Leo

Leo is a warrior who overthrew the Demon Lord together with Max, Fred and Yulia. Several years ago, he defected from the Kingdom of Bescar and founded the Gamma Republic in the northern part of the kingdom. While trusted by his subordinates and the people, the Kingdom sees him as a terrorist conducting an illegal occupation. He is a martial fighter with a heightened sense of smell.

(Source: Level 1 Demon Lord and One Room Hero Wiki)