feeling unfit to succeed Raszagal, Zeratul went into self-imposed exile.
In the proceding years, leadership of the recombined protoss civilization fell to Hierarch Artanis, who struggled to maintain unity against the deep-seated distrust and resentment between the Khalai and Nerazim. Raszagal's name was frequently invoked to keep the peace.
The prior zerg invasion of their world caused the Dark Templar to become more battle-hardened. The Dark Templar combined their technologies with those of the Khalai. Their collaboration produced astonishing new developments, including the void ray and the stalker. Although the Nerazim were counted as part of the Daelaam—a united protoss people, internal tensions led to tribalism in both the Nerazim and Khalai,
Judging the total power of the Nerazim is almost impossible, for most are nomadic folk scattered across dozens of star systems in small ships and hidden enclaves. It's quite possible that their combined strength is enormous.
The idea of making the Dark Templar arms/armor predominantly platinum comes from development of the stalker, which was made platinum in order to distinguish it from similar-looking zerg units. The concept was later applied to the Dark Templar as a whole.
↑Tassadar: "A powerful psionic call drew my attention to a remote, barren world named Char. Apparently, the call was answered by others as well. For upon Char, I encountered those who were once our brethren - the Dark Templar." StarCraft. Vivendi Games. Mission: Into the Flames (in English). 1998.
↑Overmind: "Yet shall their overweening pride be their downfall. For when the assassin Zeratul murdered Zasz, his mind touched with mine, and all his secrets were made known to me. I have taken from his mind the secret location of Aiur, the Protoss Homeworld." StarCraft. Vivendi Games. Mission: Eye for an Eye (in English). 1998.
↑Zeratul: "Greetings to you mighty Tassadar. I knew that you would not forsake us. For in the time that you have spent with us, you have learned to value our ways and our methods. You have learned to channel our dark power as well as that of your masters; thus, you alone have found completeness beyond the scope of the Khala. But I fear that the Conclave, in its pride, could never bring itself to welcome outcasts such as we." Tassadar: "Outcasts though you may be, it is your vision and courage that may yet save our Homeworld from the Swarm. I beg of you, Zeratul, return with us to Aiur. Though they are petty, and have, in ignorance cursed your kind for generations... help me save our people." Zeratul: "Since our banishment long ago, we have never failed in our responsibility to Aiur. Though it shall cause us great pain to see our homeland once more, we shall return with you, Tassadar. We will do what we can." StarCraft. Vivendi Games. Mission: Into the Darkness (in English). 1998.
↑Tassadar: "Executor! Aldaris! This madness must stop! The sight of my brethren slaughtering one another is more than I can stand. Though I fear you would doom us all, Aldaris, I surrender myself to the Conclave. En Taro Adun, Executor. Don't give up the fight!" Aldaris: "Tassadar of the Templar, by your actions you have severed yourself from the mercy of your brethren. You refused to destroy the Terran worlds as was commanded. You have questioned time and time again, the sacred will of the Conclave. And you have abandoned your Homeworld in its darkest hour. Most grievous of all is that you have allied yourself with the blasphemous Dark Ones, and learned to utilize their profane powers in tandem with our own! What say you, oh fallen Templar?" Tassadar: "Aldaris, I submit myself to the Conclave's judgment. But know this, given the same choices again, I would surely have made them. I have sacrificed all that our world might live. I have sullied my honor, I have discarded my rank and standing, and I have even broken our own most ancient traditions. But never think that I would, for one moment, regret my actions. For I am Templar, and above all else, I have sworn to Protect our Homeworld 'till the end." StarCraft. Vivendi Games. Mission: Homeland (in English). 1998.
↑Fenix: "Zeratul and his Dark Templar have vanished, leaving us to fend for ourselves. I wonder if Tassadar was mistaken to have put his trust in them." StarCraft. Vivendi Games. Mission: The Trial of Tassadar (in English). 1998.
↑Zeratul: "Stay thy hand, Judicator. The stewards of Tassadar shall not fall while the Dark Templar live. Call off your guards and stand aside, and you may yet live to see another moonrise." Aldaris: "I will not be addressed so by one so devoid of the Khala's light. You and your vile brethren shall die with these traitors." Zeratul: "Are you truly so blinded by your vaunted religion, that you can't see the fall ahead of you? Your Conclave believes that they are winning this war, but all they've succeeded in doing is helping the Overmind to win." Aldaris: "What could you possibly know about our designs, blasphemer?" Zeratul: "You speak of knowledge, Judicator? You speak of experience? I have journeyed through the darkness between the most distant stars. I have beheld the births of negative-suns and borne witness to the entropy of entire realities... Unto my experience, Aldaris, all that you've built here on Aiur is but a fleeting dream. A dream from which your precious Conclave shall awaken, finding themselves drowned in a greater nightmare." StarCraft. Vivendi Games. Mission: The Trial of Tassadar (in English). 1998.
