FORT HUNTER LIGGETT, Calif. -- If you're going to train the "good guys" in a military exercise, then someone has to play the "bad guys."

In most military training, the "bad guys" are the opposition force, or OPFOR. These Soldiers simulate the people and scenarios a unit may face when deployed to certain environments.

For Operation Warrior-Protector, a two-month training exercise held here for reserve units from across America, hundreds of individuals were needed to play OPFOR and create a series of simultaneous events to challenge the units being trained. Division West's 189th Infantry Brigade, "Task Force Cold Steel," supplied those individuals.

The Soldiers playing the role of OPFOR in training scenarios may be villagers who react to the military presence in their area. In one scenario, a military police unit must interact with village elders to search a village for a suspect. In situations such as this, one or two OPFOR individuals will act as the "bad guys," while the remaining OPFOR act as non-threatening villagers.

Sgt. Joshua Hammock, from Atlanta, Ga., is one of more than 140 OPFOR personnel brought in to support Operation Warrior-Protector.

"I expect to rattle (the training unit Soldiers') brains a little bit," said Hammock. "We want to make sure that these guys are ready for anything, but no hands on them, of course, and vice versa. We're going to make it as confusing as possible for them."

The OPFOR teams are a mixed bag of personnel, but Hammock says the Soldiers will adapt to each other to make sure the mission is a success.

"I do a little (standup comedy) in the civilian world," Hammock said. "I did some of that to help loosen them up and get comfortable role playing. This exercise is different because we are used to being (allied forces) and not OPFOR. But we will adapt and overcome."

In the village scenario with the military police unit, Hammock played the role of a drive-by shooter, and OPFOR role-players were instructed to not be hostile or seek interaction with the MPs until they decided to search the village.

As it turned out, the MP unit had a difficult time interacting with the OPFOR, although the MPs reacted to the villagers the best way they knew how.

The OPFOR Soldiers performed well, said Capt. Gregory Adkins, Trainer/Mentor Chief with 1-363rd Training Support Battalion, 189th Infantry Brigade.

"Those guys were confused out there. They didn't know what to do once you guys approached them for shooting into your village," Adkins told the OPFOR team. "They'll go back now and talk about what they need to do next time in order to not make the same mistakes."

Fort Hunter Liggett is the largest installation in the Army Reserve, with more than 160,000 acres of mountains, valleys, rivers, plains and forests. It provides ideal maneuver areas and state of the art training facilities.

The 91st Training Division, headquartered at Fort Hunter Liggett, trains and assesses Army Reserve units, and supports training for joint, combined and active Army forces. Thousands of Soldiers and dozens of units from around the country are participating in the April Combat Support Training Exercise, which provides realistic training for military maneuvers and tactics such as base security, convoy operations and battle reaction drills during simulated enemy attacks. The exercise provides realistic training to units to successfully meet the challenges of an extended and integrated battlefield.