Under the dictates of the Dae'Uhl, the Empire had a policy of non-interference towards 'lesser races,' who were unaware of the protoss' existence. Prior to the arrival of humanity at the galactic fringe, the Empire's territory reached across the Koprulu sector.
Over the course of a few hundred years, hundreds of worlds were incorporated into the Empire within the protoss's corner of the galaxy. Those who refused to conform were banished from Aiur, becoming known as the Dark Templar. The Judicator Caste would be composed of leaders and statesman, the Templar Caste of warriors and the Khalai Caste of artisans, scientists and builders. The Empire was formed out of the ashes of the Aeon of Strife, the mystic Khas developing a caste system through which protoss society would function.
