Liar Liar: Usotsuki Tenkousei wa Ikasama Cheat chan to Game wo Seisuru sou desu

The Academy—a school the size of an island where students compete for ranks. Not only did Hiroto Shinohara pass the most rigorous exam in the country with top marks to transfer there, but he defeated last year's reigning champ on his very first day, catapulting him to the rank of Seven Star in record time. ...Except he didn’t. The truth is, he screwed up big time, and now he has to maintain his position there no matter what. It's a liar's world, after all!

(Source: Yen Press)