- "In Honor of Those Who Served To all those we lost during the Pendulum Wars, may they rest in peace, and know always that their brave sacrifices were not in vain. Never shall they be forgotten."
- — Landown Memorial
The Pendulum Wars was a massive, global, 79 year-long conflict waged by the two superpowers of Sera, the Coalition of Ordered Governments and the Union of Independent Republics, for control of the planet's natural resources, namely Imulsion. Millions of human lives were lost in the conflict and the environment was significantly damaged by devastating weapons. The war was a deadlock for the majority of the years, until the COG broke the stalemate by going around the land warfare with the UIR and staging a daring raid in Aspho Fields. The COG stole the Hammer of Dawn technology plans during the Battle of Aspho Fields, and gained the advantage in the war. The Pendulum Wars ended shortly before the attack on the surface of Sera by the Locust Horde on Emergence Day, with only six weeks of peace between the two wars. 
Decades before the Pendulum wars, Sera was plunged in the millennia long conflict known as the Age of Armageddon, nearly destroying both the human race and Sera. The humans rejected war and embraced a new era of peace, the Era of Silence, leading to a period of advancement of arts, science, and culture. But the shortage of energy led the fragile planet to more problems. Imulsion, a phosphorescent and low-viscosity fluid that was discovered by an oil-exploration drill, was unusable as an energy source until Dr. Helen Cooper created the Lightmass Process, which enabled production of cheap energy from this previously useless substance, marking the beginning of the Gold Rush. What no one knew at the time was that Imulsion was actually a parasitic organism that would one day bring the planet to the brink of extinction.
The full implementation of this process guaranteed a new energy source and led to the elimination of the need for hydrocarbon and nuclear-based fuel. However, the extremely low price of Imulsion energy and the massive loss of revenue and jobs in the traditional energy-producing industries soon caused Sera's world economy to collapse. The few countries that discovered an abundance of Imulsion below their land shortly thereafter found themselves at war with the many nations who were not as fortunate and the Era of Silence ended as the Pendulum Wars began.
The Rise of the COGEdit
During the seventy-nine year war, the Coalition of Ordered Governments, or COG, became a legitimate, if minor, political party. Founded long before the Pendulum Wars by fanatical socialist Alexiy Desipich, the party was based on an obscure world-government philosophy based on eight guiding principle values: Order, Diligence, Purity, Labor, Honor, Loyalty, Faith, and Humility. The COG began sending out their legions of Gear soldiers turning the Pendulum Wars from a conflict over Imulsion to a fight over freedoms. The Coalition overthrew many nations' vassal governments and accepted volunteers to fight the UIR armies.
79 Years of WarEdit
- "Like everything in the COG army, there's an acronym for street fighting: M.O.U.T. "Military Operations in Urban Terrain." We just know it means close, personal, and higher casualties. In the Pendulum Wars, some guys couldn't take it. Black outs, freaks outs, suicides. You didn't give 'em shit because its might be you someday. To win M.O.U.T. battles, you need numbers, the manuals advise three to one odds to beat an entrenched urban force. If we're lucky the odds might be three to one day--against."
- — Dom on urban warfare
One of the most notorious fronts of the war, the Eastern Front saw the Duke of Tollen's Regiment of Tyrus battling Gorasni soldiers loyal to the UIR. Several Gears were captured and sent to the Ramascu labor camp and several perished in the camp. The events of the Eastern Front and Ramascu left a great distrust for the Gorasni people among the COG citizens and Pendulum War veterans.
- "Your priority is to stop the UIR advance within Kashkur. COG forces hold the central plains of the country and the extreme west, but the UIR is widening its corridors between the areas we still hold. The Anvegad Pass is blocked and must remain so if we are to stop the UIR closing the circle and inserting land forces from the east."
- — Col.James Choi, commander of 6th Brigade.
The COG defended the Imulsion rich nation of Kashkur [western border] from the UIR nation of Furlin. The COG was able to contain and hold off the Indies until the president of Vasgar resigned shortly before a vote of no confidence. This gave the UIR the opportunity to invade Vasgar and open a second front on Kashkur, allowing the UIR to attack the infamous fortress of Anvil Gate on the southern front. While an Indie army flanked on the western border from Furlin, their aim was the city of Shavad.
The COG response to the Indies sending “peacekeepers” to Vasgar was to stop all Imulsion supply to neutral Vasgar, in turn hurting the Imulsion Company and putting millions of Vasgar citizens in the dark, effectively shutting down the power stations and hospitals. The operation would force the UIR to ship in supplies from neighboring friendly UIR nations while having to deal with a local population without a government and fuel. The only thing of military value left for the UIR in the Imulsion-starved nation would be the iron ore and vast factories in southern Vasgar. That is, if the UIR could keep the peace in the nation.
Indie troops from Furlin invaded Kashkur from two fronts: on western border hitting the city of Shavad, and Anvil Gate on the Vasgari border in the south. On the Vasgari-Kashkur border, Indie's sabotaging effectively cut off Anvil Gate's only land route by destroying the canyon, showing that the UIR had dozens of Special Forces in the country before the fall of the Vasgari government. An Indie soldier with a RPG in the nearby cannons was able to kill Captain Sander and several other Gears, leading Lieutenant Hoffman to request a Pesang detachment. However, High Command was unable to deliver fresh supplies or reinforcements since every Tern and the newly introduced King Ravens were occupied with combat missions in Shavad.
