Ayu Tateishi, an eighth-grade student, maintains a facade of cool composure that makes her popular at school. This stems from a childhood incident where her crush, Tetsushi Kaji, admired her apparent calmness during a pop quiz, though she was actually just fatigued. His comment led her to meticulously cultivate this "cool" image to impress him, suppressing her genuine nature. Her status is further solidified by her excellence as the captain of the girls' tennis club. Her life shifts dramatically upon meeting Nina Sakura, a transfer student revealed to be a witch from the Magical Kingdom. Initially skeptical of magic, Ayu struggles to accept Nina's secret but becomes her confidante and Secret-Keeper after witnessing magical mishaps. Nina's energetic and often chaotic influence becomes the catalyst for Ayu's development, causing her to gradually shed her constructed facade and reveal a more expressive, flustered, and genuinely emotional personality. Their friendship involves navigating magical antics, leading to arguments but ultimately strengthening their bond. Ayu's relationship with Tetsushi Kaji is central. Both maintain artificial personas to appeal to the other: Ayu as perpetually cool, Kaji as the universally kind "prince." This mutual deception creates tension. Ayu often attempts to use Nina's magic to win Kaji's affection, though these schemes typically backfire. Eventually, through Nina's intervention and their own realizations, Ayu and Kaji confess their true feelings and acknowledge their pretenses, beginning to date and transitioning to a more authentic relationship in both manga and anime continuities. Physically, Ayu has dark brown, waist-length hair, brown eyes, and a peach or pale complexion. She is most often seen in her school uniform: a pleated skirt, a blazer or sweater vest over a white collared shirt with a tie or bow, dark socks, and loafers. Casual attire, like a pink shirt with black sleeves, denim shorts, and sandals, is also documented. Beyond romance, Ayu demonstrates strong loyalty and protectiveness, especially towards Nina. She acts as the pragmatic "Straight Man" to Nina's whimsy but fiercely defends her when threatened, confronting antagonists like Sayaka Nakamura in the manga. She takes her duty as Secret-Keeper seriously. Her development culminates in a better balance between her innate conscientiousness and a newfound ability to express vulnerability and spontaneity, largely credited to her friendship with Nina.