High Quality Content by WIKIPEDIA articles! In the universe of Games Workshop`s table-top wargame Warhammer 40,000, the Tau Empire is race of aliens inhabiting region of space on the eastern edge of the Galaxy, roughly 300 light years in diameter but having more stars than average for its size. The Tau were first introduced to Warhammer 40,000 in late 2001, the result of Games Workshop`s plan to introduce a new race to the game.