Gategun no Gaikoukan to, Ryuu no Kuni no Taishikan

Gategun no Gaikoukan to, Ryuu no Kuni no Taishikan (開門銃〈ゲートガン〉の外交官と、竜の国の大使館, lit. "Diplomat of the Gategun and Dragon's soil embassy") is a light novel series by