Kanako Azumi mirrors her daughter Ruka's reserved disposition. She was employed at Enokura Aquarium, ceasing attendance after Ruka's birth while retaining legal employment status. Her heritage stems from a lineage of traditional nude diving, a practice passed down from her grandmother and mother; this connection to the sea manifests later in a song sung by Ruka.

Her marriage to Masaaki Azumi suffers from mutual communication difficulties. Kanako tends to lash out emotionally and withdraw, sometimes involving alcohol, while Masaaki exhibits avoidance. Their conflicts create domestic tension, straining their relationship with Ruka. Despite initial emotional distance, Kanako demonstrates care for her daughter, particularly evident by the story's end.

Kanako's relationship with Ruka is complex, marked by emotional distance and misunderstandings rooted in Kanako's own troubled history with her mother. This generational pattern influences their interactions, with Kanako occasionally projecting unresolved issues onto Ruka. However, a shift follows Ruka's profound oceanic and cosmic experiences. The family reconciles as Kanako and Masaaki reunite, resulting in a new pregnancy that symbolizes their renewed bond and connection.