Sengoku Akira

 is the protagonist of the series.

3rd year, class 4, is the main character of the series, a Japanese schoolboy. He seems to be a bystander who reacts to events rather than choosing his own destiny. He is regarded by his fellow students as a lazy good-for-nothing. He is not much of a reliable guy but in times of peril he springs courageously into action that helps the group survival, and eventually making him the leader of the group. He also seems to have a crush on Rion but can't express his feelings to her since they are childhood friends