The 4th Prince, son of King Taejo Wang Geon and Empress Yoo, and adopted son of the Shinju Kang clan. Despite being a prince with two powerful maternal families, he is notorious for being cruel and ruthless. He bears a large scar on the left side of his face caused by his biological mother, Empress Yoo, during his childhood, and always wears a mask to hide it. He is extremely reluctant to let anyone see his face and constantly yearns for his mother's love. He initially disliked Hae Soo for constantly talking back to him, but falls for her after she tells him not to ruin his long life over a small scar.

The 8th Prince, son of King Taejo Wang Geon and Empress Hwangbo. A talented man skilled in both literary and martial arts, he was born in the same year as Wang So but has a completely different personality. He possesses leadership skills, gathering people regardless of their status. While gentle and serious, his excessive ambition sometimes leads him to lose everything. He loves Hae Soo, who allowed him to show laughter and tears when he was always expected to be dignified. He was married to Lady Hae (Hae Soo's cousin), who helped him return to the palace after his exile, but after losing her to illness, he takes care of Hae Soo, determined not to lose her as well.

The 10th Prince, son of King Taejo Wang Geon. A mischievous boy who has no interest in martial arts or studies and only loves to play. He gets into a physical scuffle with Hae Soo after she catches him peeking at her servant, Chae-ryung. Following his brothers' teasing that Hae Soo might have acted that way because she likes him, he develops his first love for her.

The 14th Prince, son of King Taejo Wang Geon and Empress Yoo. With a bright and innocent personality, he receives all of Empress Yoo's love, earning Wang So's jealousy. He falls for Hae Soo after she risks her life to save him from having his arm cut off by thugs who held a grudge against his mother. He is a devoted man who only looks at one person without greed.

The 13th Prince, son of King Taejo Wang Geon. He is called Baek-ah because he shares the same name as the 8th Prince. Since his mother was from the Silla royal family, he is more observant of his surroundings than the other princes. He loved Lady Hae, his brother's wife and Hae Soo's cousin, but after her death, he becomes close friends with Hae Soo after spending a night drinking together.

Hae Soo's servant and the first friend Hae Soo made in Goryeo.