@Yoshikage1234
There are very few universal evils, rape is definitely one of them, which is why of all the options the rapist is the only one that can be viewed as purely evil, no one can forgive that kind of character, especially when they are stated as sadistic and proud of such acts.
This is also why serial-killers (as a general rule) are also among the "special" breed that just can't be redeemed - attempting to sympathize with such characters is foolish at best and downright dangerous at worst.. which is why even the most forgiving characters will not redeem such a character.
The best hope is a forced "alliance of necessity" against a cataclysmic threat but much like Gollum inevitably betraying Frodo such alliances are doomed to failure if the forgiving forget that rapists and serial-killers, by in large, are monsters and treating them kindly most often just makes them wish to harm you more.