Cardinal Woofy Paws

An evil, twisted villain who stalks the streets of Redwall in the form of a headless dog. Considered Public Enemy #1. None have heard the Cardinal's dread bark and lived.

Origin
As the legend goes, Woofy Paws was once a simple young pup living with a devout family who worshipped Zoraster. So influential were they within the Church, and so beloved was Woofy Paws with the congregation, that he was raised to the rank of Cardinal.

Then... came the day that all have learned to curse and regret.

A pack of vicious dog-haters, who objected to Woofy Paws' high status, crept into his home and severed his head in one stroke. However, the Cardinal would not die. No, instead, the holy magic with which he had been imbued turned dark, and he rose as a zombie to devour the living. All now fear Woofy Paws, and quiver at the sound of his name.

Alternative Theories
Some suggest that the Cardinal is in fact an evil martial arts master, Woo-fi Pauzu, polymorphed into a headless dog. This is equally plausible.

The theory that he is just an urban legend believed by incredibly gullible people is absolutely false, and must be discouraged.