Combatants Will Be Dispatched!, Vol. 3 (manga) — Natsume Akatsuki

Agent Six's utterly unchivalrous tactics had been working wonders, but that all comes to an end when he and Alice are outed as spies and banished from the kingdom of Grace. How unfortunate that the Demon Army is preparing for all-out war at that very moment... Six might still be able to save his feckless former squadmates from certain doom -- but only if he's willing to gain an unfortunate nickname in the process!