The grandfather of Rin Shima (リン の祖父; Rin no sofu) appears occasionally throughout the series. Although his name is unknown, her personality is very similar to that of his granddaughter, Rin Shima; taciturn, contemplative and a traveler who has a motorcycle that constantly travels between different mountainous areas of Japan. This wandering and globetrotting life has caused him not to spend much time with his family. His daughter receives his calls from time to time and she would like him to spend more seasons with them at home so he can see his granddaughter grow up.
Apparently, he is primarily responsible for encouraging Rin toward more traveling and a globetrotting life (although she hasn't quite gotten to the globetrotting part).
- He is the Narrator for both the Yuru CampΔ and the Heya CampΔ semi-sequel.
- He has had interaction with at least one member of the Outdoor Activities Club, Chiaki Ōgaki; he gave her some roast beef while she watched him from afar on one of his solitary forays into the mountains.