I Tamed a Tyrant and Ran Away

Charlize Ronan was a child, unloved by her family, who volunteered to be experimented on and became the national treasure ego sword of the emperor for 400 years. Her cries of pain and sorrow fell deaf to the emperors who owned her throughout all that time, when suddenly she awakes again in the past in her original human form. This time, she vows to take revenge on her family and the entire empire for the pain and suffering by teaching and raising the genius prince to become a tyrant and destroy the kingdom. Once done, she leaves and disappears, believing her role to be complete.