Originally Posted by Words_of_Truth
Nagash heads to the the Black Temple and summons Dieter Helsnicht to help him perform a ritual, the ritual involves Dieter reading out the books of Nagash as Nagash descends into the spirit world where he ends up fighting Usirian, as Deiter fiinishes the incantations a great wave of souls batters the god of death and Nagash beats him down before eating him. Nagash has now pretty much become a god of death.
Still he won't win. The Skaven made sure he was killed once, they'll do it again.