Three weeks ago, my sweet, little sister, Lina, was having her eighteenth birthday, and my family, who I thought were normal, average, everyday people, turned out to be the direct bloodline of the modern age gods, and for some reason they'd chosen my sister as the new Dark Lord; An insane, emotionally fragile, horny brat, that turns out, wants me to be her new Demon Overlord and... wife? Huh?!