A famous exorcist in Haegwang City. She performs exorcisms for money and is very money-oriented. An old friend of Soohyun. When she eats sweets, she cannot see ghosts. She travels with Chageun. She exorcises ghosts using special clothes that protect her and the Moonlight Sword, a blade inherited from her grandfather.

The guardian spirit of Haegwang City. However, because a Yagoe stole his power, he has been reduced to a tiny turtle unable to use any abilities. He is the owner of the training ground where Sleepground practices and has offered her a large sum of money to help him reclaim his power.

Deokgae's classmate. He is very good at studying. He suffers because of his friend Deokgae, who is obsessed with the exorcist Sleepground. Even though he was once possessed by a ghost, he does not believe in them.

A huge fan of Sleepground. He gets ecstatic the moment he hears Soohyun is friends with her, and gushes to Sudam about how cool she looks while exorcising. He snaps at classmates who suggest Sleepground is a 'has-been' exorcist. He is in the same class as Sudam and Guest. For some reason, he is the class president.

An old friend of Sleepground. He is a photographer by profession and reunited with Sleepground while she was exorcising a Yagoe. Since then, he has acted as a bridge, introducing Sudam and Deokgae to her and helping her track down various Yagoes. He is Deokgae's older cousin.

He was more popular than Sleepground when he first appeared because his prices were cheap and he even performed free exorcisms for those lacking funds. He wears a white suit and exorcises using a custom-made gun. He makes sarcastic remarks to Sleepground, asking why she wears such cumbersome clothes or who uses swords for exorcism these days. He is Donghee's father. He hates Chageun, believing Donghee died because of him. The final antagonist.

A ghost owl. Because of this, he becomes invisible to Sleepground when she eats sweets. He is a friend and assistant who helps Sleepground; they first met while saving children in a cold storage warehouse. He nags constantly, which often annoys Sleepground. He is Donghee's uncle. He saved Sleepground instead of Donghee, earning Gongryong's hatred. He carries deep guilt.