This boss fight consists of both an air phase and a ground phase. Talking to the Expedition Commander will begin the event with Razorscale in her air phase. The air phase consists of defending the Expedition dwarves while they repair the harpoon turrets. During this phase, the focus should be on defeating adds, and staying out of Devouring Flame. DPS on the boss is possible during this phase but only serves to shorten the boss fight slightly, and only if you can spare a DPS member or two.