Templar (or Aiur Protoss)
With their highly advanced technology and potent psionic abilities, the Aiur protoss have long considered themselves the most powerful species in the known galaxy. Although they are not a prolific people, they have learned to bolster the ranks of their military with robotic war machines and to combine their intrinsic psionic ability with technology, thus producing some of the most effective warriors ever known—the Templar.
If the Aiur protoss have a weakness, though, it is their difficulty accepting change. They are bound by the Khala, a psionic bond that allows them to share both thought and emotion. The tenets of the Khala form a rigid path, and the Aiur protoss are loath to deviate from it in fear of losing all they have built. Now that the Conclave has been disbanded in favor of the new hierarchy, some Aiur protoss have accepted the Nerazim as their kin, but the old hatreds still remain beneath the surface.

Tal’darim
The Tal’darim are an ancient faction of fanatical protoss completely loyal to Amon. They have spent countless ages in unquestioning service, enacting the will of their god, and believing themselves to be the Chosen of the xel’naga. Hostile toward outsiders, the Tal’darim have little interaction with other protoss, and do not seem concerned with evangelizing their mission beyond their ranks.
They are currently led by Ma’lash, a brutal and unyielding ruler who is rumored to have been favored by Amon himself.

Nerazim
The Dark Templar were originally the rogue tribes and individuals who did not join the Aiur protoss’ Khala after a civil war known as the Aeon of Strife. The ruling Conclave kept the existence of the rebels a secret, but also wanted them eliminated. The rogue tribes were not hostile, but felt surrendering to the Khala would destroy their individuality.
Eventually the Templar, led by Adun, were ordered to hunt the rogues down in secret. But Adun could not kill his own kind. Instead he faked the executions and led the rogues away. Adun taught the rogues to use their latent psionic powers to hide from the other protoss, but the Dark Templar powers spun out of control, causing massive psionic storms across Aiur. The Conclave had little trouble tracing the storms back to their source.
Adun and his warriors refused to kill the rogues and threatened to reveal that the Conclave had kept their existence a secret if they tried to kill them. The Conclave agreed to exile them instead, loading them onto an abandoned xel'naga craft. Their exile from Aiur would later be known as the Discord. Henceforth, the rogues' became known as the Dark Templar, for they had forsaken the Khala's light.
The dark templar are more individualistic and work in smaller groups compared to the Aiur protoss who are more culturally monolithic. Each Dark Templar is encouraged to forge his or her own destiny and path, and they believe that fostering this attitude leads to their great successes.

Purifiers
The Purifiers were built under direct order of the Conclave to be an ultimate fighting force at a time when the scientists were making technological advancements in intelligent robotics and A.I. The program was originally kept in shadow and unified by the belief that consciousness could be turned into data, thereby used to preserve the thought-process and decision-making ability of a formerly living being. Studies proved that the replications were often 99.3 percent accurate to the protoss subject the replication was patterned after. The Conclave moved to use this technology to build a force replicated from the greatest warriors in history.
They did not, however, treat the Purifiers with the same respect afforded to regular Templar. Instead, the Purifiers were little more than slaves in the Conclave's eyes. Eventually, the Purifiers chose to rebel, killing their masters. In return, the Conclave determined that the Purifiers were too dangerous and banned them. They were powered down and launched away in a command vessel, Cybros, to be reactivated only in the direst of circumstances.