The Villainess and the Demon Knight summary: Cecilia, daughter of a marquis, suddenly realized she was now trapped in an otome game as the infamous daughter. Sadly, there was no escape from her fate, and upon breaking her engagement, she was unjustly charged by the protagonist and forced into prostitution. Fate twisted her way when her initial customer happened to be Lucas Herbst, the protagonist's close friend and deputy leader of the Imperial Guards. Lucas's abilities were unimaginably powerful, making Cecilia tremble in fear, and she let him have his way. Come morning, she found herself within the Duke of Herbst's estate, astounded to discover a promise mark covering her lower abdomen, labeling her as Lucas's fiancée!