The Special Forces was initially formed in the United States of America as the United States Special Forces with the goal of stopping international crime gangs, in particular the Red Dragon and Black Dragon clans. By the time of Mortal Kombat: Armageddon, the organization has become the Earthrealm Special Forces; while it was still an anti-crime organization, its mandate had expanded to defending all of Earthrealm against other dimensional invasions, such as by the Tekunin.
The Outer World Investigation Agency (OIA) was something of a successor to the original U.S. Special Forces, as many members of the U.S. Special Forces later join the OIA. The OIA later became the Earthrealm Special Forces. Sonya Blade convinced her Special Forces officers to create the OIA after being attacked by the Outworlders.