Description
Aine Yūki studies at Star Harmony Academy, transferring from the general division to the idol division after meeting top idol Mio Minato while working at her family's Penguin Café. This encounter led to Aine partnering with Mio in idol activities under the unit name Pure Palette.

She possesses vibrant red-orange eyes with golden-yellow flecks and thick, curled pink hair featuring a peach ombre effect. Aine typically wears a sky-blue bow as a hair accessory, which changed from a headband in season one to a side bow in season two as her hair grew longer. Her fashion preference centers on the cute-type brand Sugar Melody, created specifically for her by designer Chiharu Hachiya after Aine expressed admiration for Chiharu's initial designs.

Aine's personality is characterized by relentless positivity and approachability, with a natural talent for forming connections. This aligns with her goal of making "one million friends," reflecting her belief that every interaction contributes to her dream. Her development reveals a deeper understanding of friendship's qualitative value, particularly through her bond with Mio; she explicitly states that even with a million friends, Mio remains irreplaceable.

She is the middle child of five siblings in a large family operating the Penguin Café, where she worked prior to becoming an idol. Her favorite food is the café's tomato basil and cheese sandwich. Her background includes minimal initial knowledge of the idol world, making her the second protagonist in the franchise unaware of Aikatsu before her debut.

Her journey includes debuting as part of a duet rather than a solo act, a first for a main protagonist in the franchise, and pioneering the use of a Rare coord instead of a Normal Coord for a debut performance. Across her idol career, she participated in units beyond Pure Palette, including temporary collaborations like Love Me Tear.

Trivia notes her birthday on July 20, coinciding with the initial proposal date for World Friendship Day and Japan's Marine Day. Her name carries significance: "Yūki" combines "friend" (友) and "hope" (希), while "Aine" can be written with kanji meaning "love" (愛) and "sound" (音). She is also the only protagonist whose idol aura never featured flowers.