Story of a Country Girl Reincarnated as a Villainess Trying to Avoid a Bad End: I Tried to Become Stronger than the Last Boss Because I Don't Want to Die

A girl living in the countryside is attacked by a monster and meets an unexpected death. When she wakes up, she has been reborn as the villainess in the story of her favorite book! In order to avoid a life of "certain doom" in which she will be killed by the Demon King as the enemy of the heroine, she acquires the strongest power, but ends up embarking on an unknown route in which the Demon King proposes to her...!?

(Source: Manga UP!, translated)