Irregular's Rebellion

Irregular's Rebellion (イレギュラーズ・リベリオン) is a light novel series by Shizuku Ochi with illustrations by Ochau.

Plot
Huntis Harmillion is a young man aspiring to become a knight for the empire to combat monsters and even demons, and he in particular is more than qualified. Upon enrolling into the knight academy, he managed to score better results than the previous record holder in the history of the academy―and so did four other people, two of them with even better results than him. The top scorer of these five, Reece Regalgent, pulls these elites together to form Squad 00, also known as the Irregulars.

A year later, Huntis has been held back a year, his old squad is gone, and he's been made the leader of a squad of troublemakers known as The Worsts, with Huntis himself no longer having the desire or motivation to accomplish anything.