After I Transmigrated into a Book, I Became the Fiancée of the Heroine, the Arrogant Dragon

Lan Kou has loved reading novels since middle school, especially stories about strong female leads. Lately, she has become obsessed with one about a heroine who takes on the heavens, the earth, and even the emperor, then becomes emperor herself. She had imagined countless times that after she transmigrated, she would follow the heroine and make a name for herself. She never expected her wish to actually come true one day. But she never imagined she would run into a demon! What is going on? Isn’t this supposed to be an ordinary reborn + transmigrate + alternate-world novel? How did it suddenly turn into a fantasy novel after she transmigrated into a book?