Hello everyone!

So I bring Vaath's head to Rolkid and he tells me about the bounty. I think I let Guzud go but I went back to the caves to see if he was there (and he isn't). I go back to Rolkid to see if there is a dialogue option to tell him that he is at least defeated (and there isn't). And I went to Obould's lair to see if he was chilling with Guzud (and the door is still locked).

Is this sidequest ruined entirely?

I don't think you will see him again if you let him go. If you want to get his head, revert to an older save if you have one so you can redo this side quest. I believe you need his head to get a chance at Obould.

Thanks!