reincarnation/placed in another universe

"If you wrote me, then you can give me the throne!" Yoonsoo is the successful author of a popular fantasy series. Just as she's about to start work on a new series, Imperial Prince Einzen Kyte, the worst villain she created has kidnapped her into the world of her own story?!

After Seo Yuri gets into a car accident during a trip back home, she reincarnates into the novel, "The Song of the Moon," and becomes the elder twin sister of a side character who meets a destructive ending- Selena. Selena hopes to prevent the destruction of her family, however, she is forced to take the place of her runaway brother, Celestine, in the knights’ squadron! Will she be able to avoid the villainous Crown Prince, Ignis, and survive?!