Aria is a transfer student of Butei High School with a S Rank. She can wield two guns or two swords at the same time, earning her the title of a "Quadra". She saves 2nd-year student Kinji Tohyama from the infamous Butei Killer, who targets students who attends the school.
One of the highest ranked students that currently attends the special Butei High School after transferring there recently, Aria Holmes Kanzaki is a S-Rank in the famed Assault Department and has the skills to effectively wield two firearms or her two Kodachi swords at the same time, thus earning her the title of a "Quadra".
Aria Holmes Kanzaki was created by manga writer Akamatsu Chugaku in 2009 for use in the Hidan no Aria manga. It is not fully known as to what inspired them to create her at this moment.
Being a elite S-Rank member of the Assault Department at Butei High School, Aria is highly skilled when it comes to carrying out whatever missions or assignments that she is given to complete.