Rau Minagawa, nicknamed "Miina" or "Mīna" by classmates, is the protagonist's middle school peer and the class's most popular student. Her vibrant energy and cheerful attitude define her presence.

She sports long brunette hair in twintails and a signature yellow blindfold or mask, typically worn over her eyes. Her uniform features a short skirt.

Rau bursts with high energy, expressing herself loudly and laughing infectiously. She sings with enthusiastic volume despite being tone-deaf, championing fun over technical skill in music.

Her background includes a close elementary school friendship with Kou Futou, her sole friend then. After Kou stopped attending school due to a traumatic cafeteria incident, Rau intentionally cultivates a lively, fun classroom atmosphere to soothe Kou's anxiety and encourage her return. This motivation fuels Rau's energetic behavior and focus on enjoyment.

Her name originates from the Japanese phrase "minna ga warau" (everybody laughs), reflecting her role in spreading positivity. In class, she occupies a window seat, sitting in front of Sunao Nako and beside Kako Kurai. During elementary school, Kou frequently woke Rau from her habitual classroom naps.

Through her popularity and dedicated efforts, Rau shapes the class environment into a welcoming, entertaining space for all students.