Enter the portal that opens in the center of the room; go all the way to the back of Warder's Dominion to kill The Final Arbiter ( -1364, -185, -87 ) Copy/waypoint -1364, -185, -87
Imprint the essence of the four Warders
Target the four epic dragons around the room and use the Essence Crystal on each
Although they are aggro they will not attack if you stay out of their circle (just run around the edge of their platforms)