The Brecilian Forest is a dangerous place with a long history of murder and death. It is passed quite often by The Dalish tribe led by Zathrian, who approach the forest in caution and in the knowledge of its deadly nature. Many dangerous things inhabit the forest, such as sylvans, shades and (more importantly to the storyline) werewolves.
As part of the main quest, the Warden must travel to the Brecilian Forest and enlist the aid of the Dalish there (who agree to call the other tribes together to help fight). However, when the party arrives at the forest, they find it in a state of confusion and panic. Keeper Zathrian then explains the camp has been attacked by werewolves. This is not the first time it has happened, although previously it was never in such an organized manner. Zathrian asks the party to venture deep into the forest and retrieve the heart of Witherfang, which he believes will heal the injured elves.