Ayu Tsukimiya is a 17-year-old girl with a youthful demeanor and petite frame, frequently mistaken for someone younger. Her distinctive style includes a red hairband, a winged backpack, and a tan duffel coat worn over a sweater and shorts, complemented by mittens and snow boots. Her personality blends impulsiveness and cheerfulness with a knack for clumsiness and a vulnerability to fear, particularly of supernatural elements. Seven years before reuniting with Yuichi Aizawa, their paths first crossed, though Yuichi’s fragmented memories obscure their initial meeting. Their connection reignites when she crashes into him while escaping a taiyaki vendor, highlighting her compulsive habit of swiping the fish-shaped snacks unpurchased—a quirk born from her enduring obsession. Central to her story is a relentless quest to recover a cherished item lost in her past, a pursuit marked by anguish when thwarted yet driven by unshakable resolve. She greets Yuichi with playful tackles that gradually soften into affectionate back taps as their bond strengthens. Though occasionally puzzled by mundane concepts like mobile phones, she approaches unfamiliar topics with eager curiosity. Her patchwork memories intertwine with Yuichi’s own amnesia, forging a shared journey to reconstruct their obscured histories. A childhood promise tied to her unresolved mission anchors her emotional arc, where moments of frustration or fear—often punctuated by her signature “ugū”—contrast with unwavering loyalty and warmth. In crossover contexts, her traits remain intact, featuring comedic taiyaki thefts and interactions brimming with impulsive yet heartfelt antics. No expanded backstory or development beyond her established narrative exists in spin-offs or alternate media.