Usirian was the sinister, faceless god of the Nehekharan Underworld. He is never physically represented, since such a fact would be considered sacrilege, but is continually invoked in Nehekharan funeral rites. He was a very revered god in all Nehekhara since, with the rise of the Mortuary Cult, he became as widely worshiped as Ptra himself.
Usirian was in charge of guiding all the souls of the dead, especially the souls of the Priest Kings, on their journey to the beyond, to judge them and to decide if they were worthy to pass to the other life. If he had led a virtuous life, he would be allowed to enter the golden fields of paradise. Otherwise, Usirian would shed the spirit to the howling immensities of the avern to suffer there for all eternity or, at least, until the funerary priests could return their soul and return it to the land of the living. An exclusive right of those born of noble birth is that it was possible to negotiate and reach a deal with Usirian to reconsider his punishment and mitigate it.
Worse punishment ran those who directly opposed Usirian, suffering their terrible punishment in the other world: Usirian denied entry to the golden paradise, and instead condemned them to the lowest levels of the Underworld, where a colony of Khepra beetles Nest in their bodies and gnaw their entrails for all eternity. The ancient Nehekharans believed that these carnivorous beetles were messengers of Usirian, and who acted as their agents in the mortal world, allowing the god to see through their eyes and be aware of all the sins committed by men.
His servants in the Underworld were the Horex, terrifying owl-headed warriors charged with guarding and protecting the Kingdom of Souls. The entrances to the temples of Usirian were flanked by towering basalt statues of these feared guardians.
Source
- Army Book: Tomb Kings (6th Edition).
- Army Book: Tomb Kings (8th Edition).
- Warhammer Fantasy RPG 2nd Edition: Lure of the Liche Lord
- Novel: Nagash, the Sorcerer, by Mike Lee.