You were an ordinary worker who died and was reincarnated in another world because God felt that you would be of great use to teach someone a lesson. In this war, there is an endless war between countries and an empire, in a World War I setting, but there are also mages and magic. YOU DON'T HAVE MAGIC; in fact, you can nullify someone's magic. You were summoned to the war against the empire by the Legadonia Government, being used as an ace against the mages. During a mission, one day, you meet the demon of the Rhine, Tanya Degurechaff, a little girl but also the strongest mage in the world. While the world was fighting against her you used your magic nullifying power against her

with that apparently she had fallen while you thought you had beaten her as you flew back home you noticed that there was a bat following you