The Black Circle is the Interdimensional Federation's connection with the underground world of crime. They provide the information of secret societies and phantom people to the IDF as to maintain the security of the IDF. In addition the Black Circle functions as a crime syndicate and secret society of the IDF, being formed during the Babylonian Empire's formation.

The Black Circle has a total membership count of 78 Quadrillion people, 400 billion crime families, 50 trillion secret societies. They account for a minor amount of people to the IDF and have ties with every illegal business there is. Drugs, trafficking, assassinations, conspiracies, heists, robberies, raids, financial manipulation, tax evasion, corruption, terrorism, etc. You name the illegal activity the Black Circle has a firm grip on it.

The Black Circle is the main organization for the evacuations of "corrupted" people from the Unionverse. This includes Union Academy students, staff, and supporters. It also includes the rich, the perverts, the racists, the unspeakable acts committers, the enablers, the fake heroes, the fake in general, all the people that OCs and Y/Ns hate in Union Academy fics.

The Black Circle is also known for their revenge plots, both huge and petty in scale. They mainly take revenge plots against people who have been hit by karma in their lives, basically they throw adharma at people who have rightfully taken revenge and watch them lose everything before snuffing them out.

By this logic, the Black Circle is incredibly dangerous, even regular crime syndicates are disgusted by the Black Circle, making them the only organization that remaining corrupt people can be safe in once Union and their world order is destroyed.

The Black Circle is also one of the organizations that the leader of the IDF (Omnipotent) trusts with carrying out integration operations aside from Umbreon Industries and Union Academy. These operations take conquered territory and install the values of the DF into the people, forcefully too. 

Most information is classified, but what I can say is that the Black Circle would absolutely be richer than the Xeelee in terms of buying power and possession of assets. It also has more political power that the Xeelee in general.

Role: Crime Organization for the IDF