From Lotro-Wiki.com

Lore

Wargs are often deemed a scourge of Men because their preferred prey are the herds and livestock upon which many villages across Middle-earth so depend. In this regard they are much more scourge than the lesser breeds of wolves, for Wargs are known to wantonly slaughter livestock even after they have sated themselves, leaving entire herds to rot.

Rewards For Deeds:

Enmity of the Wargs I		Man of the Fourth Age	Your will is improved.
Enmity of the Wargs II		Return to Bree	This enables you to quickly return to Bree
Enmity of the Wargs III		Duty Bound	You provide a bonus to your fellowship's Morale.