Prelude-A million years ago

Once upon a time, there was a monster that hated the world and thus kept destroying it. One day, an ordinary high school girl stumbled upon a box and acquired superpowers to oppose the devil. A new journey, destined to be extraordinary, has begun. Could the girl defeat the monster? What would she encounter? A lover? Friendship?Who was the indifferent teenage boy?Read on and join the odyssey!