>>99991625Basically, there are several different species (or, "races") in Redwall and the "bad" species are defined as "vermin". Vermin are rats, ferrets, weasels,wildcats, etc.
Characters that are vermin are ALWAYS evil and the protags always distrust them just at a glance. If you read the books, there are even moments where the protags will openly talk about how much they hate vermin and how they're evil from birth.
In Outcast of Redwall, there was a weasel orphan taken in by the abbey, but everyone there treated him like shit because he was a weasel, and thus; vermin.