The Librarian
The Librarian is a favorite minor Discworld character. For those who may be unfamiliar with the series, The Librarian is an ex-wizard who underwent a permanent change of his morphogenic field during a magically cataclysmic event in The Colour Of Magic/The Light Fantastic, which, for my personal purposes, I tend to think of as one book in two volumes.
He finds he likes being an orangutan so much that he decides to stay that way. At this point, the wizards at Unseen University are so used to his new shape that, if you tell them there's an orangutan loose in the library, they're liable to ask the Librarian if he's seen it. He may be an anthropoid of few words (Okay. One word, to be honest. Ook. It's all in the pronunciation, you see.), but he knows how to wrangle a mean grimoire. I always seem to picture him much as he's described in Guards! Guards!, with his Special Constable City Watch badge around his neck, ready to try to stand to attention for inspection by Lady Ramkin and Captain Vimes.
Drawn in pencil on a rather gigantic piece of paper that had to be scanned in sections. The scanner software couldn't quite handle piecing together graphics files that big automatically, so it had to be done by hand. Unfortunately, one section scanned darker than the rest, resulting in a somewhat patchwork look. He looked a bit nicer on paper.