The Undying Mecha Emperor - Chapter 51 Dads

Welcome to Freia. A continent where evil magi ruled. Until firearms came, that is. Now the people live free of those demons…

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

In the eyes of outsiders, Hyuga Yuuto is a genius in the traditional sense of the Hyuga family:

Tough, strong, gentle, and calm, he is a partner worth relying on at all times.

However, no one knows, in countless silent nights.

The young genius of the separation family stroked the caged bird engraved on his head and fell asleep with the sharp needle in his mouth, fearing that in his sleep he would reveal the madness and anger deep in his heart——

“What Uchiha Itachi can do, I, Hinata Yuuto, can’t dare to do?”

- Description from novelbuddy

Originally born from a wealthy family, she ends up leading a vagrant life for fifteen years. However, when she is eventually found by her family, she falls into another devious plot and eventually dies tragically.