Mio Hirahara was a major antagonist in Blue Reflection Ray and amongst the supporting cast in Blue Reflection Tie. The older sister of Hirahara Hiori, Mio is the wiser, reserved, and controlled of the Hirahara sisters. Her wisdom and know-how is paired with her tendency to overthink things and worry often for the safety of others, often to her own detriment. Regardless, many resonate to Mio for her kindness and grace, and she is often the authority when there is none.