Apodemus was a male mouse Abbot of Redwall Abbey. He was described as having a yellow neck and being stout and fat. Apodemus was close friends with Malbun Grimp. He kept a list of troublemakers, called "Abbot's Report", primarily used when the Dibbuns were in some kind of trouble. After the failed trip of Crikulus and Malbun to locate Brockhall, Apodemus tried to get some information about the trip from Crikulus in his sleep; it wasn't very successful, as he was interrupted by Memm Flackery, who woke up the shrew.
Apodemus was also a good friend of Ovus, though several beasts thought he was too soft and not strict enough with the fussy old bird. When the Abbey was threatened by Zassaliss, Harssacss, and Sesstra, Apodemus put into motion a self-imposed siege, forbidding anybeast to leave the Abbey until the threat had passed. He then asked Ovus for help - the owl and Bluddbeak fought the adders, but were both instantly slain. Apodemus was devastated by their loss, and said a special poem in their memory.
Later, he welcomed Trisscar Swordmaid and her companions into the Abbey when they were being pursued by Princess Kurda and the Freebooters. Once this situation had been resolved, the Abbot made the unusual decision to let the Sword of Martin be carried across the seas to Riftgard Fortress, where Trisscar used it to defeat King Agarnu and free his slaves.
- Apodemus' name is derived from the scientific name for a wood mouse, Apodemus sylvaticus.