A Stich in Time...
200 years ago, a cult for the demon prince Orcus created a gap to the shadowfell, connecting one of Orcus’s unholy sites to the world. A flood of skeletons, zombies, and fowler creatures flooded through the opening into the light of day. Cormyr dispatched full legions of the Purple Dragons (the famous military of Comyr, known for their discipline, skill, and loyalty) to eliminate the threat. They succeeded and sealed the rift.
To keep a watchful eye on the now sealed rift, Shadowfell keep was built on top of it. Decades of peace passed and the Village of Winterhaven arose within sight of the keep.
This peace was shattered 80 years ago when the Commander of the Keep (Sir Jerold Keegan) systematically slaughtering every resident in the keep. He was driven below the keep and dispatched.
Comyr’s leaders, fearing that the sealed rift’s influence would continue to weak havoc upon those station at the keep, ordered the keep to be abandoned and to collapse the upwer towers and wall with magic.