I'm honestly confused aout the usage of the words "pure" and "corrupted" here..
I understand that some people don't like the sister in the relationship, but I don't think that
makes her generic of slutty. I'm pretty sure she still wants do be daddies number one.
But, even if we would cut the sister out, she would still be a corrupted girl, simply
because there is nothing pure in incest. Incest is, at least according to nearly all moral systems known to me,
inherently corrupt. Her being willing to engage in incest with her father means that she is willing to
leave the confines of morality which is not pure but corrupt.
I havn't played the game in some time, but I think that the fact that incest is not "normal" is actualy adressed, and taboos mean that their moral system prohibits such acts.