The biggest Army exercise in Hawaii in over a decade just wrapped up, with about 5,000 soldiers playing both friend and foe as the fictional nation of Ari battled another government and Islamic extremists across a made-up Asia-Pacific archipelago.

Over nearly a week ending Friday, Schofield Barracks soldiers with the 3rd Brigade Combat Team tried to win hearts and minds in mock villages, evacuated personnel by helicopter, and fought a force of 600 enemy fighters equipped with SA-7 surface-to-air missiles, unmanned aerial vehicles and night-vision devices, officials said.

The 3rd Brigade came to the aid of Ari while other Schofield soldiers took on the roles of enemy fighters and civilians.

The Army said the new exercise, Lightning Forge, is a bit of back to the future — with some twists.

During the Afghanistan and Iraq war years, combat training occurred at smaller unit levels on Oahu.

“Brigade-level training exercises were executed on the island (before the wars),” said Col. Don Brown, the 25th Infantry Division operations chief, “but absolutely not like this level of instrumentation.”

As an example, a command post made up of reservists from the 100th Battalion, 442nd Infantry — which was assisting the 3rd Brigade — maneuvered virtual soldiers on Molokai, feeding the results back to brigade leaders overseeing actual soldiers in the field on Oahu, Brown said.

“As their electronic soldiers executed the orders they were being given by their real battalion staff, that generated feedback inside the simulation, and then that came up to the brigade commander,” Brown said of the 100th Battalion involvement.

Lightning Forge is expected to be a model for the future with so-called “nearpeer adversary focus,” meaning both sides have equal training and equipment.

Schofield’s 2nd Stryker and 3rd infantry brigades will rotate through the exercise every other year.

The soldiers will follow up at one of the big combat training centers on the mainland to reach the highest level of combat readiness the Army provides, officials said.

In May the 3rd Brigade’s 3,500 soldiers will travel to the Joint Readiness Training Center in Louisiana for the even more complex, largescale training.

The result — if the Army keeps both units on Oahu — would be one highly trained Hawaii brigade available each year for engagement or contingencies around the Asia-Pacific region.

Col. Scott Kelly, 3rd Brigade commander, said the future of actual warfare will probably look a lot like what his soldiers experienced during Lightning Forge.

“You have this very complex, hybrid-type threat composed of insurgent-type forces, largely ideologically driven. But then you also have essentially a nationstate level of capabilities, whether it be armor forces or (unmanned aerial systems) or just a professional military.”

The notional enemy in the exercise was “far more powerful than what we’ve been fighting over the last 10 years,” Kelly said.

In the scenario the Buddhist nation of Ari, made up of several islands, obtained the 3rd Brigade’s help in countering incursions made by Muslim Poema, which had its own islands but also a historic presence on Ari, officials said.

Another threat came from extremist black-clad Islamic Liberation Front fighters.

On wednesday in the Kahuku Training Area, a convoy of Army trucks snaked its way down a rutted asphalt road in a jungly area heading to a helicopter drop zone when a roadside bomb and trip wire were spotted.

Soldiers on foot took fire from enemy role players firing blanks and using a laser system and observers to confirm hits. Cracks of fire rang out, followed by three loud booms simulating mortar rounds.

Squad leaders shouted to their soldiers to get into better defensive positions as simulated wounded soldiers were helped or carried into Humvee ambulances.

“Get this more spread out!” yelled one soldier attempting to keep others from being a group target.

When the mock firefight was over, four 3rd Brigade soldiers were wounded, and one was dead. The enemy attackers were also dead.

“It’s hectic but I think it’s good practice,” said Spc. Tyler Meissner, 25, who has been in the Army 31⁄2 years but hasn’t been in combat.

“If we actually do deploy, we’ll be able to keep our composure,” said Meissner, who acknowledged his adrenaline level was “definitely high.”

“You are trying to do so many things at once, and you have people yelling at you and people shooting at you at the same time. I think it’s good training to have.”

As part of the exercise, Chinook helicopter crews picked up “refugees” from Dillingham Airfield and simulated dropping them off on the mothballed Navy ship Tarawa in Pearl Harbor.

Between 400 and 500 Schofield soldiers with the 1st Battalion, 21st Infantry, took on the roles of enemy fighters, civilians and Ari host-nation forces, the Army said. Air Force C-17 cargo aircraft conducted resupply air drops.

One 3rd Brigade battalion went into a town and tried to help the Ari populace, at one point getting thrown out when a fake video surfaced appearing to show U.S. soldiers abusing civilians. Officials said the complex scenarios were intended to challenge 3rd Brigade soldiers.

Kelly, the 3rd Brigade commander, said the ground in Kahuku “was very challenging to work through — which is exactly what we want.”

“If we are called upon to fight in the Pacific, the terrain alone is a leveling force,” he added.

Kelly said the 3rd Brigade soldiers were “fantastic.”

“There’s something special about the American soldier,” he said. “They fight very hard. They are smart. They are well trained and obviously well equipped, and they did superbly. Really, we sustained very few casualties given the level of that near-peer threat.”