What makes brother/sister incest worse than parent/child incest?
Well obviously that would be equally as bad or worse. I just wanted to get ahead of any loopholes like cases in fiction where stepsiblings get together or something like Oedipus where he didn't realize until after that they were related (and even he at least had the decency to be so disgusted that he blinded himself). The case in the Villainess anime is no excuses, full-blown incest. That's what I meant.