The Federal Bureau of Internal Security (FBIS) is the covert intelligence and security agency of the Federal Confederation. Tasked with protecting internal stability, investigating political threats, and conducting surveillance operations, the FBIS operates in the shadows to safeguard the Confederation’s interests. While officially under the Federal Sheriff’s jurisdiction, the Bureau maintains high levels of operational autonomy, often reporting directly to the Federal Council.

Unlike the Federal Sheriff and Local Sheriffs, who enforce public law, the FBIS focuses on internal security threats, counterintelligence, and political stability, frequently working beyond the public eye.

The FBIS was formally established in 2634, during the second term of Federal Sheriff Evander Rosenberg, following increased concerns about rising political tensions, black market activity, and potential sabotage by Individualist factions in Firetown. The agency was designed as a preventive measure to monitor internal threats, particularly those that could undermine the Peace Treaty and the Federal Confederation’s governance.

After the assassination of Federal Sheriff Evander Rosenberg in 2635, the FBIS gained expanded authority under Mandla Friedberg's administration, taking a more aggressive stance on political dissent and counterintelligence operations.

The Federal Bureau of Internal Security (FBIS) operates under the nominal authority of the Federal Sheriff, but in practice, it maintains direct communication with the Federal Council and operates largely independently. The Federal Sheriff’s role is to enforce laws, while the FBIS ensures internal stability—a distinction that has led to tensions between the two institutions.

The FBIS can override the authority of Local Sheriffs if a case is classified as a matter of national security. However, due to concerns over overreach and potential abuses, all operations classified as “extreme interventions” must receive authorization from the Federal Council.