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.
After the PCs defeat (or force the rapid retreat of) a villanous necromancer/demon summoner, they discover a book. This book outlines how to summon a demon whose power increases according to the size of the summoning circle used to summon it. And after the PCs examine a map of the country, they find that the layout of the cities and roads match up with the required summoning circle. In fact, the final road that would complete the circle is currently in construction.
With anyone who can find out about the circle and the ritual to summon the demon able to somehow make the final road/line, and destruction of the cities and roads currently in existence out of the question (unless this is an evil campaign- that removes the moral quandary), how are the PCs going to solve this problem?