The first-ranked of the school youkai, the Headmaster is far more powerful than any other known youkai. The Headmaster is the only youkai capable of erasing humans from existence.
The second-ranked of the school youkai sometimes referred to as the Vice Principal. Izanami has the power to lure humans into alternate worlds devoid of other humans wherein they have to continuously run away from Izanami.
The fifth-ranked of the school youkai and guardian of the "mirror world." Kyou has the power to move between different worlds at will through the use of mirrors.
The sixth-ranked of the school youkai and guardian of the art room. Renoir hunts by luring humans into paintings within the art room, trapping them within gruesome situations.
The seventh-ranked of the school youkai. Sumire is initially the weakest of the school youkai and hunts predominantly by disguising herself as a weak young girl. She incites others to bully her and her tears cause her onlookers to be overwhelmed with a desire to bully others. Sumire then feasts on the fading souls of those who are bullied.
The eighth-ranked of the school youkai. Mesomeso was originally a human known as Marie Moriya until she has murdered by her teacher. If one hears Mesomeso's cries beyond a door, they cannot open the door or respond to anything she says. If they do, Mesomeso will become a fearsome monster that will crush every bone in their body. Even Higanbana is deterred from opening a door due to Mesomeso's power.
An unranked yet powerful youkai and the Headmaster's right hand. The Black Tea Gentleman is sometimes referred to as the "Shadow Vice Principal." Due to their similar positions and opposing views on how humans should cope with hardship, the Black Tea Gentleman and Izanami are often at odds. The Black Tea Gentleman allows humans the ability to thoroughly believe lies, thus allowing them to live out their dreams within their own minds.
A relatively new youkai who lacks an established legend. Hameln desires to create the legend of "Hameln of the music room" by using his castanets to turn humans into small animals and then luring them to their deaths.
A powerful youkai from the mirror world otherwise known simply as Geragera. She is the mirror world equivalent of Mesomeso and is the first-ranked school youkai of the mirror world. When she crosses into the normal world, Geragera demonstrates the ability to easily defeat strong youkai such as Higanbana though she is eventually banished back to the mirror world.
A bullied girl at the school. The only friend Marie manages to make is her teacher, Yoshihito Kanamori, however he quickly uses his position to sexually exploit Marie. As his power over Marie wanes, Kanamori kills Marie. After her death, Marie returns in the form of a youkai known as Mesomeso.
A young boy obsessed with the truth after being falsely accused of breaking an anatomy dummy. His desire for the truth manifests in the form of a love for photography.
A popular girl who falsely accuses Takeshi Nonomiya of breaking an anatomy dummy. She is subsequently driven to suicide by Takeshi's unrelenting stalking.
A girl with a deep love for theater. Midori aspires to have the lead role in a school play and is willing to make a deal with a youkai in order to achieve this.
An outcast who claims to have a sixth sense that gives her access to the spirit world. Michiru demonstrates an ability to speak to some youkai such as Mesomeso and Sakunoshin. However, she remains unable to make any friends other than a similar outcast, Tomoko Okada.
An aggressive boy who initially is quite derisive to several of his classmates. After they begin to bully him by treating him the same way he treated them, he decides to take his revenge by making a deal with a youkai.
A headstrong girl who initially is the victim of heavy bullying. After her entire class is killed in a bus accident, Sakaki decides to never allow bullying and makes an effort to stop it whenever she can.
An abused girl who seems to draw the attention of every bully. She later turns out to actually be the youkai Sumire who hunts by inciting others to bully her.
A young boy who is abused by Nafumi Shintani. He maintains that he loves Shintani despite her extensive abuse. He is accidentally killed by being crushed under a plaster bust.
A young girl obsessed with the occult and Michiru Sakurada's only friend. The two often spend time poring over documents and having lengthy conversations on the occult and the supernatural.
A boy who becomes the victim of extensive bullying. He makes a deal with a youkai in order to become a bully himself. He maintains a victim complex that he uses to justify bullying his classmates.
An abusive teacher at the school. Kanamori uses his position to sexually abuse Marie Moriya. When he learns that his power over Marie is fading, Kanamori kills her out of desperation and dumps her body in a septic tank. Shortly after, Marie returns in the form of a youkai and kills Kanamori.
A teacher who sexually abuses several young boys at the school. She often takes the boys into the art room and has them strip so that she can draw them nude. She often abuses these boys by burning them with cigarettes and cutting them with a palette knife.