Deadnose was a ferret in Slagar the Cruel's gang. Along with Fengal, a weasel, he laid a false trail by taking the gang's cart up north and leading Matthias and companions with them. Later on, Deadnose and Fengal left the cart and went back south towards Slagar and the others, but later ran into a swamp after being attacked by Orlando the Axe.
There is some question as to Deadnose's species, since, while he is introduced as a ferret, he is later described by Cheek as a weasel. Later, Matthias confirmed this by looking at Deadnose and Fengal's tracks. However, based on the former reason, it is thus inferred here that he is indeed a ferret, not a weasel. It is possible that referring to him as a weasel was a mere misidentification, as weasels and ferrets are related. In the Redwall TV Series, Deadnose is portrayed as a ferret.