Sister-In-Law of the Heroine in a Childcare Novel

A woman is reincarnated as a minor villain in a childcare fantasy, a petty imperial princess destined to become obsessed with the heroine’s older brother, poison the heroine, and meet a miserable end. Determined to avoid that fate, she cuts ties and prepares to run away, but after saving the heroine, everything starts to change. Instead of following the original story, the people around her begin acting strangely protective and possessive. As she tries to escape to the peaceful life she dreamed of, she finds herself increasingly entangled with a family that refuses to let her go.