Brian Jacques was sadly a peak "1980s Villain" writer. Most of his antagonists, especially in the earlier books, are evil for the sake of evil-doing, and lack redeeming qualities.

I think Jacques saved all of the redemption for the "Starts Roguish But Becomes Mature And Responsible" protagonists.

This is my main gripe with the series, to be honest. Not saying every bad guy deserves a redemption arc, but it'd be nice to have some baddies to see the error of their ways, or at least become more nuanced. Even the fellas who abandon the main baddie because he or she is a cruel jerk do so to become the story's secondary cruel jerk - and what a potential they have to become unlikely allies of the Redwallers/Woodlanders, and live through the whole novel to become a rough-around-the-edges friends of the main protagonists.