A 14-year-old in her third year of middle school. She wears a sailor-style school uniform. A beautiful girl with short black hair. She has a red birthmark on her right hand, extending from the wrist to the base of the thumb. She loves bananas. She has an older brother named Kun, who dislikes her. Though Mirai herself is unaware of the reason, Kun claims it stems from jealousy because his parents stopped doting on him once Mirai was born.

Mirai's older brother, 18 years old (estimated by adding his age at Mirai's birth to her future appearance's timeline). A high school boy. He speaks bluntly and dislikes his sister, Mirai. This is because his parents stopped pampering him like a baby from the moment she was born. He is quite cool and handsome; compared to when he was four, he has clearly grown into a much more refined and stylish young man.