Crazy Soldier Has Reincarnated

Killed in a nuclear blast, Izumi Yanagi awakens in another world—a ruthless land ruled by powerful races, ancient forces, and endless conflict. Armed with an immortal body and the ability to recreate anything from his previous world, including humanity's deadliest weapons, he sets out on a journey in a world where humans stand at the very bottom of the food chain. Yet no one realizes the mistake they have made. They have given a second life to a soldier who loved war more than life itself. And this time, he brings the legacy of every human battlefield with him — Description from novelcodex.org