When a Clueless First-Person Shooter Player Falls into Another World (Manga) Vol. 2 - Saiki

SCISSORS BEATS PAPER. LEAD BEATS EVERYTHING. Schwarz is an FPS gamer from another world, and when he set out to defeat a flock of harpies in an effort to earn his keep in this new fantasy realm, he thought he had a pretty good chance. But when a huge and lightning-fast ocypete, the ruler of the skies, appears, he discovers a single rifle might not be enough. If Schwarz is going to survive in this world of magic and monsters, he's going to need some bigger guns.