A first-year student at Third High along with Airi and Toko. Shiori was wallowing in shame after her family fell from grace, but Airi discovered her talents and brought her onto the team. Shiori has idolized Airi ever since. She is a master of using the magic sequence “Arithmetic Chain,” which allows her to make mathematical calculations quicker than supercomputers, as well as to instantaneously see the numerical formulas embedded in all things. She is not good at showing her emotions, but because she is always levelheaded, she is an essential adviser to her team.