A Psychopomp is a kind of spirit living in the Deep Umbra. They bring the Avatar of a person when they Awaken. They disappeared around 1450 CE, perhaps due to voluntary exile or banishment by the current paradigm. They have returned since the Avatar Storm to defend creation.
By possessing a willing Awakened mage, they can form a hybrid creature called an Anakim. The Anakim are mages who have been voluntarily merged with Psychopomp spirits. The Anakim used their newfound ability to manipulate souls to destroy the infernal citadels in which they were trapped.
This is a short chapter and explanation when you get through Ch. 6