Aya Fujisaki is a human female from Earth and a student at Sainan High School, initially in class 2-D before advancing to 3-D. Born on March 20, she is a Pisces, stands 157 centimeters tall, weighs 47 kilograms, and has blood type AB. Her blue hair reaches her upper back with square bangs and chest-length strands framing her face. She has purple eyes, though they are almost always obscured by her large, round glasses. Her body measurements are 81-54-81 centimeters.

Weak-willed by nature, Aya displays a fangirl-like devotion to her friend Tenjōin Saki, whom she idolizes. This intense admiration began in childhood when Saki, alongside Kujō Rin, rescued her from bullies. Since that event, Aya has followed Saki with unwavering loyalty, typically appearing as a supportive presence within their group. She holds no romantic interest in Yūki Rito and often reacts with disapproval to his frequent accidental perverted incidents, especially when they involve herself, Rin, or Saki.

Aya’s role remains that of a loyal follower, consistently supporting Saki without significant independent story arcs or development. She is rarely depicted without Saki and Rin, functioning essentially as an extra within their circle.

In a unique display of skill exclusive to the 2008 anime adaptation, she demonstrates the ability to operate heavy machinery such as a crane, a cartoonish liberty not present in the manga.

Her relationships are defined by her connections to Saki and Rin. Her bond with Saki is built on gratitude, respect, and deep care, reciprocated by Saki who values their friendship enough to avoid opportunities that would separate them. Her friendship with Rin, though primarily mediated through Saki, dates back to their first meeting during the childhood bullying incident. No further media expands upon her background or development.