The Dark Templar is a powerful ground unit that is permanently cloaked, even when attacking. When a Dark Templar is built it will randomly appear as either a Lenassa tribe (with "a single warp blade, and a cloth shroud [covering] its face") or Zer'atai tribe ("who wield dual scythes and wear an ensemble of heavy armor and the bones of slain zerg") Dark Templar. They will have the same stats, only differing in appearance.
Some protoss rejected this movement, believing that their individual identities would be erased to further the suffocating rule of the Conclave. They even went so far as to sever the long nerve tendrils that characterize the protoss. This act symbolically and literally cut them off from the primal chord of their race. The Conclave saw these rogues as a threat to the new order and charged the Templar caste with hunting and destroying them.
The templar, led by the idealistic warrior Adun, could not bring themselves to slay fellow protoss and thus hid them. The Conclave's fears appeared justified when Aiur was lashed by a wave of violent psionic storms unleashed by the undisciplined minds of the rebels. The Conclave was not willing to punish the templar openly for their disobedience because doing so would reveal the existence of the rebels. Instead, the dissident protoss were loaded aboard an ancient but functional xel'naga vessel and launched into space.
The exiled protoss wandered far before eventually making a new home on the twilight world of Shakuras. They developed a solitary and independent culture, with individuals often widely scattered across space in their own ships, exploring and contemplating the mysteries of the universe. Over time these dark templar have learned to wield a very different kind of psionic strength than that of the Khala: the energies of the Void, the dark spaces between worlds.
The dark templar are most renowned for their ability to bend light around their bodies to become invisible at will, and a true master of the Void can achieve much greater feats than this. Armed with their potent warp blades, the dark templar are deadly and relentless foes, capable of crippling conventional forces with their devastating strikes.
Though severed from their homeworld and feared by their own brethren for many centuries, the dark templar never abandoned their love of Aiur. In recent times they were reunited with the protoss of their homeworld when the heroes Tassadar and Zeratul joined forces to fight the zerg Overmind. The Overmind was defeated, but the planet Aiur was ravaged in the process and so badly overrun by zerg that the survivors retreated to Shakuras. Now the protoss who were once exiled find themselves playing host to refugees from their old home.
From January 8 to February 5, 2009, Blizzard held a poll in which the fans voted on whether to have the Lenassa tribe, the Zer'atai tribe, or both tribes randomly, appear in multiplayer matches. The players voted overwhelmingly for both tribes to appear (65% of voters), and both tribes appear randomly when a Dark Templar is built.