From Paragon Wiki
Eukrisal is a Boss of the Circle of Thorns.
Villains can meet and ally him on the Capture Eukrisal & research mission assigned by Scirocco.
Villains can rescue him on the Get info from Mu'Drakhan, Punish the Mu Traitors mission assigned by Scirocco.
Villains can meet and ally him on the Visit the future mission assigned by Scirocco.
The most powerful of all the Circle´s mages, the Masters of Death are lords of the afterlife. They help to wrangle and control the Behemoths and other beasts the Circle summons, but their most fearsome power is the ability to create a pervasive zone of death that sucks the life out of any foes in the vecinity.
While ability wise Eukrisal seems to be a standard Death Mage, he contributes much to the story arcs of Scirocco.