Mahou Sensou

In this modern magic action story, Takeshi Nanase is an ordinary high school boy who has a somewhat dark past. Due to certain circumstances, he formed a "fake" couple with his childhood friend Kurumi Isoshima, but otherwise, he lives a normal life. However, one day, he comes across a girl named Mui Aiba, in a uniform he has never seen before, collapsed on the school campus. This encounter changes Takeshi's destiny completely. Mui tells Takeshi that she is a magician, and she apologizes, for she turned Takeshi into a magician, too. What Takeshi once knew as one world is actually two — the world where magicians live and the world where humans live.

(Source: Anime News Network)