Complex sentence: Dagg, Silica, Arthur, and Aviana join Orin and his people in celebration, but then several Starflies arrive and reveal themselves to be the spirits of the past Ka-Khan, including the elder man from the hilt's projection.
Split into simpler sentences: Dagg, Silica, Arthur, and Aviana join Orin and his people there. Moments later, several Starflies reveal themselves to be the spirits of the past Ka-Khan, including the elder man of the hilt's projection.