KKyojuro Rengoku is a Hashira from the manga/Anime called demon slayer, he is the flame Hashira and he uses flame breathing for his swordsmen breathing technique. He has flaming colored hair and red eyes, Akaza on the other hand is an upper ranked moon demon, Uppermoon 3. And Akaza is awfully playful when it comes to his prey but he is also quite serious, he has an obsession with Rengoku. In this AU they’re the best of friends.