Odin's notebook is a small black leather notebook carried by Odin Arrow. Inside is a hollowed out segment where he keeps a few leaves of Florem Mortem and his pipe for smoking. He uses the notebook to keep some kind of record, displaying a series of numbers and letters. The purpose of these records have yet to be revealed. He also uses the notebook to draw, doodling Ava after first meeting her.
On page 0568 there is a drawing of a fox in the corner of the book. This fox, presumably drawn by Odin, is the same as a fox plush Ava is depicted holding in one of the official prints.