Misaki Yomiyama (読山 美咲, Yomiyama Misaki) was a student in Yomiyama North Middle School in 1972, along with Ritsuko Sakakibara, Kōichi Sakakibara's mother. He was in the 9th Grade Class 3-3. In the anime, Misaki is a major plot point, though he only appears in a photograph. In all versions of the story, he is the reason Class 3-3 was cursed, and the very first calamity started.

Misaki had the same appearance in both the anime and manga: short black hair and black eyes.

He wore the school's uniform from 1972. Due to the effect of the curse, his skin was deathly pale and covered in burns.

Misaki was a popular student since 7th grade: good at sports, intelligent, and good-looking. He had a great personality, being loved by all his classmates and teachers. His death shocked his classmates, who, in their grief, simply began to deny his death. While they had only the best of intentions, they inadvertently doomed several other students and their families to violent deaths, marking the beginning of the curse.

Misaki lived an ordinary life for a Japanese child of the 70s until his 9th-grade year. Placed in Class 3-3, he was a very popular boy both with his classmates and teachers. When he and his entire family died in a house fire, the entire community was shocked. One day, a student simply announced, "Misaki isn't dead. He's right there, in his desk." This sparked a chain reaction. Unable to deal with their grief, Class 3-3 simply refused to accept their loss, claiming Misaki was still alive and in class. This rapidly gained currency, and students began to "walk home" with Misaki, or address his desk as if he were still present, even going so far as to bring his desk to the class' graduation ceremony. However, much to the class' horror, Misaki really did come back, appearing in the class' graduation photo, smiling happily but deathly pale. Class 3-3 was never the same again.

Despite having the best intentions, the class had inadvertently brought class 3-3 closer to death. From that year on, every year the class had an Extra student...one who was no longer living, as wandering spirits latched onto the class for one last, brief chance at life. However, as this was unnatural, reality tried to compensate for the Extra student, and people connected to Class 3-3 (students, teachers, and their immediate families) began to suffer grisly deaths as the world tried to correct itself. This became known as the curse of Class 3-3, or more simply, the curse.

Though most people were aware Misaki was the origin of the curse, Misaki himself assumed the status of an urban legend, and by 1998, most students weren't sure of much about him. It was widely reported that he'd died in a plane crash with the rest of his family. In fact, by 1998, most of Class 3-3 thought Misaki was a girl, an association that didn't exactly help another Misaki in the class that year.

Unlike other spirits attracted by the curse, Misaki doesn't appear to be able to rest, forever stuck in Yomiyama. He appeared twice in the manga, once entering Ritsuko's room, causing her to blearily recognize him. Misaki replied with his name before vanishing. Misaki's final appearance in the manga was in the final chapter, walking around the school, suggesting he is still stuck on earth.