Angel of Retrieval
An expert angel that people say knows when an item from a Library is stolen or grossly late in being returned. They sneak into your home, take the book or item, and then...they make you pay the late fee. They. make. you. pay. ~ Kisa, Curators in The Stacks
There are absolutely devas that retrieve stolen books or overdue texts and studies from the Libraries. But breaking into your home? Violence? Making someone "disappear". Utterly ridiculous. The Stacks wouldn't stand for such a Librarian to act in this manner. ~ Meliori
Variations & Mutation
Some use the Angel of Retrieval as an explanation of stolen or lost goods.
People in the Steppes don't believe such a being really exists that would go to the lengths the stories say while people in further regions indulge in them.