Aria the Scarlet Ammo Double A (TV Series)

Akari Mamiya is a freshman and E-rank student who looks up to her upperclassman, the S-ranked Aria H. Kanzaki. They both attend Tokyo Butei High School, which employs the "Amica" system, allowing an underclassman to train alongside an upperclassman. Akari is determined to be paired with Aria.