The [[Ethereal]]s serve as "philosopher kings", and guide the other castes, as well as alien member-races of the Tau empire, towards the enlightenment of the ''[[Tau'va]]'', the [[Greater Good]]. They serve as the undisputed rulers of the Tau Empire. Their unique role is a combination of spiritual and political duties, and their declarations shape and steer every action of the Tau Empire. Were an Ethereal to order a Tau to kill himself, he would be met with instant obedience.{{Fn|6}} Ethereals themselves rule from the [[Ethereal Council]], with the [[Ethereal Supreme]] being the highest ranked of the Caste. They are in turn protected by the [[Ethereal Guard]].