Like an Alpha Night Terror, the Night Swarms are white in color. They appear to have black edges on wings and tail in Rise of Berk so they can be differentiated from the other Night Terrors.
Behavior and Personality
Unlike the normal Night Terrors, the Night Swarms are very aggressive towards humans due to their lack of exposure. They can also be somewhat possessive over others, especially when they form a bond with humans, even to the extent of worshiping him like a leader and forbidding him from leaving.
The Night Swarm, due to the perpetual darkness and tranquility in the caves, are extremely sensitive to light and become disoriented from high sounds.