Kiyohara no Motosuke appears within the film's parallel narrative set during Japan's Heian period. He holds the position of provincial governor of Suō Province, residing in the regional capital Kokuga. This location geographically corresponds to the main 1955 narrative setting in Mitajiri, Hōfu City, Yamaguchi Prefecture.

He is the father of Princess Nagiko Kiyohara, a central figure in the historical storyline. His aristocratic status as governor confines his family, resulting in Nagiko's sheltered and isolated existence within their palace compound. This isolation fuels Nagiko's profound loneliness and longing for companionship, a key thematic element bridging the historical and contemporary narratives.

His portrayal shows him enforcing strict social boundaries appropriate to his status and era. This is demonstrated when he reprimands Nagiko for interacting with Chifuru, a girl of lower social standing, reinforcing the period's rigid class structures. His governance role and aristocratic standing define his presence. His status and actions directly influence Nagiko's isolation and emotional journey, which thematically parallels the contemporary protagonist Shinko's imaginative connection to the past.