Inquisitor Olof: "Lets see, yes, you could probably assist me. I've heard of the dangerous Nightsisters that has (good english) developed a strange symbiosis with some other creatures than the rancor. I'd appreciate it if you could find out whats going on out there."

On accepting...

Inquisitor Olof: Good, I know they have their base of operations somewhere in this area."

A waypoint gets created pointing to what I can only presume is the new Nightsister cave just to the west of Singing Mountain.