I Switched Bodies with the Villainess as an Otome Game Heroine

[Preorder goal: 500] Lilia was a frail heroine in a dangerous otome game world. Ever since regaining her self-awareness, she had been trapped in an infinite loop, reaching a bad ending in all nine consecutive playthroughs. She had already grown disheartened and lost all will to live. But who could have guessed that her fate would change dramatically in the tenth playthrough? The game's villainous princess used some kind of magic to switch bodies with her, then smiled like a victor. “Lilia Vandock! From today on, I'll take over your life! Your lovestruck men, your identity as the prophesied maiden, everything!” Lilia paused, frowned at the other girl's smug expression, then took her hand with a deeply earnest look. “Good luck! You can do it!” The villainous princess: ??? Director, this isn't what the script says! * Codina, the eldest princess of the Tritonco Empire, was a thoroughly wicked woman with a terrible reputation. Everyone hated her, like a rat crossing the street. But lately, people had noticed she was acting strangely, ever since the young master of the ducal house broke off their engagement for the sake of the Vandock family's daughter. “Sewing? Don't worry, I'm best at this sort of thing.” “Is this really the strongest knight order in the country? I can take them all on without breaking a sweat.” “Herbal medicine? Come on, everyone knows this much.” Everyone: ??? Was this really their uncultured, constantly wicked, ornamental princess? * For a better quality of life, far from the power struggles of the royal family, Lilia decided to move. She planned to move to the Demon King's castle, since it was exceptionally bleak and deserted, with plenty of potential for improvement. So here's the question: how was she going to move to the Demon King's castle? Easy. She'd make the Demon King fall in love with her and become the lady of the castle! So, when they first met, she grabbed the hand of the famously gloomy and cold-blooded young man, her eyes sparkling. “Please, you have to marry me!” The Demon King: “...What?” * 1. The heroine is a true Demon King. 2. The pairing is with the Demon King, but there will be plenty of intense love-triangle drama. Theme: Perseverance and hard work