Manga Seduce The Villain's Father

I had one favorite novel that I always read because it helped me relax and unwind. One day I got into a car accident, and when I opened my eyes, I realized that I was in the world of this novel! However, there is a big problem. I am in the world 20 years before it began. But on the other hand, I have enough time to prevent a huge series of horrific events that await this unfortunate kingdom in the near future.
If you follow the original story, the evil emperor was supposed to kidnap my older sister, who is pregnant with the main character of the entire novel. However, my desperate attempts to thwart this incident led to the kidnapping of another person - me!
At the same time, my body is weak due to the influence of alien magic, and also uses it extremely problematically. But even stranger, I love being with the emperor who kidnapped me! Then it dawned on me, I can save him from the death that the son of the villain will bring him, and also protect myself from sinister magic by marrying him!
I thought that he was married and asked him to break the bonds of marriage, but what was my surprise when he said that he had neither a wife nor children ... It seems that the story is getting more and more mysterious!