"Warp Fields Stabilized" -An Arbiter upon emerging from a Stargate The Arbiters were Protoss spacecraft that served as support units for the Protoss fleet. They were exclusively crewed by Judicators, the caste of Protoss leaders and government officials, whose powerful psionic powers could warp space-time. The Arbiters were retired during the Brood War, as the Judicator caste was destroyed after the fall of Aiur.