Aria the Scarlet Ammo Double A (緋弾のアリア AA Hidan no Aria Dabur Ei?) is a spin-off series from the original Hidan no Aria series by Shogako Tachibana. The series started serialization in the seinen manga magazine, Young Gangan on November 5, 2010 and finished on May 18, 2018. There have been 14 volumes published by Square Enix. A light novel adaption of the series was written by Hidan no Aria writer Chūgaku Akamatsu with illustrations by Kobuichi and published on January 25, 2015. An anime adaptation was announced, and began airing on October 6, 2015.
Akari Mamiya is an Rank E freshman who looks up to her senior, the S-ranked Aria H. Kanzaki. They both attend Tokyo Butei High School, a school that trains its students as Armed Detectives otherwise known as "Butei" to society. Individual student training aside, the school employs the co-operative "Amica" system, allowing an underclassman to train alongside an upperclassman. Akari is determined to be paired with Aria.
- Young Gangan Manga Official Website (Japanese)
- Hidan no Aria AA Anime Website (Japanese)
- Aria the Scarlet Ammo AA in Anime News Network encyclopaedia