Katsumi Matsunaga

Katsumi Matsunaga attended Yomiyama North Middle School's Class 3-3 in 1983, alongside Reiko Mikami and a classmate named Ryoko Akiyama, and is the only known person to have successfully stopped that year's calamity partway through, rather than simply enduring it until the end.

By the time Kouichi Sakakibara and his classmates track him down, years later, working at a beachside hotel, Katsumi has buried much of what happened, growing visibly agitated whenever the class curse comes up in conversation.

A tragedy on the beach while the group waits for him ultimately jolts loose the memory he needs, and Katsumi is able to point them toward a recording that holds the key to how his own class ended its calamity, information that proves decisive, if not entirely without cost, for Class 3-3 in 1998.