The King Enternal Monarch is a 2020 romantic-fantasy South Korean television series starring Lee Min-ho, Kim Go-eun, Woo Do-hwan, Kim Kyung-nam, Jung Eun-chae and Lee Jung-jin. Set in two parallel worlds, the series follows Emperor Lee Gon of Kingdom of Corea, who discovers access to an alternate reality after crossing a mythical door opened by his half-uncle, Lee Lim, where Republic of Korea exists in the Kingdom’s stead and sets out to put an end to Lee Lim’s atrocities and retrieve the other half of Manpasikjeok used as a portal between two worlds.
Lee Gon (Lee Min-ho), a modern-day Emperor of the Kingdom of Corea, attempts to cross the barrier into an alternate reality where the Republic of Korea exists in the Kingdom’s stead. He comes across detective Jung Tae-eul (Kim Go-eun), whom he recognizes from an identity card he obtained during the turning point of his childhood: his father’s assassination.
Lee Gon’s half-uncle, Lee Lim (Lee Jung-jin), who assassinated the previous king, Lee Ho (Lee Gon’s father), is in hiding and assembling armies whilst traversing back and forth between the two parallel worlds.
Lee Gon: The third king of the Kingdom of Corea. He is a mathematician and a rower. He is a compulsive and reticent person. He is sensitive when touched by others and does not easily let go of his skepticism towards someone. He often leaves the palace grounds to wander around, either to tend to his curious mind or to escape the palace life. For him, the Royal Palace represents the safety of home, but it is also his most deadly battleground. When he was eight years old, he witnessed the assassination of his father by his half-uncle, Lee Lim. While he was being choked to death, he was saved by an unknown person with Jeong Tae-eul’s identity card.Lee Ji-hun: The Republic of Korea version of Lee Gon. He was killed by Lee Rim when he was a child. In the new timeline, he is seen to have graduated from the Korea Naval Academy.
- Kim Go-eun as Jeong Tae-eul / Luna / Koo Seo-gyeong
- Kim Si-woo as young Jeong Tae-eul
- Lee Ye-won as young Luna (Ep. 16)
Jeong Tae-eul: A police officer ranked Inspector (equivalent to Lieutenant in the Korean Armed Forces) in the Violent Crimes Squad Three of the National Police Agency of the Republic of Korea. She has a strong will and concrete personality. As a child, she was interested in crime TV shows which led her to become a detective.Luna: A criminal in the Kingdom of Corea. Shortly after her birth, she was abandoned in a slum in Busan. With no parents and no identification, no official records document her existence. As she grew older, her arrest record expanded to include burglary, breaking and entering, assault and forgery. Her imprisonment led to her being legally-documented as Luna, a name she gave herself after a stray cat that had survived in the slum. Moreover, she suffers from terminal cancer resulting in organ failure and has only few months left to live. In the new timeline, she is seen in 1994 Kingdom of Corea to be adopted by Koo Seo-ryung and her mother, giving her the adoptive name of Koo Seo-gyeong. She also later on becomes an Inspector in the Kingdom of Corea Police, just like Jeong Tae-eul.
- Woo Do-hwan as Jo Yeong / Jo Eun-sup
- Jung Si-yul as young Jo Yeong
Jo Yeong: Captain of the Royal Guard of the Kingdom of Corea, and childhood friend of Lee Gon. He exudes a sharp image and stoic professionalism. Jo Yeong first met Lee Gon at his coronation ceremony, when he was four years old. They share a bond of friendship and brotherhood. Jo Yeong treats Lee Gon as his country and his law, which he must always protect. In the new timeline, He still retains his position but with his new-born twin siblings, Eun-bi and Kka-bi.Jo Eun-sup: A member of the National Police Agency of the Republic of Korea, and the parallel universe counterpart of Jo Yeong. He is humorous, free-willed and joyous. Currently serving his mandatory military duties, his wish is to get discharged soon. He deeply cares for his younger twin siblings, Eun-bi and Kka-bi, and often helps his parents in looking after them. He also has a crush on his childhood friend, Myeong Na-ri. In the new timeline, he is seen as an agent of NIS