Hong Gildong
This second-born prince does not get along with his father, but to the extent that his father's exorbitant wealth gives him advantages, he uses them wisely. He has unparalleled martial arts abilities, and his psychic enlightenment has given him access to magic. He spends his young days leading a gang of thieves who steal only from the wealthy and give the money to the poor. After he leaves that area, he deposes a king of his throne and makes himself into the king of Yul. The Yul folks really like him.
Hong Mo, the prime minister
This high official conceived a son with his concubine on the night the prime minister had an portentous dream. He is Hong Gildong's second-born son, and their relationship is defined by their on-going dispute about whether Hong Mo should spoil and prefer his first-born son over Hong Gildong.
The Hwalbindang gang
This band of robbers steals from the wealthy and gives to the poor. When they get removed from their territory by the king, Gildong starts a new gang by the same name in the region of Yul. The Hwalbindang is not dissimilar to Robin Hood's gang.
The king of Yul
When Hong Gildong arrives in a territory where the people seem to be oppressed by the king of Yul, this character, Hong confronts him in an attempt to depose him from his throne. The king of Yul fights back, but he is killed and replaced by Gildong.