The East Palace

Also known as: Gu-cheon, Spirit Slayer, Ghost Slayer, Buddhist Spirit Slayer

Gu Cheon is an irreverent spirit slayer who can cross between the living world and the Realm of Gwi and cut down hostile spirits. Haunted by guilt surrounding his mother's death, he initially avoids responsibility and resents being forced into royal service. His partnership with Saeng Gang gradually gives him a reason to protect others despite the supernatural cost.

Also known as: Saeng-gang, Court Lady Saeng Gang, Hidden Princess

Saeng Gang is a court lady born with the ability to hear the voices of the dead. She is secretly King Ju Sang's daughter and is assigned to guide and observe Gu Cheon during the curse investigation. The search for the truth forces her to confront her mother's death, her concealed royal identity, and the crimes committed by her own family.

Also known as: The King, His Majesty, Ju Sang

King Ju Sang rules the kingdom while the deaths of his sons threaten both his family and his throne. He secretly recruits Gu Cheon and Saeng Gang to investigate the East Palace, but withholds his own connection to the Crown Prince's death. His attempts to preserve royal authority repeatedly create new resentment and supernatural consequences.

Also known as: The Crown Prince, Late Crown Prince, Crown Prince Spirit, Ak-Gwi

The Crown Prince is King Ju Sang's deceased son and former heir, whose apparent suicide begins the present-day investigation. Before his death, his ruthless pursuit of the throne placed his own brothers in danger. His resentment survives as a powerful ak-gwi and becomes the central supernatural threat to the royal bloodline.

Also known as: Her Royal Highness the Queen Dowager, Former Queen

The Queen Dowager is the senior royal elder who remembers the first wave of princely deaths thirty years earlier. She promotes the belief that the Favored Court Lady's spirit is responsible and brings a male shaman into the palace. Her jealousy, political influence, and suppression of the old scandal make her a major source of the palace's generational resentment.

Also known as: Consort Sukbin, Suk Bin Choi, Lady Choi, Saeng Gang's Grandmother

Choi Suk Bin is King Ju Sang's biological mother and Saeng Gang's paternal grandmother. She presents herself as a protective family elder while guarding the truth about how her son survived the earlier succession crisis. Her ambition and the murders committed to establish her bloodline are central to the human origin of the palace tragedy.

Also known as: Prince Ik-Sang, Ik Sang-gun, Collateral Royal Prince

Ik Sang is a collateral royal prince who sees opportunity in the collapse of the King's immediate succession line. He secretly employs Park Su to worsen the supernatural crisis while promoting his own son, Prince Inha, as the alternative heir. His ambitions place him in political conflict with the King and eventually expose him to investigation.

Also known as: Park-Soo, Shaman Park-Soo, Male Shaman, Palace Shaman

Park Su is the male shaman brought into the palace through the Queen Dowager's household. He is secretly Ik Sang's operative and uses spirits to weaken the King's heirs rather than resolve the curse. He later accepts power from the Crown Prince's ak-gwi, attacks Gu Cheon, and becomes a liability to the political conspiracy he serves.

Also known as: Yeongan, Prince Yeon Gan, Prince Yeon-gan

Prince Yeongan is King Ju Sang's youngest and initially last surviving son. His possession and declining health force the king to recruit Gu Cheon and begin the secret investigation. Although he temporarily recovers after the pond spirit is released, his later death proves that the investigators have not found the true threat.

Also known as: Seungeun Sanggung, Pond Spirit, Favored Palace Woman

The Favored Court Lady was a palace woman who became pregnant by the previous king and was falsely accused of an affair with a Royal Guard. The persecution, loss of her child, and unjust death leave her as the resentful spirit associated with the East Palace Pond. She is dangerous but ultimately a tragic victim and a false lead rather than the force responsible for every royal death.

Also known as: Saeng Gang's Mother, Royal Consort Han, Lady Han

Royal Concubine Han is Saeng Gang's mother and one of the women drawn into Choi Suk Bin's succession conspiracy. She is forced to assist with the earlier poisonings and later becomes King Ju Sang's concubine. After leaving the palace to protect Saeng Gang, she is silenced before she can expose what she knows.

Also known as: Inha, Prince In-ha, Alternative Heir

Prince Inha is Ik Sang's son and becomes the leading alternative heir after the King's sons die. The Queen Dowager elevates him into increasingly visible royal duties while his father exploits the curse to improve his succession prospects. His unexplained illness becomes evidence in the struggle over whether the palace danger comes from human poison, supernatural attack, or both.

Also known as: Kim Sang-seon, Chief Eunuch Kim, Sangseon Kim

Kim Sang Seon is the King's trusted chief eunuch and one of the few palace attendants allowed close to the secret investigation. He carries confidential orders, controls sensitive access, and intervenes when rival factions attempt to eliminate Gu Cheon. His consistent loyalty makes him the operational link between the King and the investigators.

Also known as: Senior Court Lady Jang, Court Lady Jang

Lady Jang is a senior court woman who serves the Queen Dowager and carries out her confidential orders. She knows crucial details about the Favored Court Lady's persecution and the cover-up surrounding the old palace deaths. Gu Cheon and Saeng Gang pressure her into becoming a reluctant witness against the secrets she spent years protecting.

Also known as: The Guard, Guard's Ghost, Coerced Confessor

The Royal Guard was forced to confess falsely to an affair with the Favored Court Lady after the Queen Dowager threatened his family. His testimony helped destroy an innocent woman and left him carrying guilt after death. As a ghost, he provides evidence that allows Gu Cheon and Saeng Gang to reconstruct the original palace scandal.

Also known as: Gu Cheon's Mother, Possessed Mother

Gu Cheon's mother dies during the childhood tragedy that awakens his connection to the spirit world. Gu Cheon spends years believing that he caused her death, shaping his isolation and refusal to help others. The truth that possession influenced the incident becomes essential to his ability to resist becoming an ak-gwi.

Also known as: The Queen, Queen Consort

The Queen Consort is King Ju Sang's wife and the senior consort of the reigning royal household. She is caught inside the succession crisis as the king's sons die and competing branches seek control of the throne. The drama gives limited independent detail about her personal ambitions or history.

Also known as: Ji-yul, Court Lady Ji Yul

Ji Yul is a palace attendant and trusted companion within Saeng Gang's immediate circle. She cares for Saeng Gang during illness and alerts Gu Cheon when Saeng Gang disappears, behaves strangely, or appears to be in supernatural danger. Her role is supportive, and little is established about her life outside Saeng Gang's service.

Also known as: Gu Cheon's Mentor, Elder Monk, Buddhist Monk

The Monk is an elderly spiritual practitioner who previously helped the palace during the first outbreak of supernatural deaths. Unable to return himself, he identifies Gu Cheon as the person capable of entering the Realm of Gwi and fighting the renewed curse. His recommendation directly causes Gu Cheon's recruitment.

Also known as: Royal Consort Yoon, Lady Yoon

Royal Concubine Yoon is a member of King Ju Sang's inner royal household. Available cast listings confirm her presence but do not provide enough reliable information to define her family connections, motivation, or independent story arc. She should remain a supporting record pending direct episode review.