Miuna Shiodome is a central character in the anime A Lull in the Sea, first introduced as a quiet and emotionally mature third-grade elementary school student. She is the daughter of Itaru Shiodome and his late wife Miori Shiodome, who was originally a resident of the sea village Shioshishio. This mixed heritage, half-sea and half-land, is a defining aspect of her identity. After losing her mother at a young age, Miuna developed a deep-seated fear of losing those she loves, which influences her relationships and actions throughout the story. She initially struggles to accept Akari Sakishima, her father’s new partner and her mother’s friend, but eventually comes to embrace her as a stepmother, calling her Mom.

Personality-wise, Miuna is reserved and often depends on her best friend Sayu Hisanuma to voice her thoughts. She has a subtle way of expressing her feelings, such as leaving notes stuck with gum on walls. Despite her quiet demeanor, she is highly intelligent, thoughtful, and courageous. After a five-year time skip, she matures into a more self-assured middle school student, though she retains some insecurity. Her kindness is evident as she shows compassion even when dealing with complex emotions like jealousy.

Miuna’s primary motivation is her unrequited love for Hikari Sakishima, who becomes her step-uncle after Akari marries Itaru. She harbors deep feelings for him from a young age, but suppresses them because she knows Hikari is devoted to Manaka Mukaido. In spite of her own heartache, she supports Hikari in his efforts to help Manaka regain her lost emotions. This selflessness culminates in Miuna taking on the role of the Maiden Sacrifice during the second Ofunehiki ceremony, replacing Manaka and falling into a slumber while acknowledging her love for Hikari.

Her role in the story is pivotal, as she bridges the gap between the surface and sea worlds. Through her emotional journey, she awakens her Ena, the special ability of sea people to breathe underwater. This ability reflects her growing connection to her mother’s heritage and her own identity. Miuna’s development traces a path from a shy, loss-affected child to a strong and empathetic young woman who learns to embrace her family and her mixed origins while navigating the pain of unreturned love.

Key relationships include her best friend Sayu, who provides unwavering support; her stepmother Akari, with whom she eventually forms a loving bond; and Hikari, who cares for her deeply as a younger sister. Her feelings for Hikari remain one-sided, but she finds the courage to act for the sake of others. Miuna’s ability to communicate through small gestures and her quiet resilience define her as a character who holds the weight of emotional complexity, much like the tides her name metaphorically attempts to still.