Munou Saijo wa Akujo ni Naritai ~Gimai no Migawari de Totsuida Reijou, Koushaku-sama no Dekiai ni Kizukanai~

Avril is a young woman of exceptional ability who was mistreated and labeled "incompetent" by her family. Avril marries into the family of an "old, lustful duke" in place of her half-sister, but the duke, Dylan, is actually a beautiful young man who is the complete opposite of what he is rumored to be. He wants to marry a "villainess," and a contractual divorce after three years is perfect for Avril's future freedom. The people around her are bewildered by the mysterious "brilliant woman" who plays the role of a "villainess" with gusto, but they are gradually drawn to her...