Akuyaku Reijou Level 99 ~Watashi wa UraBoss desu ga Maou de wa Arimasen~

A Japanese female college student is reincarnated as Eumiella Dokness, the hidden boss of the otome game Hikari no Mahou to Yuusha-sama (or HikaYuu). The game had a deep RPG system, which was the protagonist's favorite part. Having been reincarnated as the overpowered hidden boss of the game, naturally our protagonist sets about training in order to take advantage of her good fortune.

And so when she enters magic school, where the game's story would begin, she has already reached level 99.