Vows and Vendettas

Story

After a prophetic dream foretells her sister’s death in a political marriage, Arasilla Hugo takes matters into her own hands and marries in her place. Her groom? Demian Vandermeer, the knights’ captain and the brother of her sister’s former betrothed. The only problem is that mages and knights are sworn enemies, and their sharp tongues and stubborn hearts turn every situation into a competition. Arasilla races to save her sister from a tragic fate, while Demian fights for the dukedom. Will their rivalry stay just that? Or will their contractual marriage burn into something more?

Synopsis via AniList (English).