rift quest:Shadows of Regulos  

River of Souls World Event Rift: Patch 1.1

Accepting the quest gives you the buff Shadow Sight, allowing brief glimpses toward the Plane of Death, and the Sphere of Glimpsing.

With your Shadow Sight you can see the swirling pillars of Death energy around Sanctum or Meridian. If the pillar is hidden behind a tree or wall you can spot them by motes of Death energy moving towards the weak spot in the Wards.

Use the Sphere of Glimpsing to toss its power towards one of these vortices and a Shadow of Regulos (Umbral) will appear. It does not really matter if you kill it or not, as there are many in Sanctum or Meridian willing to help once the danger is visible. You will still get the quest credit when the shadow dies.

RIFT Wikibase™