In the years after the War Against Existance, many people tried to rebuild there infrastructures, re-establish government, bring law to order. Which is where we find Silverleaf. King Tony and Queen Zoey hear of many strange happenings around the Inner Sea. Uprisings of Devis and Demons in good cities in the name of a Demon lord, Dispater.
The party finds themselves setting aside their reparations to fight a new war, against a power hungry Deity and his army of hell spawn. But they will find that even evil will fight evil when said evil is out of line.