'Have you seen the barrow--hound nearby, Name? The others think they are just bleak, wild dogs, but I know better. These are no mere dogs -- they are barghests!
'In my travels some years ago, I once happened upon the most forsaken places I have ever seen. Dread filled me, and my voice died, and all was cold. The dogs there were the very same as these black, mournful beasts. with their eyes full of death.
'Why have they come to replace the lynx and wild aurochs herds that roamed here in Thorin's day? It does not make any sense. They must be driven off!'
The barrow-dwelling dogs called "barghests" have taken over the lands in Thorin's Gate, implying the presence of much death nearby....
You should defeat barghests, for they are a sign of an unnatural death in this valley that was once hale and fair.
You should speak with Unnar and tell him of your success in driving off the evil barrow-hounds in Thorin's Gate.