I understand that he's semi letting him go due to his sister's own personal desires. But honestly, he's scum that deserves what's coming for him. If he's truly regretting his actions, then good for him to suffer eternally in this way. Though honestly it's pretty lenient considering that he could just rip his soul, reincarnate him, wipe his memories selectively, tear his soul apart, reconnect his souls, make it into a chimera, etc etc etc.
And also, all of the attempted trickery was obviously not going to work on Raoul. Again, he's a god at this point. And he has shown that he can read minds and souls.
I'm more interested in if he's going to do the heroic thing at the end of it all after tearing out all the villainy of the world through his obsessive revenge and recreate the world into a righteous one, since he still displays heroic tendencies.