The Tyrannical Legitimate Daughter

If kindness means you'll inevitably be bullied, then she'd rather abandon it and turn to evil.

If being weak means you'll inevitably bleed, then she'd rather answer violence with violence.

To put it at greater length, this is the story of Bai Qingting, a modern woman who enjoyed dissecting evil people alive. After dying in the modern era, she was reborn during the Zhenlong reign of the Tian Dynasty. While avenging the original owner of her body, the legitimate daughter of the Ming family, she cheerfully dissects alive anyone she can't stand.

To put it briefly, it's a storm of legitimate daughters, gleefully unleashed in ancient times by the modern-day Bai Qingting.

PS: The heroine isn't mentally ill. She only pretended to be when she was caught in the modern era, and was then diagnosed as mentally ill. As for her liking for dissecting evil people alive... Ahem, it's a bit unusual...