Monsters and other harmful creatures or people causing problems for the various Protagonists.
Click here to visit Yomi, the ghostly narrator of the series.
Reiko was killed the summer before her graduation year of elementary school, when she was shoved to the ground and her head hit a rock, then her body was disposed of by the school incinerator. Her charred spirit sought revenge against the girl responsible for it the following year.
A vengeful, scary spirit of a betrayed young woman whose boyfriend left her to be with her backstabbing friend. Out of spike and heartbreak she committed suicide on her bed, and now her ghost haunts girls indiscriminately in search of traitors. But it's said she will kill any girl whose bed she finds herself under.
Saya was a black cat hit and left to die by Ayako and her family on their way home one evening. While her parents had planned on checking the cat, Ayako convinced them to leave. After being reborn as a kitten, Saya she sought the family out and with her newfound magic, she began torturing Ayako before killing her, then she went on to take her identity and eventually began eating people.
An urban legend who is said to approach others and ask them if she is beautiful; if they say yes she will reveal her face to them and ask again- but if they say no or try to run away, she will kill them. Miya Maeshima indirectly caused her rebirth after her mean-spirited pranks resorted in her girl classmates violently beating up their substitute teacher. At her limit, Natsuko Akamiya snapped and has since donned this identity.
A young man with a crush on Sakura Moeno, when she spurned him and made fun of him, he committed suicide and his blood was baked into cream puffs later delivered to her. After eating them, Sakura began to feel sick and he eventually confronted her, revealing his spirit to now be inside of her. He stabbed her from the inside.
Like Misa Tamura, they went on frequent rampages on their school's anonymous forum and had been found dead in unusual ways that seemingly came out of nowhere. They gang up on Misa and torment her for a few days before killing her, turning her into one of them. Then they repeat the process by choosing a new target.
One day in swim class, Nana overhears some girls discussing a legend of their school. Some years back a girl vanished, and it's believed that her beauty was acknowledge by a mermaid and she was taken to their world, then when she returned she went on to become a model. As Nana tried to see a mermaid for herself, not only was Yuina taken, but also her friends, and her friend Hatsuki.
She eventually discovers that the "mermaids" are nothing more than a withered chain of corpses of girls dragged beneath the waters surface. The one on top targets a girl she deems prettier than herself and adds her to the chain.
A mysterious woman who is said to grant the wish of those who earnestly clean a specific toilet of a girls restroom at Suzu Oono's school. The story surrounding her involves a plain girl who went into the stall one day and came out gorgeous, and Suzu learns that the girl didn't change appearance- rather, the girl within the toilet pulled her inside and took her place, which she then does to Suzu.
Kasako was a young girl killed in a traffic incident back in 1999, when she was out searching for her umbrella that some bullies hid. Now she shows up on rainy days carrying what looks like an umbrella but is really her severed arm, and she tells whoever finds her to locate her umbrella in four days. If the person refuses or fails, she severs their arm and kills them.
The nightmarish spirit of a little girl who forces others into horrendous games of tag in their dreams. Hiroko was a classmate of Chika Nishizono and her friends and after being mercilessly made fun of for her small stature and slow running speed, she began to practice by running to and from school. But one day she failed to see an oncoming vehicle and was killed, and she has since been in a coma.
- Saya is the only known animal Antagonist in the series.
- Akamiya is the only living human Antagonist, as she did not die from her experience.
- Misa is the only Protagonist to have become a monster in the series.