This is a strange and amusing little manga. A powerful alien shows up on Earth and promptly destroys three fourths of the moon. He then demands to be given a class full of students to teach, and thus is placed at a prestigious Japanese school.
He is given class 3-E a lower ranking group of students. The Alien which is named Koro Sensei by the students, has an offer for the students and mankind: If the students can kill him in a year he won't destroy the earth. Koro Sensei even gives them a material to use in their weapons that can harm him
The assassination scenes are a lot of fun in this book and there are also some really meaningful scenes with Sensei and his students, he really cares for them and helps them move through personal and educational blocks.
I'm so curious to see how this series ends. It was a tremendous success in Japan but the creator has stated that he will still follow his initial creative arc. Such a fun read for the summer!