Betrothed to My Sister's Ex (Manga) Vol. 3

A KNIGHT IN BLACK ARMOR

Having been invited to attend a ceremony at the royal knights' headquarters, Marie is suddenly thrust into public life, where she's quickly scrutinized by Count Kyros's friend, Prince Luifon. With comments about her appearance and her lack of noble manners, it's an all too common occurrence within Marie's life. However, when the count draws his blade to defend his fiancée's honor, the matter quickly becomes one for the arena. Will a duel be what it takes to turn this political marriage into one of binding love?

Based on the popular light novel series that also inspired an anime!