Haruna Mutsuishi is a 16-year-old high school student born on March 21. She has light grey hair, grey eyes, stands 1.57 meters tall, and has blood type A. Her surname combines the kanji for "six" and "stone," while her given name means "light, sun, male" and "vegetables, greens."

Driven by a singular ambition, she aims to become a voice actress, a dream sparked by experiencing a particular work. She is a member of the unit Flower at the AiRBLUE voice acting agency.

She shares an important personal connection with a friend named Kamei, whose name translates to "turtle." In her professional pursuits, she attended an initial script reading at the agency where she performed a scene from Shakespeare’s *Hamlet* alongside fellow aspiring voice actress Maika Takatori. Their creative interpretation of the Hamlet and Ophelia scene reimagined the setting within a fantastical shoujo-inspired world.