Concubine's Concubine: The Poison King's Defiant Medical Concubine is suitable for you. The protagonist of this book was a young lady from the richest family. She was timid and weak. Her fiancé had set up a poisonous trap to threaten her, but in the end, she became an elite killer in ancient times. She had a story with a cold, bloodthirsty, and poisonous prince. The plot was tight, full of suspense and thrills, and the female lead was very well portrayed. I hope you like this fairy's recommendation. Muah ~😗