The first crypt is an abandoned desert ruin where the Cult has disposed of books it doesn't want people to read.
The second crypt lies along the montains, north of the Ashwan Desert. This abandoned mountain ruin is full of hidden mechanisms. The Cult uses the crypt to dispose books it doesn't want the people to read.
The third crypt as the Librarian calls it, is the tomb of poet-king Azur. The Cult uses the crypt to dispose books it doesn't want the people to read.
The fourth crypt lies in a cul-de-sac along the coast, east of Ashwan Desert. It is reputed to be a massive labyrinth built as the entrance of a long-crumbled fortress. It would eventually become a mass graveyard after thousands of soldiers died within its twisting passages during attempts at laying siege.