is a Japanese light novel series written by Chūgaku Akamatsu and illustrated by Kobuichi. As of June 2023, 39 main volumes have been published by Media Factory under their MF Bunko J label. A manga adaptation by Yoshino Koyoka started serialization in the seinen manga magazine Monthly Comic Alive in September 2009. An anime adaptation aired between April and June 2011. An original video animation (OVA) episode was released on December 21, 2011. A spin-off manga titled Aria the Scarlet Ammo AA by Shogako Tachibana was serialized in Square Enix's Young Gangan magazine from November 2010 to May 2018, with an anime adaptation by Doga Kobo airing between October and December 2015.
Plot
The setting of the story features , short for , a national qualification established to counter worsening crime conditions around the world. The Butei holders are trained in various specialized fields, and are permitted to possess various weapons and capture criminals. Kinji Tōyama is a student at Tokyo Butei High, a universal educational facility for the training of Butei. At this school, students with an aptitude for the work undertake special training in order to learn the path of the Butei. Shortly after Kinji decides to quit the Academy due to personal reasons, he is attacked by the Butei Killer, a criminal notorious for eliminating Butei—a case of the hunters becoming the hunted. The elite Butei Assault prodigy Aria H. Kanzaki comes to his rescue and from that moment on, Kinji's future as a Butei changes drastically.
The side story, Aria the Scarlet Ammo AA, follows Akari Mamiya, an E-ranked Butei who applies to become Aria's "Amica".
Characters
Main characters
A student at Butei High School. He was initially ranked E (lowest combat rank) due to missing the third term's final examination. However, when he is sexually aroused (such as sticking his face in a girl's chest, getting kissed or by him kissing a girl) he enters a state known as "Hysteria Mode" in which his cognitive and physical abilities increase to around thirty times his normal state, which allows him to perform feats of near-superhuman strength and skill, such as accurately shooting up the muzzle of an enemy gun, swinging his knife at supersonic speeds, and accurately shooting enemy bullets out of the air. Hysteria Mode is a genetic trait that all members of the Tōyama family possess, and is stated to be a highly evolved version of the natural male instinct to protect women. As such, when in Hysteria Mode, Kinji's major weakness is the fact that he cannot directly harm women, though he is still able to fight and restrain them without directly hurting them. In addition to this, Hysteria Mode also causes Kinji to develop a suave and seductive attitude towards women, which makes him very attractive to them while in Hysteria Mode. He is currently enrolled in the Inquesta department, though in the past, he was a prodigy (being rank S) of the Assault department, the most dangerous department in Butei High. Over the course of the series, Kinji grows to respect (and eventually develops romantic feelings for) Aria. He proves his feelings for Aria by kissing her on the lips in episode 5, though this is done to calm her down. Currently, his feelings for Aria are so strong that even the slightest bit of sexual/romantic involvement with Aria will instantly activate Hysteria Mode. His gun of choice is a Beretta 92F (which has been illegally modified to fire a three-round burst; he refers to it as the Beretta Kinji Model). He also wields a butterfly knife. In Volume 6 of the light novel he obtains a black Desert Eagle (which has been modified to fire in bursts as well as auto) which belonged to his father and a double-edged seax (modified with a hidden sheath and a reinforced rubber handle) which belonged to Sherlock Holmes. When he activates Hysteria Mode, he is able to dual-wield both the Beretta and Desert Eagle as well as the Butterfly Knife and the Seax, making him earn the title of "Quadra of Mimicry" in the series.