The Regressed Villainess Takes a Vow of C*astity

Lydia Evansi, born into a prestigious marquis family, with wealth to spare even after lavish spending, and blessed with a beautiful face.
The only thing she lacked was good judgment in men. She fell for a prince of humble birth, sacrificed everything to help him become emperor, even fulfilling his dream—only for him to have an affair with her cousin Giselle. Emperor Richard then used the child in Giselle’s womb as an excuse to take away the empress position he had promised Lydia.
Lydia planned to die by poison alongside Giselle, but failed. Abandoned even by her only remaining family, her brother Devon, she was dragged to a harsh and miserable labor camp. Soon after, a plague struck the cold, wretched camp, killing all the companions she had relied on. Lydia too, with trembling pale hands, quietly awaited death. If she could go back to that time, she would want to slap herself hard. And then, a real opportunity came. She returned to that very afternoon when she was poisoning Giselle’s teacup—she regressed to that teatime!
She resolves to take revenge on Richard who abandoned her, Giselle who deceived her, and Devon who traded her life. To do this, she needs the Empire’s Sword that everyone covets: Arsen Edis. Lydia approaches Arsen, boldly reveals her regression, and asks for his help. Half-doubting, Arsen decides to believe and watch over her for now, beginning to live with Lydia.
But… Arsen’s gaze toward Lydia gradually becomes strange?