The library of the unwritten / A. J. Hackwith.

"Books that aren't finished by their authors reside in the Library of the Unwritten in Hell, but when restless characters who emerge from those unfinished stories escape, it is up to the Librarian to track them down...and keep the collection complete. Many years ago, Claire was named head librarian of the Unwritten Wing--a neutral space in Hell where all the stories unfinished by their authors reside. Her job consists mainly of repairing and organizing books, but also of keeping an eye on restless stories that risk materializing as characters and escaping the Library. When a hero escapes from his book and goes in search of its author, Claire must track and capture him with the help of former muse and current assistant Brevity and the nervous and sweet demon Leto. But what should have been a simple retrieval goes horrifyingly wrong when the terrifying angel Ramiel attacks them, convinced that they hold the Devil's Bible. The text of the Devil's Bible is a weapon in the power struggle between Heaven and Hell, so it falls to the librarians to find a book with the ability to reshape the boundaries between Heaven, Hell...and Earth"--