Gwaeron's Slumber was a sacred forest located west of Triboar. It was a place of reverence for worshipers of Gwaeron Windstrom, the god of tracking, and the followers of Mielikki, the goddess of the forests.
The Lord Protector of Triboar forbade anyone from hunting wildlife or woodcutting in this forest for fear of angering Gwaeron, who was thought to roam amidst the trees. Much of Gwaeron's Slumber was ruled by autumn, remaining unchanged by the passing of the seasons.
Sometime in the early 1480s DR, an oni who resided in the nearby hillside stalked and hunted rangers who would come to rest at Gwaeron's Slumber, disguising itself as Gwaeron, and leaving little to no trace of itself or its victim. The disappearances gave life to the claim that Gwaeron would spirit away his worshipers.