Miyako Aizen stands as a main character, renowned for her strict, diligent, and respectable nature. She enforces the same high standards upon herself that she demands from others, embodying her position as an honor student.

Her long dark purple hair and pale green eyes frame expressions typically serious and nonchalant, often featuring subtly furrowed brows; coy smiles are a rarity from her.

Deep concern for Kei Tōdō defines Miyako's personality, though this care frequently expresses itself through harsh or drastic actions. She exhibits possessiveness toward Kei, preventing extended conversations with Yuu and once discarding Kei's phone out a window to enforce bedtime. During this incident, Miyako panicked and blushed at Kei's desperate attempts to retrieve the phone, reacting to Kei's scent. She openly admires Kei's beauty, considering her the world's most charming and cute person. Concurrently, Miyako harbors a secret envy toward Yuu. Her interests include flower arrangement and an appreciation for beautiful things. She holds a strong aversion to rule-breaking, disturbances of discipline, or any disruption of order.

Miyako's background includes being classmates and roommates with Kei since middle school, during which she unofficially acted as dormitory prefect. Entering high school, Miyako grew unsettled by Kei's escalating smartphone addiction, primarily used to contact Yuu. Disturbances caused by Juri's performances solidified Miyako's view of Juri and her associates as troublemakers. To align with Kei's interests, Miyako joined the game Rebirth, forming the team TRenity alongside Kei and their classmate Yuki.

Key relationships feature Kei as her teammate and roommate, and Yuki as her fellow teammate in TRenity.