Ayana Hizuki was forged through genetic experimentation by her biological mother at a laboratory specializing in human-animal gene splicing. Following numerous failed attempts, the breakthrough success merged her mother's own genetic material with that of an unspecified dog breed. Acknowledging the ethical implications, her mother orchestrated Ayana's placement under her aunt's care once she reached an age suitable for societal integration, instructing that she be given as normal a life as possible. Ayana consistently attributed her canine physical traits—animal ears and a tail—to a rare medical condition, an explanation generally accepted by others.

She enrolled in high school, founding and leading the Chemical Science Club. This role positioned her in direct rivalry with Airi Kuze, head of the Mechanical Science Club. Their competition focused intensely on securing the affiliation of fellow student Haruki Komaba, fueling ongoing tensions over both club membership and personal attention. Her maternal aunt, Touko Hizuki, later joined the school as a nurse, adding a familial connection to her daily environment.

Her personality displays traits reflecting her hybrid nature: energetic impulsiveness, occasional social misunderstandings, and a tendency toward naivety. These characteristics are occasionally intensified by physical sensitivities linked to her canine genetics. She demonstrates scientific aptitude through her leadership of the Chemical Science Club, though her academic pursuits intertwine with personal rivalries and social dynamics. Documentation notes frequent nudity as a recurring aspect of her depiction.