Miyu Kouzuki is the main protagonist of the story, a junior high school student with long straight blonde hair and bright green eyes. She is a good-natured girl who possesses a kind, generous, and motherly personality, often cheerful and ready with a smile, though she also has a soft heart that is easily touched. Her background is defined by her parents, who both work for NASA and leave for the United States at the start of the series, arranging for her to stay with a longtime family friend named Hosho Saionji, a monk who lives at and runs a Buddhist temple on a hill overlooking the town of Heiomachi. However, Hosho himself departs soon after on a year-long pilgrimage to India, leaving Miyu to live in the same house with his son, Kanata. This sudden abandonment by her parents, who frequently prioritize their work and use her to fulfill their own wishes, is a recurring source of weariness for her, yet she remains fundamentally cheerful and friendly. Her central motivation stems from her deep affection and sense of responsibility for the people placed in her care, most notably the alien baby Ruu, who arrives unexpectedly and whom she comes to love as a mother figure. In the story, Miyu serves as the emotional anchor of the household, balancing the chaos introduced by Ruu's psychic abilities and the daily challenges of school and friendship. Her key relationships include a complex dynamic with Kanata; initially disliking the idea of sharing a home with a boy, she often fought with him, but she gradually learns they were friends as toddlers and develops genuine romantic feelings for him, culminating in marriage years later. She also shares a profound bond with Ruu, who sees her as his mother due to her caring nature, and she responds in kind, understanding the loneliness he feels. Her development traces a path from a girl reluctantly thrust into an unusual living situation to a mature young woman who embraces her role as a caretaker and builds her own family, eventually marrying Kanata and living together at the temple. In terms of notable abilities, Miyu does not possess supernatural powers; her strengths lie in her emotional resilience, her nurturing instincts, and her ability to remain kind and composed even when faced with the ridiculous situations brought on by Ruu's powers and the various alien visitors.