Forced to Sell Myself to the Female Lead After Killing the Male Lead

I am not that good with synopsis, So please read the first chapter instead.-----------After accidentally killing the male lead and changing the course of the story, our Demon Queen finds herself in a very complex situation.As the final villainess of this world, her mission was to be defeated while making the Chosen Ones stronger.But fate played a cruel trick on her.Left with no other choice, she finds herself forced to serve the Female lead to survive.As the story unfolds, our Demon Queen must navigate her new life as the heroine's servant while also trying to uncover the truth behind her sudden change in fate.