The Ready-Made Queen

Princess Violetta, who was exiled because she was developmentally challenged, is assassinated by a group of unidentified men. Ebigail, her faithful servant, is waiting for her own death to come when she's saved by Lakiel, the Duke of Edelgard, who says to her, "I will make you Empress." Many destinies are changed that night, as the imperial palace's biggest deception starts.