Yoosung

Formerly a slave, Yoosung's father wished to give his children a higher station in life.

He settled in the downstream region of the river and earned the right to escape serfdom by serving in the military against frequent foreign invaders. However, only a few years later, his entire family was slaughtered by the invaders, with Yoosung being the sole survivor.

General Gwak took the young Yoosung under his wings, allowing him to learn martial arts at the general's camp and grow into an outstanding military officer. Though he is quiet and difficult to read since he rarely expresses his inner thoughts, Yoosung is fond of So-hee and spends a significant sum of money to bestow a favor on the young kisaeng Iseul.

(Source: the manhwa's character introductions)