Angel of Retrieval
There are absolutely celestials 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 Everlasting 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.