I Became the Villainess in an Anticlimactic Novel

I became the villain of the novels I read. But this novel… …is a novel with an anticlimactic conclusion where the empire suddenly collapses right before the end! To hell with the original story! I have to try and survive first. So, I just tried to escape to the neighboring country beside us, but then… “I’ve waited for 100 years just to meet you.” The man who hid his identity as the Demon Lord and was the driving force behind the invasion. Grand Duke Arvis caught me with a gaze full of emotion. “If I lose you again… I might start by exterminating this continent that took you away from me.” …Why?