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Seems like a variation on In the Blood or Villainous Lineage.
I did consider that, but I'm unsure. While I call it "evil" it's really more to do with the overwhelming, corruptive nature of the power when there's no restraints — though characters in-universe do see it as evil. The men of the family have stronger abilities and less control over it, and these two twins (as far as we know) used it for evil.
Currently Working On: Incorruptible Pure Pureness
This has the vibes of Gender-Restricted Ability, but corruptive power would be Drunk on the Dark Side
Those could work
Currently Working On: Incorruptible Pure Pureness
In Blade of the Moon Princess, we learn that an old branch of the family was exiled due to the evil actions of their heirs a long time ago. While the royal line is supposed to only produce girls, who have a certain level of control over their magic, the gene does not pass to male heirs. So when two twin boys were born, they had zero control over their powers and were both seen as bloodthirsty monsters who murdered their wives on their wedding day.
What I'm looking for is something, or perhaps multiple things, that can cover this scenario.