Male, Gucheon.

He lived in a temple before being kidnapped by the King. The reason he lived at the temple was that the nearby river was the place where his mother passed away.

His mother had spiritual powers and was a shaman. However, when she became pregnant with a child (Gucheon), the god she served was enraged and cast a curse. Eventually, the mother, suffering from the curse, fell into the river with Gucheon.

But Gucheon was the only one who survived.

Despite being underwater for over fifteen minutes, he survived and was taken in by the temple. Since then, he has seen all sorts of ghosts and spirits, learning how to deal with them.

After being kidnapped by the King, he received a life-threatening threat/command to forcibly eliminate the ghosts of the Eastern Palace. Formally, he is a geomancer who came by royal decree. He doesn't know a thing about geomancy.

Female, Saenggang.

The younger sister of the Crown Prince Ghost and the daughter of the King. However, she was exiled from the palace with her mother.

The reason for the exile? Well, because she knew the 'secrets of the palace.'

Like her brother, the Crown Prince Ghost (when he was alive), she can sense ghosts through sound. That is why His Majesty placed her next to Gucheon for surveillance. ...Though it seems that wasn't the original purpose.

Male, King.

Everyone else addresses him politely as 'Your Majesty.' He kidnapped Gucheon to protect his son, Prince Yeongan, from the Pond Ghost. In truth, he only cares about Prince Yeongan's life and doesn't care about Gucheon's life at all. Therefore, he does not let Gucheon leave the palace for fear he might escape.

The Crown Prince Ghost, Saenggang, and Prince Yeongan are all his biological children.

A Gwimae spirit, Kkeomeoksalai.

It is a spirit that lives bound to a person rather than a place. Spirits are originally created from the sinister energy of nature or the negative power of humans.

It doesn't really make any sound, so Saenggang cannot perceive it, but Gucheon, who identifies ghosts by sight...

...Yes, well, that's how it is. Got it? (?)

Male ghost, Crown Prince.

He is the ghost with the greatest grudge in the palace. Because of this, he is the strongest ghost in the palace, and his grudge stems from the fact that he could not become King. Before the Crown Prince could become King, he was poisoned by the toxin fed to him by his father (the King). And before dying, he dies saying he will become the 'true Pond Ghost.'

Female ghost, Seungeun Sanggung.

In the past, when the last favored court lady became the first to carry the previous King's child, the Queen Dowager, who was the Queen at the time, framed her and caused a miscarriage.

"I shall dry up the seeds of the Eastern Palace!" Shouting this, the last favored court lady jumped into the pond. Becoming a ghost, she rooted her grudge in the pond.

Female ghosts, palace maids (said to be 13 in total).

「The snake's skin killed the dragon's hatchling」 Using this writing as a pretext, the palace maids were locked in the salt warehouse and burned to death.

The one who set fire to the salt warehouse was the Queen Dowager, who was born in the year of the snake. (In the Donggung series, a battle with Gucheon takes place in front of the Queen Dowager's Buddha statue... I forget which episode it was) The dragon's hatchling referred to the Crown Prince, and she burned the maids to death fearing the blame would fall on her.

She coarsely ground the bones from the corpses of the dead maids, put them in a jar, and sealed them in the salt warehouse with talismans and ropes (a precaution to prevent the grudge from threatening the royal family).

The seal, which should not have been broken, was broken by someone.