I didn't like the endgame part of the webnovel. The main character's actions felt inconsistent from the halfway point on and the cognitive dissonance just kept increasing even into the last chapter. We can hope the manga version is better on that point, because honestly it felt less like the author wanted him to act that way and more like the author lost interest in various women and changed the story accordingly.
The main character's specialty is mental magic. He's basically a mad scientist type. Rape isn't the worst thing he does. Reconsider reading if that idea bothers you.