Quick Transmigration: I'm the Male Lead's Wicked Older Sister

I open my eyes. Who am I? And where is this? "System 413 at your service." What System? This is a deal to recover your memories. This is a world where immortals and demons mingle. Jiang Yu, the chosen one of this world, is the son of a cultivator and a demoness. You shouldn't have anything to do with him, but unfortunately, you share a father, though not a mother. As an illegitimate child, you were scorned by the righteous sects, and you made his life difficult at every turn. Sadly, the big shot awakened his power later on and dealt with you first. The big shot later returned to the warm embrace of the demon realm and launched a war between immortals and demons, devastating all life in the mortal world. In the end, a grand blood-sacrifice formation from the cultivation world sealed him away, and peace returned to the mortal world. Your mission is to stop Jiang Yu from destroying the world and prevent the devastation of all life. In return, the System will restore your memories. Now, begin your challenge!