Aria Shibuya is a supporting character in Love Live! Superstar!! and is best known as the younger sister of the main protagonist, Kanon Shibuya. She is depicted as a second-year middle school student when she first appears, later advancing to her first year of high school as the series progresses. In terms of appearance, Aria has a slim figure with short brown hair that features a blonde ombre, and she is typically seen wearing glasses. Her blue eyes are another notable aspect of her design, though some sources describe them as purple, depending on the artistic interpretation.

Regarding her personality, Aria is portrayed as a thoughtful and observant individual who shares a close bond with her family. Like her father, she has a deep love for reading and is often seen with a book during her free time. Initially, she was somewhat skeptical about her older sister's decision to become a school idol, but she quickly grows to become a steadfast supporter of Kanon and her group, Liella!. She is generally calm and level-headed, often reacting with mild confusion or curiosity to her sister's more eccentric moments, such as when Kanon sings unusual songs around the house. Despite not sharing her sister's passion for performing on stage, Aria is consistently encouraging from the sidelines.

Aria's role in the story is primarily that of a family anchor and a source of quiet support for Kanon. She appears regularly in scenes set at the Shibuya family home and café, providing a sense of normalcy and warmth. Her most significant contribution to the plot occurs when she inadvertently helps Kanon overcome a childhood trauma related to singing. By describing her older sister's childhood personality as someone who was passionate, loud, and a bit relentless but in an endearing way, Aria provides Kanon with the perspective needed to find her own voice again. She is also present at several key Liella! performances, cheering from the audience alongside her mother. During the school's open campus event, Aria visits Yuigaoka Girls' High School, showing particular interest in the library and the school's history, but she ultimately decides not to attend the same high school as her sister, a choice that distinguishes her from many other siblings in the franchise.

Aria's key relationships revolve around her immediate family. She shares a loving and supportive dynamic with her older sister, Kanon, as well as with her parents, who run the family café. While she interacts with members of Liella! when they visit her home, her primary role remains within the family unit. Her development throughout the series is subtle but clear: she transitions from a slightly questioning younger sister to a fully committed supporter who actively cheers for Kanon and her friends. By the third season, she has entered high school and continues to maintain her close relationship with her family, celebrating their successes and offering comfort during difficult moments, such as when Kanon is苦恼 about studying abroad. Notable abilities of Aria include her keen observational skills, as seen when she provides insight into Kanon's past, and her affinity for reading, which is depicted as a defining personal trait. Her name itself carries musical significance, as Aria is a term for a expressive melody in opera, paralleling her sister Kanon, whose name is a homophone for canon, a musical form.