Yuuta Togashi's friend from middle school with whom she went on delusional adventures. Shichimiya believes to have a magical ring called "Saturn VII" and calls herself "Sophia Ring SP Saturn VII."

During their middle school time, she realized that she fell in love with Yuuta but in the end decided not to change and remain a magical girl. Once reunited in present time, the old feelings eventually come back and she has to make the choice again - this time supporting Rikka.