The Duke's Daughter's Mission to Seduce the Demon King～Humanity's final gambit: a political marriage with the Demon KIng! ...Hang on, but what am I supposed to do if the Demon King is a girl!?～

Five demons launched a war against humanity, destroying more than half of its lands. Among them, the Demon King, who has killed more humans than any other, and a duke’s daughter enter into a political marriage, bringing the war to a temporary ceasefire. Cecilia, the duke’s daughter, sets out to win over and ensnare the Demon King, hoping to prevent the extinction of humanity. However, the Demon King is hiding a major secret…?