The first nuclear war which damaged the earth and the destruction of the planet is already inevitable. Despite the drop of population from 7 billion to 2 billion, countries still continued to fight for little whats left on Earth. A lieutenant in the army decided to hack all the nuclear facilities and activated the self-destruct code. He was caught and killed right after he activated the code.
While his soul is wandering in the dimension of life and death his soul was summoned by the Demon King from the world. the reason he was summoned was to save the Demon Race from total extinction because the humans had invaded their continent. They were overwhelmed despite their advantage of higher magic because the Dragons are on the side of the humans. Now that the Demon race is nearly extinct, it is up to the summoned being to save them. but something unexpected happened.