|“||...the only way to stop the calamity is: send the dead back to death.||”|
|Age||29 - 30|
Katsumi Matsunaga is a Yomiyama North Middle School student from the 3-3 class of 1983 along with Reiko Mikami and Ryoko Akiyama. During 1983, he managed to successfully stop the calamity in class 3-3; the only recorded case of the phenomenon stopping halfway through the year.
In 1983, Mr. Koga, the homeroom teachers of class 3-3, organized a trip for 2 days and 3 nights at Yomiyama Shrine. Then restoring the Abandon Yomiyama Shrine to its original shrine and praying to remove the curse. After praying at the shrine, Mr. Koga declared everything would be okay and the class is free of the curse. After leaving, the sky turns overcast, and it begins to rain, everyone leaves the shrine and Matsunaga is walking behind Hamaguchi and witnesses his death. After this, he has a fight with a classmate in the forest. They begin to argue so badly that Matsunaga gives him a punch and accidentally knocks him down, piercing his head on a tree branch, killing him. Katsumi, terrified, runs away until he is questioned by the police who arrive at the scene. The next day, he returns but the body has disappeared. When he asked his classmates about the classmate (his name can't be heard because the tape was altered by the calamity), no one remembers him. Katsumi realized that he killed the extra one. Afraid he would forget his findings, he recorded his theories and confession on a tape for the following years' students to find and hides it in a classroom. But in time, even Katsumi forgets what happened on the class trip. After graduation, he moved to Tokyo to pursue his studies. He became a banker but dropped out after a few years, and returned to Yomiyama to help with the family business. He actually works and lives in a hotel.
He has brown hair, brown eyes and a negligent appearance. He is seen wearing an outfit which consists of a pale blue T-shirt, a dark blue shirt, a pair of pale pants and dark blue shoes.
In the live action film, he appears briefly, when Kouichi and Mei interview him about his year's Calamity. He wears the uniform of a hotel valet, and most notably, he's missing the fingers from one his hands, a wound he self-inflicted for killing a classmate.
Katsumi seemed an ironic and superficial person. When he comes out about the 9th Grade Class 3 curse he turns out to be agitated and stressed.
He made his debut in "Sphere Joint" in Tomoka's flashback.
In "Hair Stand", after he learns that Reiko looked for him at the beach hotel, he went out to look for them. On the shore, Matsunaga had a chat with Reiko and the others; he and Reiko both comment how long it's been since they've seen each other, and Katsumi tells his old friend she hasn't changed much since Middle School. However, the fun at the beach is cut tragically short by Junta Nakao's death, despite the group's efforts to save him. Shocked out of his post-traumatic stress disorder, Katsumi remembered the tape's location.
At the beginning of "Glass Eye", Kouichi, Naoya, Yuuya, and Mei listened to the repaired tape, and learned how to end the Calamity: Send the Dead back to Death. Yuuya later shared the tape with Izumi and Takako, which unfortunately caused more problems than it solved and led to most of 1998's curse related deaths.
- In the original novel, Matsunaga is never seen and only has contact with Tomoka Mochizuki. Also, she claimed that he is a faithful client at Inoya Cafe.
- He is a smoker and drinker.
- He was deeply affected by Junta's death, remarking in disbelief that last time he'd protected them.
- His first name means "overcome," or "serpent."
- The closing words of his tape, "Send the dead back to death" are also the last words of Yumi, Takako, and Tomohiko, though the latter had not actually heard that tape.
- The student he killed from his year, died differently in each adaption. In the manga, Katsumi beat his head in with a rock, in the anime, he pushed his classmate over and accidentally impaled him on a tree, and in the live action film, he became angry and strangled her to death due to the stress of the ongoing Calamity. However, in all versions, Katsumi is remorseful for his actions.
- It's shown that he and Reiko had a close relationship as they were in the same class and their conversation at the beach.