Read the Profile of Characters in the Drama 'The King: Eternal Monarch' Before Watching, Lee Min Ho Becomes Emperor and Kim Go Eun Portrays Two Women from Different Worlds

Lee Gon (Lee Min Ho) is the third-generation emperor of Korea, known for being cool, handsome, calm, and having perfect rules, but he is also quiet, sensitive, compulsive, and dislikes being touched. He feels that the kingdom is both the safest and most dangerous place when he sees his father's assassination plan. Lee Gon has no plans for marriage and often runs away from the kingdom.

Kim Go Eun portrays the characters Jung Tae Eul and Luna. Jung Tae Eul has wanted to become a police officer since she was a child. After successfully overcoming her own weaknesses, she has been a detective for six years and believes she can defeat all criminals. Her life starts to become confusing when she suddenly meets an emperor who claims to be from a parallel world.

Kim Go Eun also portrays the character Luna, a criminal from the impoverished area in Lee Gon's home country. She has no family or identity in the government and has to survive on her own. The world only becomes aware of her existence after she is captured. However, Luna is known to have cancer and only has three months left to live.

Woo Doo Hwan also portrays a dual character. First as Jo Eun Seob in Jung Tae Eul's world. Eun Seob is a public servant who works for the police. He had to drop out of college when his mother gave birth to twins and he had to take care of his two younger siblings. Eun Seob had an accident that caused him to fail his studies again and immediately join the mandatory military service. When he is about to finish his military service, he meets Lee Gon.

Another character played by Woo Doo Hwan is Jo Young, Lee Gon's bodyguard, who is skilled in all types of weapons. Jo Young has known Lee Gon since the age of four and has promised to always make the emperor happy. Jo Young is also the only person who knows when Lee Gon laughs or cries.

Kang Shin Jae (Kim Kyung Nam) is a detective and Jung Tae Eul's co-worker. He is fair, stubborn, and considers the police officers as his family. He is curious whether Tae Eul sees him as more than just a co-worker.

Gu Seo Ryeung (Jung Eun Chae) is the youngest and only female Prime Minister in Lee Gon's country. She is ambitious and will do anything to gain power. She even uses divorce to gain votes in the election. Seo Ryung takes advantage of Lee Gon, as she receives full support whenever she is near the emperor. Because of this, she falls in love with the emperor and becomes extremely jealous when she feels that Lee Gon likes another woman.

Lee Rim (Lee Jung Jin) is Lee Gon's uncle who conspires against the emperor's father.

Noh Ok Nam (Kim Young Ok), an old woman who has been taking care of Lee Gon since he lost his parents at the age of 8.

Jung Do In (Jeon Bae Soo) is Jung Tae Eul's father who is also a taekwondo coach for his daughter. He has raised her alone since his wife passed away from cancer.

Song Ju Hye (Seo Jeong Yeon) is a person who does many strange jobs, until she realizes that her entire family has changed.

Park Moon Shik (Park Won Sang), the leader of the detective team, including Jung Tae Eul. He is a hardworking person.

Myeong Na Ri (Kim Yong Ji) is the owner of the building where Jung Do In used to train taekwondo, and she is also a schoolmate of Jung Tae Eul.

Kim Yong Ji also portrays the character Myeong Seung Ah, who is an employee at the Lee Gon kingdom responsible for managing social media accounts and websites, and has skills in writing official statements, filing legal complaints against harsh comments, and photoshopping.