Tensei Akujo no Kuro Rekishi

Konoha Satou has a secret past; she used to write some spicy fantasy romance stories during her teenage years. But now she gets stuck in one of those stories as the evil villainess. She survived there because she remembered every detail about the story. With that, they managed to escape from some frightening situations. During her journey, she met Yomi, and she completely forgot that she had even written about him. Yomi says he is on her side, but she can’t trust him because she never wrote about him.