Runn was a mischievous male Dibbun otter resident of Redwall Abbey. He was the twin brother of Bagg and a good friend of Grubb. He, his brother, and Grubb saved the Abbey from the sea rat crew of the Darkqueen by using Friar Alder's best chopping knives to cut the rats' grappling hooks on the north wall of the Abbey, stopping a siege against Redwall.