At the source of the Wargs in Pren Gwydh are goblins training the vicious monsters as steeds, which are then carelessly released into the wild to roam as they wish.
'I believe this goblin-band has a chief somewhere within this camp. They are slovenly, but they are organized as well in their efforts. These Wargs are trained, vicious, and unfortunately intelligent.
'You should defeat whoever or whatever is behind these terrible beasts leaking out into our lands.'
The chief of the Warg-riders is somewhere within the Howling Caverns.
You should defeat Mange-rider, the chief of the Warg-riders.
Goronu can be found outside of the Howling Caverns in Pren Gwydh.
You should inform Goronu that you have defeated the chief of the Warg-riders.
Luned is in Galtrev, waiting anxiously to hear of the vicious Wargs that roam the landscape of late.
You should tell Luned that you have brought down many Wargs and their riders and hopefully rooted out the source of the evil that entered these lands.