The Sword Coast Legends
Feathergale Spire is reported to be located in the Sighing Valley of the Sumber Hills.
It is reported that some kind of air cult has taken up residence in this ancient spire.
Feathergale Spire is one of the Haunted Keeps, an ancient ruin that’s purpose has long since been forgotten. Once inhabited by monsters, it appears that the keep has new residents.
In 1491 DR, a group of adventurers discovered that a cult had taken up residence in the tower. They assaulted the tower, wiping out the cult there and subsequently destroying the tower in the process. All that remains are the stables which stood built into the sandstone column the spire was built upon.