S4

"We are stars. The Four Stars that light up the Aikatsu! World. Tirelessly serving as shining beacons in the sky. The radiance of S4 is... Eternal!"

- S4's motto

S4 is an idol unit comprised of the top four students at Four Star Academy, who are also at the top of the idol world. The unit is currently at its 27th generation, consisting of Yume Nijino, Ako Saotome, Haruka☆Ruka, and Mahiru Kasumi.

System
An S4 Selection is held at Four Star Academy every year, where selected students from each class compete with the current S4 member of each class. The new winner will be immediately appointed as the new S4 member. However, if one is going against a senior and have lost, they will be appointed only after the current member's graduation.

Members
Current Members= Former Members=
 * Yume Nijino
 * Ako Saotome
 * Haruka☆Ruka
 * Mahiru Kasumi
 * Hotaru Yukino
 * Anna Hibiki
 * Tamae
 * Momoko Yachigusa
 * Hime Shiratori (25th Generation)
 * Tsubasa Kisaragi (25th Generation)
 * Yozora Kasumi (25th Generation)
 * Yuzu Nikaidō (25th & 26th Generation)

S4 Main Coords

 * Light Blue Shine Stars Coord (Hime)
 * Red Shine Stars Coord (Tsubasa)
 * Violet Shine Stars Coord (Yozora)
 * Orange Shine Stars Coord (Yuzu)

Movie Special Live

 * Aurora Butterfly Coord (Hime)
 * Girls' Flag Coord (Tsubasa)
 * Asian Night Coord (Yozora)
 * Tropical Hula Girl Coord (Yuzu)

S4 Main Coords

 * Pink Shine Stars Coord (Yume)
 * Lime Shine Stars Coord (Ako)
 * Rose Shine Stars Coord (Mahiru)
 * Orange Shine Stars Coord (Yuzu)

Songs

 * episode Solo
 * Jewel Star Friendship☆ (25th Gen Photokatsu only)

Trivia

 * This is officially the first four-person unit in the entire Aikatsu! franchise.
 * This is the first permanent unit to include at least one idol from each type in the entire Aikatsu! franchise.
 * The is the first unit in the Aikatsu! Franchise to not have unit coords.
 * Unlike regular students, S4's members have custom uniforms of their own which differ them from the regular students and are worn year-round instead of switching between winter and summer uniforms.
 * This is the first unit where the members switch in and out due to a selection.
 * This is the second unit to do so in the entire Aikatsu! Franchise, the first being Aikatsu8, where it is a fan voting selection process instead of S4's top position competition.
 * The S4 Selection is similar to how the Starlight Queen Cup from the original series works, where they try to take down the student ranked the best in the school.
 * Similar to the Starlight Queen Palace, S4 has their own dorms separate from other students.
 * The 26th Generation is made up entirely of students who entered S4 in their first year.
 * Similarly, the 27th Generation is made up entirely of students entering their third year of middle school.
 * The Best Album of S4's 26th Generation, "Stars Shower" acted as a foreshadowing for the series' Best Album 2, titled "STARS☆SHOWER".