Disharmony of Flame requires you to slay Overmaster Pyron. This is a prerequisite for both File:Horde 15.png [52] Commander Gor'shak and File:Horde 15.png [54] The Last Element. Turning this quest in will cause both Vivian Lagrave and Galamav the Marksman to whisper you, and their two questlines will become available.