Zhaitan is beaten but not dead. Else we’d not have a single risen in orr in open world map.
Um, they explicitly say as of the end of PS (Trahearne’s words) that the Risen threat is STILL THERE. However, now the risen numbers will start to slowly but steadily go DOWN as the main ways for them to regain numbers is gone (Zhaitan).
Zhaitan could easily be dead forever, and the Risen still be a major threat. Remember, you are talking about a force which at a DEFAULT, is a nation worth of people and ANIMALS undead, + a lot more corpses….