He has the ability to enter the spirit world. He usually does this by hanging a rope around his neck and jumping into a pond; he enters that realm by technically dying. Originally a low-born monk from a temple, he was brought to the palace by the King after rumors spread of his ability to see and exorcise ghosts. He is currently disguised as a geomancer. The King has threatened to kill him if he fails to save Prince Yeongan. He quickly realizes Saenggang's true identity and finds himself unable to be harsh with her. He is an expert on ghosts. He lived in a temple because his mother drowned in a river when he was a child. He usually addresses Saenggang as 'Princess,' but calls her by name when she is in danger. Despite the vast difference in their social status, he doesn't hesitate to touch or protect her when her life is at stake.

A spirit parasite that clings to living people and sucks away their life energy. It looks quite cute and doesn't usually harm people, but it occasionally transforms into a massive, powerful form.

The King's son. He was forced to drink poison and killed by his own father because he knew the King's secrets. He is now the most powerful and vengeful evil spirit, determined to sever the entire royal bloodline.

The Princess's grandmother and the King's mother. She harbors deep secrets. She is a woman who prioritizes her own interests above all else. She is the only person Saenggang truly trusts and relies on in the palace, and the two share a deep, mutual bond of support.

Saenggang's father. He is a man of many secrets who will do anything to protect his throne. Although he cares for Saenggang, he is often cold and grumpy toward her. He dislikes Gucheon but allows him to live, knowing that Gucheon is Saenggang's only source of comfort.