The 7th of the Seven School Mysteries. An apparition known as "Hanako-san of the Toilet." Specifically, he resides in the 3rd stall of the girls' bathroom on the 3rd floor of the old school building. Famous as an apparition who grants wishes in exchange for a price, he also plays the role of maintaining the balance between humans and apparitions. He looks like a young boy, but his actual age is unknown. He is always elusive and hard to pin down, but at his core, he is a very dangerous apparition. Usually flippant and childish, he often jokes around or teases others. However, he is actually quite quick-witted and has high situational judgment. While he shows emotion often, he has a habit of hiding his true feelings. He is reluctant to talk about himself and has a strong obsession with his past. Furthermore, he has a strong tendency to prioritize others over himself and easily takes on dangerous roles alone.

A first-year student at Kamome Academy High School. A human girl who made a contract with Hanako-kun. She has a constitution that makes it easy for her to see apparitions and is frequently involved in incidents related to the Seven Mysteries. Cheerful and expressive. She has a strong longing for romance and a slightly dreamy personality. However, she possesses a kindness that prevents her from leaving others in trouble. Though she is a coward, she will step into dangerous places for the sake of her friends. She is under a curse that makes her ankles look like daikon radishes. She has a very strong connection to the supernatural. She is deeply trusted by Hanako-kun. An existence that connects the human side and the apparition side. She is bound to Hanako-kun by a mermaid scale; if she enters water, the mermaid's curse turns her into a fish.

The second son of the Minamoto family. A boy from a clan of exorcists who banish apparitions. Initially, he intended to exorcise Hanako-kun. Serious and honest. He has a very strong sense of justice and prioritizes helping people. He is a hot-blooded type whose emotions show easily on his face. Exorcism arts. Attacks using lightning. Close-quarters combat. He used to view apparitions as "enemies," but his perspective begins to change as he interacts with Hanako-kun and the others. He starts to understand that apparitions also have emotions and circumstances.

The eldest son of the Minamoto family. A famous honor student within the school. A powerful exorcist. Usually calm and refreshing. However, he is extremely strict toward apparitions. He will exorcise them without mercy if necessary. Possesses strong rational thinking. High-level exorcism arts. Powerful lightning strikes. He prioritizes protecting humans above all else. Because of this, he tends to clash with Hanako-kun, who is on the apparition side. However, he is not purely evil and possesses his own sense of justice.

High-level exorcism arts. Powerful lightning strikes. Barriers. Sealing. Apparition detection. Characteristics: He prioritizes protecting humans above all else. Because of this, he tends to clash with Hanako-kun, who is on the apparition side. However, he is not purely evil and possesses his own sense of justice. Despite being on the human side, he has a deep understanding of the apparition world.