Dressed as a Good-For-Nothing Third Lady, I Conquer the World by Complaining

When a dagger cut through the night, I realized that becoming the most unpopular third lady in the general's palace was not a tragedy, but a rebirth. The original owner was timid, ugly and talentless, and became a laughing stock for others. But I - I was a top killer in my previous life, but now I have to make complaints to survive? Don't worry, I have a "killer professional skill exchange system". Assassination, poison, disguise, intelligence... As long as you have enough points, you can exchange them all.