The UIR laid siege to Anvil Gate, where the COG, with a handful of Pesang commandos defended the Gate from overwhelming forces, the siege lasted three months and the fort was reduced to rubble from Mortar attacks, Hoffman's Pesanga troopers were able to kill several Indie spotters in the hills, but with the lack of food and after executing a civilian, Hoffman was forced to face the facts on the ground. He realized that Anvil Gate and the garrison could not last any longer, but fortunately for Hoffman, the Indie Major allowed the civilian population to evacuate the garrison if the COG surrendered. Hoffman took the only option he had left and ordered the surrender of Anvil Gate to the Indies, but Hoffman's surrender was a ruse. He planned to entrap the Indies in the old quarter of the city. The plan worked, and over 200 Indie soldiers were killed, though the Gears suffered many casualties, too. The victory at Anvil Gate allowed the COG to hold the southern pass and launched then Major Hoffman's career.
Indie invasion of Irohma islandEdit
- "We're not saints. But we are gonna win this fucking war and I'd rather have you on the winning side."
- — Marcus Fenix to Tai KalisoFour years before E-Day, the UIR attacked Irohma Island, defeating the local population. Elements of the 26th Royal Tyran infantry landed on the island and ended up recruiting a local.
- "They say that an Indie guard post and a COG one faced each other across a border for ten years and didn’t so much as exchange a shot...I forget where it was. I bet they did, too."
- — Gunner EvanFor ten years, Gears and Indie soldiers located on two guard posts never exchanged fire for ten years. Gunner Evan while stationed at Anvil Gate would later recount the anomaly.
- Main article: Raid on Gralia
Since 17 B.E. the UIR and COG fought for control over the nation of Sarfuth. While neutral Maranday stopped any outright invasion by the two superpowers, the UIR was amassing forces in the Republic of Lauczi to attack Sarfuth. COG forces decided to take an Indie strategy and used Maranday's neutrality to launch a daring raid into Indie territory. The raid was successful and COG forces were able to use their air force and take out the advancing Indie army at the Maigar Pass.
Around 3 years before E-Day, Indie saboteurs were operating from neutral Maranday to attack Sarfuth's Imulsion pipelines, while members of the 26th Royal Tyran infantry defended the areas and killed at least one saboteur.
- Main article: Operation: Leveler
The climax of the war was at Aspho Fields with Operation Leveler. COG forces discovered that the Indies at Aspho Point had won the arms race for orbital weapons. The COG could not allow the UIR to have an advantage in the war, so they prepared for a daring raid, mobilizing the 26th Royal Tyran Infantry and Navy in an amphibious assault on the Ostri coast. The 26 RTI attacked the Ostri troops at Aspho Fields while the commando detachment under Maj. Hoffman raided Aspho Point. The Indie forces inflicted heavy losses on the COG, but the COG managed to accomplish their mission and evacuated from Ostri. The operation had the largest number of Embry Star recipients in Coalition history.
After the raid at Aspho Point and the Battle of Aspho Fields, the COG would battle the UIR for another two years, losing thirty-thousand soldiers. Adam Fenix used the stolen Hammer of Dawn technology to create satellite-based weapons for the COG. For his efforts, Chairman Tomas Dalyell awarded him the Octus Medal. COG forces were able to advance into both Furlin and Ostri. On the coastal city of Bonbourg, the COG occupied the city, but the UIR Third Fleet bombarded the city until the COG unleashed their newest weapon, the Hammer of Dawn. The Hammer destroyed five Indie ships and forced the fleet to withdraw. While in Furlin, Indie troops battled in Ghato City and around several cliffs. After the Hammer strikes on the Indie fleet, Premier Yori Deschenko entered into negotiations with the COG and the UIR surrendered. Despite this, some UIR units continued to fight, believing the surrender was COG propaganda, while the Gorasni would continue a guerrilla war.
The COG's armed forces revolved around its Army branch until the Battle of Aspho Fields. Their Special Forces and Navy were given less attention, though Adam Fenix argued that the Navy and Air Corps must be expanded. The COG Navy contained battleships in the early years of the Pendulum Wars, and had a diverse range of ships including destroyers, submarines, and helicopter carriers.Two years before E-Day the COG Navy attacked and leveled Berephus and Bonbourg, while LCTs landed on Aspho Fields. The UIR Navy, along with the Gorasni Navy, had submarines and missile frigates that were able to survive the Pendulum Wars and Locust War. During the Pendulum Wars, the UIR had Tennad sailors use suicide submarines against the COG.
- "The people of Sera will once again be united...sharing in the invaluable gift of Imulsion as once-optimistic discoverers always envisioned. Both rich and poor nations alike, turning point, may I be the first to salute the world as we enter this golden age of prosperity, and peace."
- — Chairman Tomas Dalyell remarking on the results of the Pendulum Wars, with Sera becoming unified and entering a new golden age. 
