Cache #2 in our Discworld series, placed out on 12th March 2017, to mark the anniversary of the death of Sir Terry Pratchett
The Librarian is a faculty member, and so he must have once been a human wizard. A strong wave of magic, altering reality, transformed the Librarian into an orang-utan, Pongo pongo, The Librarian's colleagues found that he liked being an orang-utan, and fought all efforts to transform him back to human. The Librarian found out that opposable toes come in very handy when climbing up the book-shelves and sorting books. Also, a very large and strong orang-utan has more plausible arguments when talking about dog-ears and overrun return deadlines. Although the senior wizards looked very hard for one, there are no rules in the university constitution forbidding an orang-utan to be a member of the college council.
The Librarian is a member of the Librarians of Time and Space, and has the understanding of the power of L-Space, and has used these powers to appear at certain times to ensure the safety of particular books, bringing them home to his precious Library at UU.
When worried, the Librarian tends to hide under a blanket in his book-lined nest in a cubby hole under a desk in the middle of the library. He is generally naked but he does wear an old green robe after he has had a bath.
Despite his usually easy going nature, it should be noted that the Librarian is an ape rather than a monkey and is extremely eager to correct people on the subject in uncharacteristically violent ways.
An interesting footnote: The collective noun for a group of orang-utans is a buffoonery.
https://wiki.lspace.org/mediawiki/Librarian