Ansatsu Kyoshitsu (Assassination Classroom) Vol. 1

First volume of Assassination Classroom (暗殺教室) a manga series written and illustrated by Yusei Matsui. The plot of this manga is about a monster who has destroyed the 70% of the moon and now he wants to destroy the Earth. This monster will give humans one last chance and he starts a job teaching in a high school institute. The main goal of all students of his class will be to be to murder him, however he does not seem to have any weakness. 

This manga contains furigana