The legend of The Doom Slayer is one that has been etched into the hearts of many for generations. A simple human man who somehow made his way to Hell and slaughtered legions of Demons. His strength unmatched, his rage unparalleled. But one day, The Slayer disappeared, and has laid dormant ever since. Years have gone by. How many, no one knows. In that time, the Demons have evolved from their primal and animalistic state into beings that could be considered Human. However, there is a split among Demon kind. There are those that would continue the path of blood and invade Earth, and there are those that believe that Earth should be left alone. This split among Demons has erupted into a full on civil war. Those that wished to kill kept the Demon monicker. Those that wished to leave Earth alone became The Devils. Both sides have established schools dedicated to teaching combat to the younger generation, so that they may help win the war. One such school is Sopitam Academy, an all girls combat school for The Devils. One such student is Lillian, a Devil who believes that Humans should be left alone. One day, while in the library, she discovers a book that tells the tale of The Doom Slayer. She already knew the basic tale, but this book told information about The Slayer that she didn't think possible. In his dormant years, The Slayer had a son. As if that information wasn't surprising enough, a Human boy somehow finds himself accepted into Sopitam.