The T'au Castes are the rigid social divisions that structure every aspect of life within the T'au Empire. Each caste is born to a purpose, its members shaped by heredity, training and unwavering devotion to the collective good. This ordered hierarchy is the foundation of T'au society, ensuring that every individual serves the whole with singular focus.
Five great castes divide the T'au. The Fire Caste, or Shas, are the warriors who wage the Empire's wars. The Earth Caste, or Fio, are the engineers and labourers who build its technological wonders. The Water Caste, or Por, are the diplomats and traders who spread its influence. The Air Caste, or Kor, pilot its fleets and aircraft across the void.
Above them all stand the Ethereal Caste, the enigmatic leaders whose word is law and whose guidance binds the castes together. Marriage and cooperation across castes are forbidden by ancient custom, preserving a stability that the T'au believe has carried them to the stars.