Dethbrush was a male fox and a soldier in Ferahgo the Assassin's army, the Corpsemakers.
He and a group of tracker rats were sent to follow Dingeye and Thura, who had deserted Ferahgo's army. Upon finding Dingeye, Dethbrush decapitated the stoat and took the sword of Martin the Warrior from him (the stoat had previously stolen it from Redwall Abbey).
Upon hearing about this, Samkim the squirrel tracked the fox down and fought with him in the Great Inland Lake. But before Samkim could defeat Dethbrush, the fox was dragged into the lake and killed by the Deepcoiler.