Kikurin is the protagonist of the film and the eleven-year-old daughter of the titular character, Nikuko. She is a preteen girl navigating the tumultuous transition into adolescence while living with her mother on a small boat moored in a quiet, sleepy coastal port town. In terms of appearance and temperament, Kikurin is presented as the polar opposite of her mother. Where Nikuko is described as rotund, loud, and boisterous, Kikurin is thin, reserved, and often appears as the more mature and responsible member of the household. Her personality is characterized by a deep sense of embarrassment regarding her mother’s unashamed and exuberant behavior, which she perceives as a social liability.

Kikurin’s primary motivation stems from a desire for stability and normalcy, which has been elusive due to her mother's romantic history. The pair have moved constantly because Nikuko repeatedly falls for untrustworthy men who exploit her kindness, forcing them to restart their lives elsewhere. Now that she is older, Kikurin is weary of this nomadic existence and longs to settle down, fit in with her peers, and avoid the humiliation she feels is caused by her mother’s antics. This manifests in her daily life at school, where she is cautious about her social standing. She finds herself caught in the middle of typical pre-adolescent conflicts, including a complicated friendship with a wealthier girl named Maria and disputes over basketball games during lunch. Simultaneously, she begins to explore a quiet crush on a classmate named Ninomiya, a strange boy who makes odd faces and with whom she feels a sense of affinity.

Throughout the story, Kikurin’s primary role is that of the observer and narrator of her own coming-of-age journey. Her perspective shapes the entire narrative, which is told through snippets of her daily life, internal anxieties, and vivid imagination. The central dynamic of the film is her relationship with her mother, Nikuko. Despite her frustration and embarrassment, Kikurin does deeply care for her mother, though she struggles to reconcile Nikuko’s cheerful optimism and naive outlook with the harsh realities of their situation. Other key relationships include her friend Maria, where a rift occurs after Kikurin refuses to choose sides in a petty school dispute, and the mysterious Ninomiya, who helps her begin to understand that it is acceptable to be different and that her own harsh judgments might sometimes be cruel.

In terms of development, Kikurin undergoes a significant emotional evolution as she confronts her own fears of being an outsider. She initially views her mother’s happiness and resilience as a flaw, but through her experiences and interactions, she begins to see that Nikuko’s ability to face heartbreak and hardship without regret is a form of strength. The narrative follows her as she learns to stop resenting her circumstances and instead embrace her own identity, culminating in a realization that she does not need to conform to a strict idea of normalcy. As for notable abilities, Kikurin possesses no supernatural or extraordinary physical skills. Her most prominent characteristic is her rich and active imagination, which frequently manifests as internal monologues or surreal visual interludes where animals or inanimate objects voice her darker, more cynical thoughts. This imaginative perspective allows the audience to access her inner world as she processes her feelings about her mother and her place in the world.