↑Aldaris: "Executor. Tassadar. This comes too late to you. But the Conclave has witnessed your defeat of the Cerebrate. They know now that they cannot deny the necessity or the valiancy of your actions. We sought to punish you, while it was we who were in error. You represent what is greatest in us all, and all our hopes go with you. EN TARO ADUN, brave Sons of Aiur!" StarCraft. Vivendi Games. Mission: Eye of the Storm (in English). 1998.
↑Raszagal: "Congratulations, Executor. Your success has brought us the promise of hope against the Zerg. However, we face a new threat within our own ranks. In your absence, Judicator Aldaris and an entire legion of Khalai survivors from Aiur have begun an open revolt against us." Zeratul: "By the gods, this is ill news indeed! Why would Aldaris betray us so?" Raszagal: "He and his ilk believe that it was wrong to have abandoned Aiur and consorted with our people. Their prejudices have driven them to perpetuate the Conclave's sins against us! Even now, Aldaris and his loyalist templar forces are preparing to attack our Citadel." Artanis: "I can scarcely believe this. As if the Zerg were not enough! Matriarch, are you certain of this?" Raszagal: "All too certain, young templar. Executor, as Matriarch of the Dark Templar and custodian of this world, I hereby order you to terminate Judicator Aldaris, and quell this untimely uprising without delay! There will be no dissent among us while the Zerg are poised to strike!" Zeratul: "There is something amiss here. The Matriarch has always been a wise and gentle soul. Though there is some merit in her decision, this is very unlike her." StarCraft: Brood War. Vivendi Games. Mission: The Insurgent (in English). 1998.
↑Aldaris: "You can no longer afford to be so naive, Artanis. While you were securing the crystals, I discovered that your Matriarch has been harboring a dark secret! She has been manipulated by de-" Kerrigan: "We have no time for this!" Zeratul: "Kerrigan... What have you done?" Kerrigan: "I just cleaned up your mess, Protoss. Don't be so squeamish." Zeratul: "Wretched creature! This was a Protoss matter; you had no right to interfere! Begone from this world! You are no longer welcome among us!" Kerrigan: "Fine. I've done what I came here to do. I've insured the destruction of the renegade Cerebrates, and I used you to do it. Have fun, mighty Protoss... We'll be seeing each other again, real soon..." StarCraft: Brood War. Vivendi Games. Mission: The Insurgent (in English). 1998.
↑Zeratul: "Matriarch, I have served you for many millennia. I have always valued your wisdom and strength. Yet lately, in your mind, I have sensed something that clouds your true spirit. Though Kerrigan has gone, I wonder if her treachery still remains?" Raszagal: "Be at ease, Zeratul. I am still the same Raszagal you have always known. These recent events have weighed heavily upon me and I am wearied. But fear not; my warrior spirit will shine before you, and light your path to victory." Zeratul: "Indeed." StarCraft: Brood War. Vivendi Games. Mission: Countdown (in English). 1998.
↑Zeratul: "Kerrigan, this is Zeratul. I demand to know why you've taken our Matriarch." Kerrigan: "Actually, Zeratul, she's not the one I'm truly interested in. I stole her to get to you. You see, I need you and your brethren to kill the Overmind for me. The only way I had of assuring your cooperation was to take away that which you value most. However, I give you my word that once you've killed the Overmind, I'll allow her to return to you." Zeratul: "As if your word held any value..." Raszagal: "Zeratul, my faithful servant. You must aid Kerrigan in this endeavor. The Overmind is our common enemy. It must be destroyed to insure that our people will survive!" Zeratul: "You ask me to aid this vile creature?" Raszagal: "I do not ask this for myself. Nor do I ask it on Kerrigan's behalf. I ask you to do this for our people, Zeratul. Obey me as you always have... Trust in my judgement." Zeratul: "Very well, Matriarch. The Overmind will die this day." StarCraft: Brood War. Vivendi Games. Mission: To Slay the Beast (in English). 1998.
↑Zeratul: "It's done, Kerrigan. The Overmind is dead as you wished. Now I demand that you release the Matriarch at once!" Kerrigan: "Of course. Raszagal, do you wish to return to your tribe?" Raszagal: "No, my Queen. I wish only to serve you and remain at your side." Zeratul: "What treachery is this, Kerrigan? This pathetic creature cannot possibly be Raszagal!" Kerrigan: "Ha ha ha. I promised that I'd allow her to return to you, Zeratul. But it looks to me like she doesn't want to go." Zeratul: "You have corrupted her! Somehow you have poisoned her thoughts. Restore her to her rightful self, or you will pay dearly for this offense, Kerrigan!" StarCraft: Brood War. Vivendi Games. Mission: To Slay the Beast (in English). 1998.
↑Zeratul: "Damn you, Kerrigan, for what I must do!" Raszagal: "Thank you, Zeratul... You have freed me from her vile control at last. You have always served me with honor... Thus I must ask you... to watch over my tribe... Into your hands I give the future." Kerrigan: "I can hardly believe this! You've killed your own Matriarch!" Zeratul: "Better that I killed her, than let her live as your slave, Kerrigan." StarCraft: Brood War. Vivendi Games. Mission: The Reckoning.