Agathys, the innermost layer of Carceri, is a dark sphere of black ice. The wind howls endlessly, and little light or shelter can be found anywhere. At the base of one glacial cliff sits a tiny, lonely stone building known as the Library of Ignorance.

The library consists of a main level and a balcony that runs around three sides. Each wall of the building is filled from floor to ceiling with rows of bookshelves - all empty. None of them holds even a single book. In the center of the main floor sits a wooden table, a single chair, and a small, pot-bellied stove. On the table rests a tremendous volume whose cover reads “Book of Knowledge.”

The library’s sole occupant is a derro wizard by the name of Dreschm. Once, Dreschm was an adventurer who wandered the planes, learning all he could from anyone who would speak with him. Now he is irretrievably mad (even for a derro). Though no one is certain how he came to be in this state, it is presumed that somewhere in his adventuring, he earned the ire of Nerull.

Every day, Dreschm sits at the table and fills one page in the book with memories from his long-ago travels across the multiverse. However, since he has no other source of heat, he also tears one page from the book and tosses it into the stove to feed the flame. Despite the wretched conditions, Dreschm has no desire to leave his library, and will actively fight anyone who tries to “rescue” him or otherwise make him leave.

The Library of Ignorance is a planar touchstone, and grants information to those who know its secrets