Anime about a boy getting chased through a school?
I think the anime you are looking for is Magical Warfare, the events you described are from the first episode.

The strong man is Takao Oigami



The pretty boy should be Kazumi Ida




  Takeshi Nanase is an ordinary high school boy who has a somewhat dark past. 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.