Gashim is an elderly, kindhearted makemono demon-beast. After surviving the Azuma kingdom genocide, he journeys toward Osaka alongside companions including Buju and Himi. Previously captured by Caesar, he escaped death during the Kyō-Ō's Light of Judgment. Following his release, he travels with Amano Jaku, Buju, Ruddle, and other makemono to confront the Chōjin. During this trek, Gashim becomes separated from the main group with Buju and Himi, entering a mysterious city shrouded in fog and governed by children. Later, the group commandeers a Hell Worm—a creature sustained by the life essence and bodily fluids of abducted women—to reach Osaka by air. Throughout these perilous events, Gashim remains a core member of the ensemble navigating the ruined world.