Tet

The universe, the god head, everything in one. In some sense, every other god is simply an aspect of Tet. This means that the Asti are simply expressions of the most abundant sides of Tet, and that a change in Tet or it's nature could result in the death and or birth of Asti. This is the very process that the Emperor attempted, trying to change the nature of Tet to make the Emperor himself a god. This is the first time that the Asti took notice of mortals, and it did not leave a pleasurable impression in their minds.
Tet is not sentient in the traditional sense. It is beyond that concept. In the same way that the non-sentient cells make up a sentient person, the sentient mortals and gods make up something... more. Tet is truly incomprehensible.