MTL - Rebirth 1999: Opening the Age of Black Technology - Chapter 843 ready

Yeon-woo had a twin brother who disappeared five years ago. One day, a pocket watch left by his brother returned to his possession. Inside, he found a hidden diary in which was recorded “By the time you hear this, I guess I will be already dead….”

In the Tranquil Sun province of the empire, there exists an unremarkable lordship known as Xue Ying Territory! This is the home of the Dong Bo clan, the clan of our hero Xue Ying!

His father, a commoner turned noble; his mother, a noble who abandoned her clan for love, and his brother, an innocent toddler. But peace cannot last forever, Xue Ying’s peaceful life is shattered, and the only way to reclaim it is through power!

- Description from novelupdates

Seven years ago, after their breakup, he disappeared without a trace.