The Zombight invasion was a period during the Second War in which an ancient empire of ogre-like beings, dubbed Zombights, invaded from under Shadow Vale (which was at the time known as Brightvale). The entire valley was almost completely wiped of its inhabitants, and the Zombights would hold control of these lands for many years, attempting several times to further expand their "empire" outside of the valley.
Cause for the invasion Edit
It is unclear exactly why the zombights awoke at this point, and why they entered the above-ground in such a violent manner. It is possible that the creatures already had controlled the area long ago, and saw the new inhabitants as a threat. It's also possible that something else below-ground forced them out. Many of the caverns that link the zombights underdwellings with the outside world have been destroyed since the invasion, so getting inside of them without being killed by the zombights themselves has proved to be a difficult task.