- "At 1000 hours this morning, the Union of Independent Republics signed a formal surrender to the Coalition of Ordered Governments and concluded a peace treaty. It is with profound relief that I tell you the Pendulum Wars are now at an end, and that the COG and UIR will embark on a program of reconciliation and rebuilding to heal the terrible scars-individual and national-that this long, terrible conflict has left upon Sera. We hope that the state of Gorasnaya will come to accept our offer of reconciliation and formally agree to the cease-fire in with other UIR states."
- — Chairman Tomas Dalyell's official announcement that the Pendulum Wars are over.
 After the final battle of the war, the COG and UIR signed an armistice ending the war in the COG's favor. The COG replaced several Indie nation governments with pro-coalition governments, including Pelles and Ostri Republic, which were under the administration of Premier Yori Deschenko. Some Indie nations refused to surrender and launched an insurgency, mainly the infamous Republic of Gorasnaya. The Day of the Fallen holiday was created to celebrate the fallen Gears soldiers.
- "Should I tell Dalyell what's coming? No. I can still stop it happening. I can avoid more bloodshed. I'm the only one who can."
- — Adam Fenix
 For six weeks, the COG ruled almost all of Sera, before Emergence Day. Just as they started to rebuild the cities and towns that were destroyed and fix international relations with the UIR nations who were still fighting against the COG, an unidentified enemy that would come to be known as the Locust Horde, emerged from the underground warrens of Sera and launched a planet-wide invasion of the surface; the COG was unable to hold back the Horde, losing all they gained in the 79-year Pendulum Wars. However, the COG war machine was able to mobilize from the Pendulum Wars allowing them to quickly regroup and counter the Locust during E-Day, resulting in a new long war of extermination.
15 years after E-Day, the survivors of the Republic of Gorasnaya joined the COG for protection from the Locust before the Lambent Pandemic forced the COG to disband and caused the Gorasni to leave the coalition. However, the Gorasni remained allies with the remnants of the COG, saying that while they remember their grudges, they also remember kindness and those that are their allies, coming to the aid of the COG remnants during the Second Battle of Azura where Adam Fenix destroyed the Locust and the Lambent with an Imulsion-targeting weapon, bringing peace to Sera once again.
A lesser observed effect of the Pendulum Wars was significant damage inflicted upon Sera's environment. While Imulsion was cleaner than traditional energy sources, its large-scale exploitation by the massive war machines of Sera polluted the Planet's soil, oceans, and air. This caused rampant cases of rust-lung in Humans during and after the Wars and would eventually contribute to the Lambent Epidemic as many had been at least marginally exposed to Imulsion. The battles of the Pendulum Wars had scared many regions of Sera. Both the COG and UIR committed serious human rights abuses in depriving civilians of natural resources. All of these factors began to change Sera's larger climate as HMT Magazine reported a noticible increase in catastrophic hurricane storms in the later years of the Pendulum Wars. While tragic, this environmental degradation would pale in comparison to the subsequent Locust War which nearly rendered Sera lifeless.
- "This is how my grandfather fought wars."
- — Major. Adam Fenix on the state of the Kashkur Front
- "And now we go and do it all over again. Another pointless battle. Another bereaved family. Another year of war. And the UIR does exactly the same. Someone has to break the cycle. Someone has to create weapons so powerful that if politicians want to wage war, they'll face the same death as the men and women send to fight it. A deterrent. A damn big deterrent. I can build a deterrent that'll bring governments to their sense. An orbital weapons system. That's my duty now."
- — Adam Fenix envisioning the Hammer of Dawn.
- "Some have said that war is hell. War is not hell... for in hell, innocence is spared."
- — Tai, after discovering the ethnic cleansing of his village
- "And now you can see what we are fighting for. Imulsion."
"I thought we were fighting for democracy."
"No, I'm pretty sure it's Imulsion, Quinn. Cars don't run on freedom. Whatever that is."
- — Helena speaking with Pvt.Quinn about the COG's motivation for fighting the Pendulum Wars
Behind the ScenesEdit
The Pendulum Wars may be named after the Pendulum, which is a weight suspended from a pivot so it can swing freely. It is most likely a representation of the war and its stalemate until the Battle of Aspho Fields. It can also be suggested that it is a reference to the number of machine-related names in the Gears of War universe.
|47 B.E.||Ostri Front|
|17 B.E.||Kashkur Front (Fall of Mendurat · Siege of Anvil Gate · Battle of Shavad · Battle of Ragani) ·UIR occupation of Vasgar · Raid on Gralia|
|4 B.E.||Raids on the Acastu Imulsion Fields · Battle of Irohma Island|
|3 B.E.||Sarfuth-Maranday Border Incident · Battle of Aspho Fields|
|0 B.E.||Skirmish in Ghato City · Battle of Bonbourg · Skirmish on Furlin cliffside · Armistice between the UIR and COG|
|Unknown timeline||Battle of Branascu · Bombardment of Mercy · Conquest of the South Islands · Eastern Front · Bombing of Sikorla · Battle of Autrin · Battle of Berephus · Third Battle of the Plateau|