Kanou Shiori hails from a fallen magical lineage relegated to "Extra" status, a decline that fueled constant parental strife and imbued her with deep-seated inferiority and anxiety. Seeking escape, she was adopted into the prestigious Kanou family (designated as one of the Hundred Families, number Twelve), formally severing ties with her biological parents—though the psychological scars and fear of regression persist. As a first-year Course 1 student at Third High School in 2095, she serves on the school’s competition team. Her path shifted three years prior during a Libre Épée match, where Isshiki Airi recognized Shiori’s innate spatial awareness and calculation prowess. Airi secured her admission to the Kanazawa Magic Science Research Institute, where specialized training honed these talents into her signature magic: Arithmetic Chain. This magic manifests as special eyes that instantly convert observed phenomena into numerical formulas, enabling calculations exceeding human and supercomputer limits. It grants real-time tracking and prediction of seemingly random movements—like particle trajectories—while amplifying her spatial recognition and analytical abilities. In combat, Shiori deploys Arithmetic Chain for techniques like "Resonance Interference": generating intersecting oscillation waves that converge at a pre-calculated point to nullify data fortification magic, cast midair. Another application, "Friction Control," manipulates an object’s friction coefficient at high speed. During the Ice Pillar Break Competition, she zeroed friction on two pillars to slide them into a third, then maximized friction to create a reinforced structure against artillery magic. Shiori competed in the 2095 Women’s Newcomers Division Speed Shooter event, placing fourth after losing to Kitayama Shizuku. Despite her tactical brilliance, she struggles with emotional expression, maintaining a stoic exterior. Her analytical, level-headed nature makes her an indispensable team adviser. She shares close bonds with Isshiki Airi—whom she idolizes for transforming her life—and teammate Tsukushiin Touko. Physically, Shiori has purple hair and typically wears her Third High uniform. In attire-flexible competitions like Ice Pillar Break, she dons a white full-body fencing uniform as a symbolic gesture.