Perfect Crown

Also known as: Sung Hui-ju, Sung Hee-ju, Seong Hee-joo

Seong Hui Ju is the CEO of Castle Beauty and the illegitimate second daughter of Castle Group chairman Seong Hyeon Guk. Brilliant, ruthless, and fiercely competitive, she resents the noble class for looking down on her commoner and illegitimate status despite her wealth and success. She proposes a contract marriage to Grand Prince Yi An as a calculated move to secure unbreakable social legitimacy. Her arc follows the shift from a purely transactional alliance into genuine romance and self-acceptance.

Also known as: Prince I-an, Lee Wan, I-AN

Grand Prince Yi An is the second son of the late King Hui Jong and younger brother of the late King I Hwan, serving as regent for his young nephew, King I Yun. Raised to be quiet and obedient, he suppresses a passionate, fiery temperament and hidden ambitions for the throne beneath royal decorum. He is watched closely by Queen Dowager Yun I Rang and pressured into a strategic marriage meant to neutralize his influence. Meeting Seong Hui Ju through a contract marriage becomes the turning point that lets him pursue real freedom and connection.

Also known as: Min Jeong-woo

Min Jeong U is the Prime Minister and eldest son of a multi-generational political family, following his father and grandfather into the office. He is Grand Prince Yi An's closest friend and confidant from their Royal Academy days, well-versed in palace politics. His composed exterior hides deeper feelings for Seong Hui Ju, and his loyalty to Yi An is tested once the prince's marriage to her is announced.

Also known as: Yoon Yi-rang, Queen Dowager, Queen Mother

Yun I Rang is the Queen Dowager, widow of the late King I Hwan and mother of the young reigning King I Yun. Daughter of Yun Seong Won, head of the influential Yun family that has produced four queens, she was raised to embody royal grace and decorum. She once had feelings for Yi An during their Royal Academy years but married his brother instead, turning that history into lasting tension. She now views Yi An as a threat to her son's throne and pushes for his marriage as a way to neutralize him.

Also known as: Choi Hyun

Choi Hyeon is Grand Prince Yi An's aide, serving publicly as his assistant and privately as a loyal, trusted right-hand man. He is the only staff member Yi An kept after dismissing his royal security, and he brings a warm, grounded, slightly comedic presence to the prince's inner circle.

Also known as: Do Hye-jeong

Do Hye Jeong is Seong Hui Ju's chief secretary at Castle Beauty, managing her schedule and affairs. Reliable and fiery in her own right, she frequently clashes with her demanding boss while remaining a trusted presence at her side.

Also known as: Seong Tae-joo, Sung Tae-joo

Seong Tae Ju is the eldest son of Castle Group and Seong Hui Ju's older half-brother through a different mother. As the legitimate child married into a noble family, he is positioned as the 'safe' choice to succeed their father, though he lacks his sister's killer instinct and consistently comes up second to her in the business world.

Also known as: Buwongun

Yun Seong Won is the patriarch of the prestigious Yun clan and the father of Queen Dowager Yun I Rang, making him grandfather to the young King I Yun. He presents himself publicly as progressive and supportive of equality, but is privately a staunch classist determined to preserve noble privilege as the old social hierarchy erodes. He firmly opposes Grand Prince Yi An's choice to marry Seong Hui Ju, viewing her common and illegitimate status as an unacceptable stain on the royal line.

Also known as: Seong Yeong-guk, Cho Seung-yeon's character

Seong Hyeon Guk is the Chairman of Castle Group, the country's top conglomerate, which he built through ruthless business tactics. He is the father of both Seong Tae Ju and Seong Hui Ju by different mothers, and the inheritance conflict between his children drives much of the corporate side of the story.

Also known as: Choi Jin-suk

Choi Jin Suk is a court lady of Anhwa Hall who arrives in the story to train Seong Hui Ju in royal etiquette and protocol ahead of her marriage into the royal family. She is destined to serve in the royal household once Grand Prince Yi An ascends the throne.

Also known as: Han Da-young

Han Da Yeong is the wife of Seong Tae Ju and daughter-in-law of Chairman Seong Hyeon Guk, making her Seong Hui Ju's sister-in-law. She is the eldest daughter of the former Minister of Justice, coming from a prominent legal family.

Also known as: Lee Ae-rum, Lee Aerum

Lee A Reum is a servant on staff at Grand Prince Yi An's private residence. Beneath her ordinary role, she is secretly a mole working for the Queen Dowager, feeding information about Yi An's household to the palace faction opposing him.

Also known as: Kim Young-sun

Kim Yeong Seon is the primary manager of Grand Prince Yi An's private residence and the younger sibling of Kim Yeong Mun. Confident and charismatic, she maintains a friendly rapport with Yi An, preferring the more relaxed rules of a private household over the strict regulations of the main royal palace.

Also known as: Park Seung-hee

Park Seung Hui is a staff member at Castle Beauty, Seong Hui Ju's company. Limited detail is available about her specific duties or storyline involvement.

Kim Yeong Mun is referenced in source material only as the older sibling of Kim Yeong Seon, a staff member within Grand Prince Yi An's private residence household. No further confirmed details on this character's role or personality were found.