MTL - Non-famous Actor - ~ Sixteen, being misunderstood

Bai Aoxue, the best mercenary in the 21st century, is accidentally sent back to the Chengxi Dynasty in Great Continent due to an explosion in her mission, and trapped in the first daughter of Prime Minister. After her rebirth, she is set up by her father to marry the 5th prince Jun Yeyan who wears a mask all day long.
In the face of bloodthirsty enemies, discord between brothers, collusion among courtiers and invasion of enemy state, can Bai and Jun resolve the crises? What will happen to their political marriage? How will the fierce battle for the throne end?
With many twists and turns, the book brings you to experience palace revolution, love and hatred thousands of years ago.

- Description from Novelupdates

Tang Sect, the most famous martial arts sect of all. By stealing its most secret teachings to fulfill his dreams, Tang San committed an unforgivable crime. With his ambition attained, he hands his legacy to the sect and throws himself from the fearsome “Hell’s Peak”.

Born to a mother on death row and subsequently raised in the prison, Gu Tianyou did not have what most people would consider a ‘normal’ childhood. Instead of the usual math and history one might learn at a public school, he had criminals for tutors. He received regular lessons from notorious serial killer, Dr. Miao, and earned protection from the respected Master Long.

With such a unique background, Gu Tianyou graduated from the Police Academy with little difficulty, and was assigned as an undercover cop. But will the skills he learned from a lifetime of being cared for by criminals be enough to help him take criminals down?

After being imprisoned in the basement by her mother for ten years, she ended her cruel and tragic life in death when they forced her to hand over the key to the hidden treasure. Getting reborn in her teenage years, she woke up in the bed of that terrible and powerful man. This time, she must take revenge on her enemy, and now she must live.