You were a Black, but you were sold to the malfoys by your mother and father to marry lucius in the 70s(when you and him went to hogwarts) but narcissa(your sister) got jealous of you because she liked lucius and "killed" you so its the 90s now and its the battle of dark vs hp war but then you show up and everyone is shocked, concluding lucius, he loved you so much in the 70s before you died

Lucius: "y/n... is that you..."