Khalai Caste

The Khalai Caste were the working class of the Protoss Empire, serving alongside the Templar and Judicator castes. As artisans, scientists, and builders, they formed the great majority of the protoss population, and their labour and learning sustained the civilization that the warriors defended and the priests governed. They are not to be confused with the Khalai, the broader kindred of Aiur protoss who followed the Khala; the Khalai Caste was specifically the lowest of the three castes within that society. Though their contributions were valued by the other protoss, the Khalai Caste held the humblest rank, and its members did not receive the rigorous mental training the other castes did, often leaving them with weaker psionic powers and senses. (StarCraft; StarCraft: The Dark Templar Saga: Shadow Hunters; Carrier)

A caste defined by the Khala#

Before the advent of the Khala, each protoss tribe had a definite proclivity or strength of its own. When the Khala came, its dictates advised a three caste system into which each tribe fit easily, and the vast majority of protoss tribes were gathered under the Khalai Caste. Where the Templar bore arms and the Judicators governed, the Khalai made and studied and built, and it was their work that supplied the foundations of protoss society. Their most common creation is the probe, a robotic worker built to raise colonies on worlds too hostile for living builders. They were valued for it, yet they were also reckoned the lowest of the three castes, and they were not given the rigorous mental discipline afforded the others. As a result, members of the Khalai Caste often possessed weaker psionic powers and duller psionic senses than their Templar and Judicator counterparts. The caste maintained a research retreat upon Endion, where its scholars could study in isolation from the rest of the Protoss Empire, and it counted the Furinax Tribe among its number. (StarCraft; StarCraft: The Dark Templar Saga: Shadow Hunters; StarCraft II: Legacy of the Void)

Forced to bear arms#

Despite the caste's traditionally non-combatant role, the Great War signalled the beginning of changing times for the Khalai. The Furinax Tribe fought for the Conclave against Fenix and Jim Raynor when they moved to free Tassadar from his trial for treason. As the war on Aiur ground on against the zerg and the number of Templar diminished, many of the Khalai were compelled to take up weapons, the Shel'na Kryhas standing as a prime example. At some point the caste also began developing a new Purifier program on the planet of Glacius, where it maintained a research base. Members of the Khalai Caste continued to dwell on the protoss colony worlds, but there they became a target of the Terran Dominion, and many were abducted for experimentation in Project Gestalt. (StarCraft; StarCraft: The Dark Templar Saga: Shadow Hunters; StarCraft II: Legacy of the Void; StarCraft: Frontline Volume 3)

Rebuilding the Armada and the loss of the Khala#

Many of the Khalai were instrumental in helping reconstruct the Golden Armada, built with the intention of retaking their lost homeworld. In 2506, Hierarch Artanis launched the Reclamation of Aiur, with members of the caste such as Phase-smith Karax supporting their Templar brothers. The operation failed when Amon corrupted the Khala and brought many of the protoss under his control. Artanis gathered what uncorrupted protoss he could, the Khalai among them, and fled aboard the Spear of Adun. (StarCraft II: Legacy of the Void)

Over the course of the End War, the Khalai Caste was forced into an ever larger combat role. The facility upon Glacius was besieged by Tal'darim forces under First Ascendant Alarak, and only the intervention of Daelaam forces saved the Khalai's research into the new Purifier program. The colony of Endion was overrun by Amon's brood, killing all 800,000 Khalai scientists stationed there along with the contingent of Templar that guarded them. Throughout the war Karax laboured to modify the Keystone into a weapon against Amon and to uncover the purpose behind its creation. (StarCraft II: Legacy of the Void)

The dissolution of the caste#

During the Daelaam's assault on Revanscar, the Spear of Adun was boarded by Moebius Corps and hybrid forces, leaving Karax to command the assault on the facility. The operation succeeded, saving the Daelaam from destruction and ending both Moebius Corps and Amon's hybrid production. Karax's bravery, in spite of having been born a Khalai, showed Artanis that the age of the caste system was at its end and that the time had come for all protoss to become Templar. With that, the Khalai Caste was dissolved. (StarCraft II: Legacy of the Void)

By the end of the conflict the Khala itself had been destroyed. Without the Khala and with their caste gone, many among the former Khalai felt a complete lack of purpose and a deep loneliness, unable to commune with the greater whole of their race or to confront the sadness within them. Many came to feel that they no longer mattered to the protoss as a whole, even as the survivors set about forging a new and unified society. (StarCraft II: Legacy of the Void; One People, One Purpose)