The God-Machine creates angels for reasons only it fully understands — each with its own purpose in the grand design. Once created, an angel’s role and the tasks that fall within its purview are fixed for as long as it exists. The God-Machine can transform, upgrade, or destroy its angels, but it seldom does. While the God-Machine commands a vast number of such servants and has created each one distinct in its capabilities, methods, and appearance, nearly all fit within a few broad categories called Incarnations. When an angel turns from the God-Machine to become a demon, it retains its Incarnation.
Some demons, however, chose to turn on their creator completely by abandoning their Incarnation. A Destroyer who despises violence and becomes a pacifist or a Messenger who swears to tell the truth is called an “antinomian.” These demons take the Fall to an entirely new level and strive to find a whole new purpose independent of their former Incarnation. Such demons are known as Antinomians and are respected and regarded with suspicion alike.
In addition to the "canonical" four, rumors abound of a rare fifth Incarnation: the Analysts, former spies and investigators of the God-Machine.
Demon: The Descent Incarnations