Special Forces

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 Clan, Black Dragon Clan and DeVazzi Family. They were rivalled by GenSec. By the time of Mortal Kombat: Armageddon, the organisation has become the 'Earth's Special Forces'; while it was still an anti-crime organisation, its mandate had expanded to defending all of Earth countries against outerdimensional invasions, such as by the Tekuni Clan of China.

OIA
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 joined the OIA. The OIA later became the Earth Special Forces. Sonya Blade convinced her Special Forces officers to create the OIA after being attacked by the Outworlders.

Trivia

 * Special Forces is one of the 5 selectable factions in Mortal Kombat Xs online "factions" mode. The other 4 being: Black Dragon Clan, Lin Kuei Clan, White Lotus and the Brotherhood of Shadow.