adventurers needed to hunt down a magical animal

advenutrers met an observer, who informed them that they had tried to resurrect one of the dead lords and it had gone very badly. the lord lost all of his memories as well as transforming into a type of undead that is out for vengeance against the two lords that killed him. to be able to see him, they went to a oasis that transported them to the infero, where they drank water that allowed vision of the dead. they then found vrens "ghost" body watching the sunset on the coast. and after telling him that they were part of the group that caused this, as well as that the two remaining lords are evil assholes, vrens ghost said he had work to do and vanished into the woods.