From the introduction: The T’au exist near the Damocles Gulf, on the eastern fringes of the Milky Way galaxy, in Segmentum Ultima. As of M41, it is little different from any of a thousand miniscule xenos empires that exist on the fringes of the Imperium of Man, save for the fact that broader events of the Galaxy have conspired to distract most greater foes that would crush such a polity, allowing expansion when most would be destroyed.