the servant is demon king

Synopsis. After the death of his grandfather, 19-year-old Kazuya Souma—an aspiring civil servant—is left all alone with no one to call family. Out of the blue, he is transported to the Elfrieden Kingdom, a small ailing country in another world, to be a "hero." An ongoing war with the demon army has put the entire world in peril, and Kazuya ... my stupid heart walk off the earth