Ayaka Shindo operates a photo studio in Nagatsuki City, outwardly human yet secretly a powerful nine-tailed fox youmu. Her true form grants significant abilities, including crafting potent barriers for protection and containment. She stands as both guardian and mentor to her younger sister, Ai Shindo, a cat youmu who helps at the studio while attending high school.

Ayaka maintains vital connections within the spirit world, acting as an intermediary for Akihito Kanbara by receiving and handling postcards from his often-absent mother, Yayoi. Typically calm and composed, her humor sometimes surfaces as teasing, like publicly sharing Yayoi's embarrassing messages despite Akihito's protests.

During critical events such as "The Calm," which weakens youmu, Ayaka intervenes to shield Ai when Akihito's own youmu side nearly attacks her, demonstrating fierce commitment even while personally diminished. Her photo studio serves as a nexus for spirit-world activities, including youmu stone appraisal and trade. Ayaka's extensive knowledge of spirit world affairs makes her a key informational resource for figures like the Nase siblings, though her deeper motivations and full history remain partially veiled.

Throughout the series and films, she consistently upholds her role as a stabilizing presence, balancing business operations with her responsibilities towards Ai and her intricate connections to other supernatural entities within the city.