Cats can protect...there was a book a few years ago about a lady and her tiny blind kitty who lived in NYC. Someone tried to burglarize her apartment and little Homer fought so hard one of his claws ripped off in the burglar’s face. Flat out embedded in the guy’s cheek...
Cats typically nip or give you a small scratch to let you know they don’t appreciate what you’re doing, or it happens in the struggle to get away in the case of something like pilling or defleaing a cat. Most don’t actually see a cat in defense mode rather than escape...they go for the throat and eyes, and I have very little doubt one could blind or kill. Paw full of claws to the neck vessels...