The Library of the Unwritten by A. J. Hackwith

Books that aren't finished reside in a library in hell.  The librarian there has to make sure the characters don't escape.  Claire is the current librarian and when a hero gets away, she has to follow him and bring him back.  She takes her assistant who is a muse and Leto, a demon that showed up right before she was leaving...

Ace and Net Galley let me read this book for review (thank you).  It will be published October 1st.

They have to travel by raven to where's he's gone, taking the head of the Arcane division of the library with them.  Their travels are full of danger because they have angels after them, one member of the group will betray her, and she finds she's related to the demon.  Even hell has conspiracies...

Their enemies burn the book the hero was in and it disables him.  The demon becomes more human as days go on, they fight monsters and angels, and then Claire has to go back and save her library.

Will she manage to do it?

This is a good read and young readers as well as adults should enjoy it if they enjoy fantasy.  I sure did!