Emi Handa is the mother of the protagonist, Seishuu Handa, and the wife of Seimei Handa. She is a stay-at-home mother who manages the household affairs and dedicates herself to the well-being of her family, having ceased her own public artistic work after the birth of her son. Physically, Emi is a youthful and attractive woman with pale skin, shoulder-length black hair, and grey eyes. Her typical attire is a pink kimono with a green obi, often covered by a white apron.

On the surface, Emi presents a gentle and motherly demeanor, but this appearance belies a much more impulsive and emotional personality. She is fiercely devoted to her son, yet her love manifests as intense overprotectiveness and a tendency to be overbearing. She is prone to crying easily when upset, a trait she shares with one of the island's young children, Hina Kubota. When words are not enough to express her frustration, Emi resorts to physical violence, often punching those who have angered her. While these outbursts are frequent, her punches are noted to be not very strong, and her husband, Seimei, has become skilled at dodging them, though he sometimes allows her to vent her anger on him when he understands the cause of her stress.

Emi's primary motivation throughout the story is her concern for her son Seishuu. She was vehemently against his father’s decision to send Seishuu to the Goto Islands as a form of exile and retreat after he punched a respected calligraphy curator. She believes she has always acted in Seishuu's best interest, having sheltered him to the point where he grew up socially awkward and naive. When Seishuu returns to Tokyo, she is the most vocal about him staying and interprets the changes in his personality from his time on the island—such as his use of local dialect and his more expressive nature—as strange and troubling. Ultimately, her motivation is to protect her son from any perceived harm or negative influence, even if that protection inadvertently hinders his personal growth.

In the narrative's final arc, Emi plays a crucial role as an obstacle that Seishuu must overcome to demonstrate his newfound maturity. She actively attempts to prevent him from returning to the island, clinging to the image of the quiet, docile son she believes she raised. However, her character develops as she witnesses a significant change in Seishuu. Upon seeing his nostalgic and genuine emotional response to simple gifts from the island children and observing how much he has come to care for others, she finally relents and allows him to go back, recognizing that his time away has been beneficial for him. This act signifies her growth from a purely protective figure to one who can accept her son's need for independence.

Emi's key relationships define her role in the story. Her bond with her husband, Seimei Handa, is one of deep love despite their contrasting personalities. While Emi is emotional and impulsive, Seimei is calm, patient, and understanding. She addresses him affectionately as daa-chan, a nickname that surprises those who know his strict public persona, and she dislikes being separated from him. Their arguments over Seishuu's future are central to the family dynamic, but their mutual respect and affection are always evident.

Her relationship with her son is the most significant. She is overprotective and prone to misunderstanding his life on the island, once jumping to a comical and incorrect conclusion that he had developed an interest in BDSM. Despite this, her love for him is genuine, and her eventual acceptance of his choices is a testament to her character development. Her interactions with other characters highlight her volatile nature. She has a notably poor relationship with Takao Kawafuji, her son's friend and manager, whom she often punches, leading him to develop a genuine fear of her. Similarly, she holds a strong animosity towards the art curator Kirie Kawafuji, despising him for looking down on her son's work. Their shared admiration for Seimei is their only point of common ground.