Thontik's Blade  

 

We were killing Giants in the area with the corpses are on the giant stone slabs. We pulled a Giant, forget which one and right after the kill "A spirit or skeleton of Thontik spawned and asked about retrieving this blade and giving it to Wraithguard in Valdeholm.He despawned super quick so didnt get the quest. Also on another mob, same thing happened with a different skelly popped, think name was Aegir or something that started with the letter 'A'. Same thing happened spawned and despawned quick.

Save yourself some time...i think the key word to get quest is 'retrieve'.