Yeah, I could totally dig a rock with a face drawn on it. I’m not being sarcastic either. The underdog (underrock?) is an amazingly sympathetic concept, made all the cuter by things that aren’t supposed to have emotions to begin with. Wall-E anyone? (I mostly just watch animated movies and horror movies so I don’t know any adult examples...)
But to make a heinous character ‘redeemable’, you’d need to consider your audience. Some audiences would be more likely to accept a character who raped their ex-girlfriend/boyfriend, while other reader bases would flip out if a writer tried to redeem that character. And maybe that first audience would condemn a murderer while the second audience would totally forgive a murderer who murdered for a horrible selfish reason if he, say, saved a litter of puppies or was a really awesome big brother. I think there are unredeemable characters, but I think what constitutes ‘unredeemable’ varies from group to group and person to person. Hell, some writers might have a reader base that could forgive just about anything when the characters are done right.
I used to watch Breaking Bad with my mom. She started out liking Walt but after he betrayed a couple people she liked, she hated him, and the rest of the series, she stayed hating him no matter what he did. I loved him! There were a few things he did that made me cringe and go “aw, Walt! What the fuck?!” but I rooted for him until the very end. Course it wouldn’t help much if your whole audience was mixed like that, as some are, but I think knowing a little about your readers, if at all possible, helps with plotting out the flaws of your villains and heroes.
I know, I’m rambling. I do that when I’m half asleep.
But I’d like to hear more about these plenty of ways to make characters awful!