Where's the series where the daughter is cucking her mother by fucking with her father in front of her?
I think we could make a series about this where the girl somehow forces her father into letting her rape him whenever she wants, and force the mother to be her cuckolded slave that gets abused.
Perhaps she also rapes her mother on the regular as well, she does all this despite being barely out of her toddler years, and this requires some explanation.
Remember that episode where a little boy had the powers of God?
He could get anything he wanted from anyone at any time, and it was only when he was denied what he wanted that he started to behave and feel genuine joy.
Might be a situation like that, or something more toned down like mind control or blackmail (could be as simple as threatening to complain that her parents are sexually abusing her using the evidence from her sexual assaults on them), whatever the case the girl is unusual in that she's horny, a genius and a psychopath.
Maybe she's had her adult mind that went back in time to her body in the past when she was a child.