Kouchuu Gunshikan, Boukensha ni Naru

Kouchuu Gunshikan, Boukensha ni Naru summary: The spaceship which Imperial Galactic Navy Officer Alan Corinth helms is shot down by a surprise attack during hyper-space navigation. Completely due to freak coincidence, Alan is the only one in the ship to survive. The severely damaged spaceship loses its navigation capabilities and plummets onto a nearby planet. Using an escape pod, Alan heads toward the planet alone. Thus begins Alan's quest for survival on the underdeveloped planet utilizing the symbiotic nanomachines [Nanom] within his body. Surprisingly, the planet is home to a thriving human civilization whose genetic code closely resemble Alan's own. Even while remaining at a loss due to being thrown into a world of swords and magic, he tries to live as best he can together with his newfound comrades. What will Alan achieve in this strange world? The sci-fi fantasy story in a medieval setting now begins! (Source: Shousetsuka ni Narou, translated)