My Thoughts Exactly

Ryu, a teenage boy with no respect for social norms, is starting his education as a magician; however, starting alongside him is his sister Ruri, a devil (in his opinion) who loves nothing more than to tease him and make his life miserable. A shameless boy, a sister who keeps him on edge and a city of students full of hormones. What could go wrong? Oh, and the world is at war.