Something is killing and eating the people of Th'gil. This monster displays cleverness, strength, and a thirst for blood. The PCs have stumbled into this town. Will they leave by walking or by dieing?
From that silent place fear flows in unseen waves, like white fog. The shadows are many, and the wind breathes cold through the broken battlements and casements. Through it's frowning walls and dark window openings there's a lantern of the spirit which none see by but those who bear it.
In local legend, the Halls are fairly old, with stories of people disappearing going back for hundreds of years, said to be taken by the Faeries. In actuality, the Halls are much older.
"What you wanna go messin' around up in the mountains for? Ain't nothin' up there but snow, and wolves, and more snow.
Yer lookin' for the old tomb? Take my advice, boys. Let that tomb alone. There ain't nothin up there you ought be messin' with. No money, no treasure, no fame, just ice. And death."
Not named for an resident beast, but for the multitude of winding, mazelike passages fraught with danger.