Magical Girl Apocalypse

Magical Girl Apocalypse, also known in Japan as Mahō Shōjo of the End (魔法少女・オブ・ジ・エンド, lit. "Magical Girl of The End"), is a Japanese action-horror magical girl shōnen manga series written and illustrated by Kentarō Satō. It began publication in July 2012 in the manga magazine Weekly Shōnen Champion, published by Akita Shoten, and has been compiled into eleven tankōbon volumes as of April 2016. The series is published in North America by Seven Seas Entertainment. A spinoff series called Magical Girl Site was later made.

Plot
Kogami Kii hates his normal everyday life and wishes for something to happen. One day in the middle of class, he looks out the window and sees his teacher’s head explode when a little girl hits it. He goes to the bathroom to calm himself, but when he gets back to the classroom, he finds most of his classmates killed by the same little girl.