Nana Daigo is a supporting character in the story. She is a thirty-five-year-old woman who has been a close friend of Makio Kōdai since their student days. In contrast to Makio’s reclusive and socially awkward nature, Nana is vibrant, assertive, and socially adept. She is cheerful and warm-hearted, and she demonstrates a strong sense of responsibility toward those she cares about. After the death of Makio’s sister, Minori Kōdai, Nana becomes a frequent presence in the Kōdai household, often stepping in to handle domestic matters and provide practical support. When she learns that Makio has taken in her orphaned niece, Asa Takumi, Nana promptly visits to check on them and ensure they are managing. Her role in the narrative is that of a reliable friend and an anchor of normalcy, offering both emotional and logistical assistance as Makio adjusts to life with a teenager. Nana’s motivations are rooted in her long-standing friendship with Makio and her desire to see her friend and the new household thrive. Her key relationship is with Makio, but she also interacts with Asa, serving as a warm and approachable adult figure. Throughout the story, she remains a steady presence, helping to bridge the gap between Makio’s isolated tendencies and the social world. Nana does not possess any supernatural abilities; her notable strengths lie in her social confidence, practical competence in everyday tasks, and her unwavering loyalty to those she considers family.