Damn It! I Became the Nurturer of Original Evils

[Book title: Damn it! I became the nurturer of the original sins] [The password is a typo...] [Semi-invincible + succubus male protagonist + no sword + all characters in the book, male and female, can be the female protagonist, it all depends on the reader's preference + yandere] I, Kane Kaliya, am the 'holy son' born into the family of the holy woman. No, no, no, I mean, my sister Iya Kaliya is the real saint. I'm just her brother. But is there a possibility. This world is just another story in [my] eyes. In this story, I should not exist. And as a member of the Saintess family, I actually secretly raised the 'Original Sin'!