MTL - I Was a Top Student In Conan, But I Was Actually An Onmyoji - Chapter 200

In the foreign world, the martial artists dominate the world and the sword of the emperor controls the fate of hundreds of millions of lives! Long Yu, the number one killer on Earth, after dying, takes rebirth in this new world in an aristocratic family of martial artists but faces rejection because he is unable to practice martial arts.

What would you do if you could control and use your Karma?

Because her appearance was not breathtaking, the Emperor breaks off their engagement and bestows her instead to the bloodthirsty, ruthless, and cold-blooded Second Prince (Wang Ye).

On her wedding night comes endless humiliation, the genuine Princess Consort becoming a deserted women. A foolish woman before rebirth, she no longer expects his love. In this world, she must possess enough talent to awe those around her, carrying herself with composure and articulating with beautiful diction, override above the nine night.

- Description from Novelupdates