HIDAN no ARIA

Kinji Tohyama (遠山 キンジ Tohyama Kinji)Protagonist of the series and a student at Butei High school. He was ranked Level E (lowest combat rank) due to missing the Butei evaluation exam. However, under certain "conditions" his level raises to the highest combat status of Level S. He is currently enrolled in Inquesta department. After the death of his brother, he now plans on quitting Buteiand live a normal life by transferring into a normal high school. His weapons of choice are Beretta M92F (which was illegally modified to fire a three-bullet burst. He refers to his own gun as Beretta Kinji Model), and a butterfly knife.

Aria H. Kanzaki (神崎・H・アリア Kanzaki H Aria) is a female transfer student of Butei High school. An "Assault" department elite rank S (The highest rank) Butei, she wishes to recruit Kinji after their encounter. She can wield two guns or two swords at the same time, earning the title of a "Quadra". Her weapons of choice are M1911 pistol (also known as colt government) for guns, and two undersizedJapanese swords known as "Kodachi".

Shirayuki Hotogi (星伽 白雪 Hotogi Shirayuki^?) is a female student of Butei High school, Childhood friend of Kinji. Enrolled in Butei's special department known as SSR. Buteirank A. She's the current student council chairman. She is also a president of various clubs like the gardening club, handicraft club, and girls volleyball club. A perfect Japanese beauty according to Kinji, except for one flaw. For some reason, she turns into a berserker and usually assaults the girls that involves Kinji (Obviously because she loves him and she does not want any girl to approach him). She uses a Japanese sword named Irokane Ayame as a weapon of choice. 

Riko Mine (峰 理子 Mine Riko^?) is a female student of Butei High school, friend of Kinji. She's also enrolled in ButeiInquesta department like Kinji, she calls him Kii-kun. Although known as the biggest idiot in Kinji's class, she seem to hold a lot of information including info on students of Butei High school. She is seen with a heavy inclination of customizing her uniform into Lolita style. Weapons of choice are double Walther P99 for handguns and double daggers for melee. Like Aria, she also had earned the title of a "Quadra". 

Reki (レキ^?) is the Snipe department's ace. Butei rank S. Real name unknown. She's habitually taciturn, constantly impassive and indifferent in fashion. She's always seen with a large headphone over her head. Her signature quote is "I am a single bullet. It has no heart. Therefore, it does not think. It just flies straight towards its target", which she always say before she shoots her target. She can shoot anything without missing her target within 2km radius. Her personal weapon is a Dragunov sniper rifle. 

Jeanne d'Arc 30th (aka Durandal / Diamond Dust Witch) is an ability user of ice properties from the organization EU. During the events in Volume2 of the light novel, she is targeting Shirayuki in attemp to kidnap her and force her to join EU. She is captured with the combined efforts of Aria,Kinji and Shirayuki during the season of Adseard. As one of the conditions of Plea Bargain forces her to stay in Butei High as a 2nd year international student from Paris enrolled in Informa department. Both Riko and Jeanne get along with each other to the point that she taught Riko strategy-making techniques, while Riko taught her how to mimic people's voices. 

Kinji considers him as a Tranportation Otaku. This is all due to his knowledge about all kinds of vehicles may it be on land, sea or air. Also, for the ease of maintaining it, this guy chose to use a Colt Python revolver. But the gun’s loading capacity is small, and it cannot equip a suppressor, so normally no Butei would use it. Also, no girls like Muto. Even though he isn’t a bad guy, he's too wild.