Katsumi Matsunaga

He is a Yomiyama North Middle School student from the 3-3 class of 1983.

Appearance
He has brown hair and eyes.

Plot
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. 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. Afraid he would forget his findings, he recorded his theories and confession on a tape for the following years' students to find.

In Episode 8, after he learning 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. At the end of the episode,they witness Junta Nakao's death.

In the original novel, Matsunaga is never seen and only has contact with Tomoka Mochizuki.