In the year 2013 A.D, he was just an ordinary salaryman. He fired a co-worker, albeit for valid reasons, in order to get promoted and have a carefree life. After his ruthless actions, the fired co-worker found him at the train station, and pushed him down to the tracks in front of the high speed train, resulting in his death. Before he died, he met Being X for the first time. Being X failed to persuade him to believe in his existence, and so he reincarnates him in another universe as a blonde-haired and blue-eyed infant girl named Tanya Degurechaff, in order to spread his religion and force him to accept his existence.
The salaryman is reborn as Tanya Degurechaff in 1913 in an alternate universe, in a nation known as the Empire. When she comes to her consciousness for the first time, she realized she was in an orphanage. She lived at a church for a long time without changes in her daily life however, it exhumes until a group of specialists went to check all the children. Through a magical test, she was listed as a powerful child with an incredible amount of mana. Furthermore, she was proven as an unexpectedly born with a skilled set of magic. Therefore, she was a promising candidate for conscription into the Empire's Imperial Armed Forces. Realizing joining the military is inevitable and seeing it as an opportunity to better establish herself in the world, Tanya volunteers in order to obtain better treatment and opportunities that would most likely be absent as a conscript.