Airi Isshiki is a first-year student in the main magic course at Third High School in Kanazawa. Hailing from the prestigious Isshiki family—one of the Eighteen Assistant Houses serving the Ten Master Clans—she exhibits pride and condescension toward those deemed lower-status or magically inferior, rooted in her sheltered upbringing as a lonely only child. Her family discouraged external friendships to prevent status exploitation. Her doting mother, originally from abroad, married into the Isshiki family and supported Airi during competitions. Airi possesses long blonde hair, purple eyes, and a striking appearance that fuels her popularity. Her personality merges a strong sense of responsibility with a superiority complex, particularly against non-numbered families. This manifests in suspicion toward Shiba Miyuki, whom she believes hides clan ties, and concern when Masaki Ichijo shows interest in Miyuki, fearing negative outcomes from associating outside elite circles. Despite initial aloofness, Airi values loyalty deeply, forming close bonds with Kanou Shiori and Tsukushiin Touko. She fiercely encourages them, revealing warmth once trust is earned. Her background includes fencing tournament achievements in middle school, highlighting physical prowess before magic specialization. Magically, Airi excels in movement acceleration spells, earning the epithet "Éclair" (Lightning) for superhuman reaction speeds. Her signature spell, Lightning, interfaces magic directly with her nervous system to enable instantaneous movement, bypassing cognitive processing. She wields a specialized pendant-shaped CAD with a cross that emits faint magical light during activation. During the Nine Schools Competition, Airi dominates the Rookie Crowd Ball event, defeating First High opponents Nanami Kasuga and Subaru Satomi through accelerated reactions. As a rare freshman participant in the main Mirage Bat tournament, she showcases elite skill. She also supports friend Shiori after Shiori's loss to Shizuku Kitayama in the Rookie Speed Shooting semi-finals, reaffirming their steadfast friendship.