Fallingwater Library. Ah, the great library. It is a massive, monolithic stone structure with carvings of Oghma. The books in this library are insanely varied, with all sorts of spells, including sound dampening, and charmed old Hags wandering the halls.
The Hags include Auntie Olga Pigtooth, and there is a single librarian.
Tasha, a woman with brown skin and a robe made of spider silk. She says that the Hags are evil creatures, and are fine to be enslaved. But she seems.... odd. Tasha is a Veiled Lord.
She is actually a powerful chain devil named Succoth-Yuggoth, who has made these Hags his fiends who murder people and sacrifice them in an altar in the library he claims is a sad artifact from a long time ago.
If killed, the Hags will thank the Heroes, all five of them, and use dimension door to move out of the land. Auntie Olga gives the Heroes a big kiss.
Out front, a few erudite citizens of the city sit on stone benches and read books next to the statues of Oghma littered in the front.
Occassionally, a wizard can be seen practicing tricks, his magical light illuminating the cobblestones.
In the back is a sculpture garden of gorgeous statues. There is even a small model of the Githyanki city of Ri-Tin to scale, even with small Githyanki figurines. A few guards with knight statistics ensure this area is safe.