Aria Holmes Kanzaki (神崎・H・アリア Kanzaki H Aria) a.k.a. Sherlock Holmes the 4th, is a demon, female transfer student of Butei High school. An "Assault" department elite rank S (The highest rank) Butei, she wishes to recruit Kinji as a partner 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 undersized Japanese swords known as "Kodachi". her main goal is to defeat the IU and exonerate her mother . She also starts to have feelings for Kinji but shows it in a different way than other people.
Aria has a background as a Butei in Europe, namely England, and this is attributed to her lineage as a descendant of Shelock Holmes. Aria seems to have started becoming a Butei there, and so this is most likely where she has earnced her title of Quadra and her S-Rank.

Aria Holmes Kanzaki (神崎・H・アリア Kanzaki H Aria) a.k.a. Sherlock Holmes the 4th, is a demon, female transfer student of Butei High school. An "Assault" department elite rank S (The highest rank) Butei, she wishes to recruit Kinji as a partner 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 undersized Japanese swords known as "Kodachi". her main goal is to defeat the IU and exonerate her mother . She also starts to have feelings for Kinji but shows it in a different way than other people.
Aria has a background as a Butei in Europe, namely England, and this is attributed to her lineage as a descendant of Shelock Holmes. Aria seems to have started becoming a Butei there, and so this is most likely where she has earnced her title of Quadra and her S-Rank. It has been mentioned that she has received the title of "Dame".