THE OP-FOR Taskforce is a group of Elite Spartans that were products of the Spartan II program and Special Ops Team: Ghosts originated from Earth(Aridna Quadrant).
Due to massive fluctuations of insurrectionists activity, the fire team was stationed for the defense of the planet Reach(Gamma Quadrant) in February 23, 2549. After winter contingency was declared on July 15, 2552, Fire Team OP-FOR led the battle of Sword base alongside with Noble Team (MIA) to secure radio dark location (32,-13,-102) from Covenant control. Fire Team OP-FOR lead the evacuation of New Alexandria in efforts to save civilians. When the Pillar of Autumn launched August 30, 2552 leaving hundreds of Spartans III's for dead, Fire Team OP-FOR survived colossal glassing and were extracted 294 hours after the halo events by Blue Team (status classified) on November 6, 2552.
After 2 week debrief, Spartans were re-commissioned at Cardio station (Earth space defense relay 24). Manning anti-air weapons, Spartans fended off the Covenant's initial attack. When Covenant battleships reached low orbit of earth, Fire team was granted pelican (class 284-b) to earth in defense of metropolis New Mombasa. The Flood infection Release on December 8, 2552, led the OP-FOR into pit holes outside of the city and regrouped with ODST's of Sargent Buck (34th division). They were extracted on a (Covenant class G) phantom back to Orbital Station Arian carrying important cargo (classified). A third of Fire Team OP-FOR was wiped out in this battle of earth (12 MIA).
When the second slip space rupture occurred, they followed with the Forward Until Dawn to the Forerunner super structure, The Ark. Providing tank and Air support, Fire Team OP-FOR moved with command of Sargent Johnson to claim control of the third required shield generator. Ambushed, Fire Team OP-FOR was temporarily declared MIA and Sargent Johnson was taken prisoner to the Light the Ark. Later found that 4 of Fire Team OP-FOR's Spartans were killed in combat and lost to flood infection on the Ark. The remaining 5 Spartans were taken back to Earth in critical conditions. The Anomaly states that 2 Fire Team OP-FOR Spartans (MIA) remained on the Ark Prior to its Destruction.
After the destruction of Installation 04, they were commissioned to attend Memorial of Fallen Soldiers in December 31, 2552. Now upgraded to the Status of Spartan IV program, the remaining 5 Spartans took in new recruits as they are reassigned to and independent contract Service. They felt their work in the Spartan II program suffered much loss from their original Fire Team with a 15 team body count. They currently hold the title as THE OP-FOR Clan.

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