After a certain amt of damage, he splits into 3 shades of himself, and teleports to the ledges above. To reach ledge: swim up and then jump when you see the bubbles in corners of the room. Some ledges around the room can be walked on as well. When you are fighting a shade, you must complete a Heroic Opportunity to "reveal" the shade and make it take damage. Mobs spawn on the ground level as well, they keep respawning and drop nothing, attempt to ignore them.
