-This quest is impossible to complete on its own. You can only bring 9 companions to face 30+ troops. Using the highest tier archers possible and placing them on the side of a cliff so the enemy would have a tough time reaching them while being rained down by archer fire, they still all died...
My clues: Not bald, has a beard, no markings.
None of the contenders matched this description. The perpetrator ended up being bald as he was the last one I tried killing without failing the quest.
Additionally, sometimes the contenders don't appear on the map at all and it needs to be reloaded.