Ayaka Shindou is a nine-tailed fox youmu who integrates into human society. She operates as an appraiser of youmu stones and runs a photography studio that also functions as a cafe catering to ordinary humans. Her human guise presents as a woman with straight dark gray hair reaching her chest and green eyes, standing 165 cm tall. She typically wears a black kimono adorned with red floral patterns, a yellow haori featuring beige dots, white socks, and zōri sandals with red straps.

Ayaka maintains a generally calm and level-headed demeanor, often acting as a knowledgeable intermediary between humans and the spirit world. Despite her composed exterior, she displays a sharp, occasionally cruel sense of humor, exemplified by publicly sharing embarrassing messages from Yayoi describing her son Akihito Kanbara. She serves as the intermediary for Yayoi's special postcards sent to Akihito. Ayaka has collaborated with Spirit World Warriors in Nagatsuki City for at least three years, despite her youmu nature.

She resides with her younger sister, Ai Shindou, a cat youmu who attends high school and helps at the photography studio. Ayaka exhibits strong protective instincts towards Ai, reassuring her during threats and maintaining a gentle, supportive relationship. During "The Calm," an event weakening youmu, Ayaka defended Ai against attacks, fending off adversaries like Miroku Fujima. She was later absorbed by the colossal youmu "Beyond the Boundary" but survived and assisted in defeating internal threats.

Ayaka possesses significant abilities, including expertise in evaluating youmu stones and constructing potent barriers. One barrier repels ordinary humans, allowing only Spirit World Warriors into her studio; another dome-shaped barrier can obliterate multiple youmu simultaneously. In her nine-tailed fox form, she projects powerful energy blasts and erects protective shields, retaining considerable strength even during The Calm.

Across various media, Ayaka appears in the anime series as a secondary character connecting Akihito to spirit world matters and appraising Mirai Kuriyama's youmu stones. In the sequel film *Kyoukai no Kanata: I'll Be Here - Mirai-hen*, she engages in serious discussions with Hiroomi Nase about the Nase family's future, with Ai later explaining Ayaka's "high expectations" of him. She also makes a cameo in the ONA *Kyoukai no Kanata: Idol Trial* as a studio customer during Ai's idol-themed activities.