The Villainess and the Demon Knight (Manga) Vol. 2 Mature

Marquise Cecelia has awoken in the bedroom of the infamous Demon Knight, Lucas Herbst. His rough style of love has left the night before a blur, but apparently he's claimed her as his fiancée! Political shake ups have saved her from disgrace and losing her status. But Lucas's warped love will keep her on her toes... or her back...