Genzo Someya is a supporting character who serves as a childhood friend of the protagonist, Mayuko. He originally comes from the same rural area in Gifu as Mayuko and has recently moved to Tokyo, where the story takes place. As a young man, he is typically characterized as being stoic, often presenting a calm and unemotionally expressive exterior. Physically, he is a teenager of about seventeen years old with brown hair, black eyes, and a goatee. His appearance is frequently marked by a headband he wears.

His motivations are closely tied to his longstanding connection with Mayuko. Having known her from their shared past, he appears to care for her well-being in a quiet and understated way. The most notable expression of his personality and intentions is his recurring habit of carrying rice as a gift when he visits Mayuko and her alien housemate, NieA. This gesture is significant because it directly addresses Mayuko's frequent financial struggles and poverty, offering a practical and necessary form of support. In this way, Genzo acts as a dependable link to Mayuko's past and a stable presence in her otherwise unpredictable daily life. His role within the narrative is that of a supporting figure, reinforcing themes of community and quiet kindness without drawing excessive attention to himself.