Rift Quest:Like Moths to a Flame  

Throughout the Scarred Mire you will find Shade Threshers. They will sparkle with interactivity. Once one has been activated engage one of the nearby undead in combat and bring him close to the Thresher. A beam will shoot from the Thresher to the undead effectively stunning the monster and making him very easy to defeat. Defeat five undead this way and return to Brianna for your reward.