The Lambent Pandemic is an event that occurs in the Gears of War series. Going back as far as before the Pendulum Wars between the UIR and COG nations, the pandemic stemmed from the spread of a parasitic organism known as Imulsion which originated from deep within the Hollows of Sera. When humanity first discovered Imulsion, they found no evidence to suggest that the substance was in any way alive, but it was volatile and produced large amounts of energy, and so humanity began utilizing the substance as a source of fuel to replace dwindling supplies of oil. However, the true nature of Imulsion would be realised decades later during the apocalyptic Locust War, only by then, Imulsion had begun infecting and mutating many life-forms that remained on the surface of Sera, threatening to wipe out all life on the planet.
The Lambent Pandemic occurred (to Humans) around the early years of the Pendulum Wars. The COG discovered that Imulsion had mutagenic and teratogenic effects on Humans after long exposure but early effects are known as a bad cold called Rust Lung. After building the New Hope Research Facility, the COG and Department of Health wished to find a cure and keep the effects in secret. However, the effects led to the creation of poisoned, mutant Humans known as Sires and information leaked out of office. This caused the children of the Sires, known as the Locust to be relocated to Mount Kadar in the Inner Hollows, the Sires put in stasis, New Hope shut down, and all records of the facility erased.
Though the New Hope Research Facility was shut down, Imulsion research did not stop, but was merely relocated. In the early years of the Pendulum Wars , the COG built a resort bunker on the remote island of Azura. The bunker was designed as an evacuation point for COG leadership, scientists, and high-profile citizens in the event of a global catastrophe. Late in the Pendulum Wars, the COG began forcibly moving scientists to Azura, whilst telling the public that the kidnapped scientists had died.
17 years before Emergence Day, Morpholigist Dr.Elain Fenix, while exploring a Hollow cave, found a dead Rock Shrew that inexplicably had an extra, vestigial, pair of legs. Believing she had discovered the last remaining member of a genus long thought extinct, Elain inferred that mutated shrew was in fact a genetic relative of a six legged creature from a children's bedtime story. Though her husband, Dr.Adam Fenix, thought the legs were merely be a random mutation, Elain was ardent in her belief that the shrew was related to the long extinct creature, and had the research data to back up her claim. What Elain could not have possibly known at the time was that the creature she had discovered was in fact suffering from Imulsion infection and the mutations were a sign of Lambency.
Though this was humanity's first (publicly known) encounter with Lambency, the creatures in the Hollow, including the Locust Horde, were subject to the effects of extreme Imulsion exposure for much longer. At least 9 years before Emergence Day, Lambent creatures had organized themselves to such an extent that they were able to fight the Locust on at least even terms, marking the beginning of the Locust Civil War. When Elain returned to Hollow eight years later to follow up on her discovery, the Locust leader, Queen Myrrah, had her executed to prevent a premature human discovery of the Locust. Four years later Adam, following his late wife's journals, traced her body to the Hollow where he too crossed paths with the Locust. While there he discovered the true extent of the Lambent threat and found out about Queen Myrrah's plans to leave the Hollow and colonize the surface at the expense of Humanity. Trying to prevent a war between humans and the Locust, Adam met with Myrrah some five years before Emergence Day, and assured Myrrah that he had the expertise and resources necessary to find a cure for Lambency. All she needed to do was give him the time to find it. Myrrah gave Adam five years to find a cure, but after repeated failures the queen's patience finally ran out. The Locust enacted their plan to leave the Hollow, resulting in the start of the Locust War.
Throughout the course of the Locust War, Chairmens Tomas Dalyell and Richard Prescott continued the pre Emergence Day policy of moving key scientists and research personnel to Azura. When the COG learned Adam had known about the Locust and the Lambent years before E-Day, Prescott evacuated him and his assistant to Azura in an attempt to discover a way to destroy Lambency. Adam brought with him a sample of Imulsion and the remains of the Rock Shrew Elain had found years earlier. Desperate to find a cure, Adam injected himself with Imulsion, and discovered its true nature; that Imulsion was, in fact, a parasitic fungus-like life form. Adam also determined that, in as little as a few years, Imulsion would destroy or infect all other forms of life on the planet. After numerous attempts to cure the infection via traditional methods failed, Dr. Fenix developed the Imulsion Countermeasure Weapon which killed Lambent cells using a wave of targeted radiation that would envelop the entire planet. Unfortunately Adam did not have the time to fine tune the weapon, meaning that it would also kill any creature that had been heavily exposed to Imulsion even if it was not fully Lambent yet. This included the entirety of the remaining Locust Horde.
As early as the first month after Emergence Day, COG Soldiers and Officials spotted Wretches that appear to glow a golden colour and are volatile even after death. Once was said rumor in the COG during the Battle of Halvo Bay became real. The COG was then forced to inform Gears of the glowing Wretches and their dangers.
14 years after E-Day, the COG began the Lightmass Offensive by building the Resonator to map out the Locust tunnels and destroy them with the Lightmass Bomb. When Delta Squad was ordered to infiltrate the Lethia Imulsion Facility to plant the Resonator, Sgt. Marcus Fenix and Pvt. Dominic Santiago, Augustus Cole, and Damon Baird called in command the glowing Wretches in the courtyard of the facility. Command warned them that Lambent Wretches have been reported and they explode on command or when killed. Delta Squad had to clear the Lambent Wretches in the facility and the Outer Hollows to plant the Resonator.
Since the Resonator failed, Delta Squad downloaded the mapping data from Haldane Hall which was used to put in to the Lightmass Bomb on the train delivering it to the Hollows. Along the way, Lambent Wretches boarded the train and attempted to cut the train's power and disconnect the rest of the train.
Delta was successful in defeating both the Lambent Wretches and General RAAM and bombing the Outer Hollows. However, the Lightmass Bomb proved more of a disadvantage to the Humans and the Locust. Because Lambency spreads through Imulsion fumes, a majority of the Imulsion in the Outer Hollows evaporated into the atmosphere. It spread into the Inner Hollows and created more numbers for the Lambent army trying to overthrow Nexus. For the Humans, the Lightmass Bomb brought back what became the beginning of the Pandemic, Rust Lung.
Unfortunately for the survivors and soldiers stationed near Timgad and other Imulsion Townships, the Lightmass Bomb caused the return of Rust Lung. Cases were reported in civilians of Timgad and soldiers stationed there, including Jonathan Harper and Michael Barrick. The Rust Lung spread as time went on, eventually infecting every Human on Sera around 17 A.E.
Eventually, Rust Lungs patients were geared up along with healthy soldiers to fight in Operation Hollow Storm.
Operation Hollow Storm
Due to the Lightmass Bomb awakening the Riftworm and realizing the danger of Jacinto sinking, the COG ordered nearly all able bodied men to dig into the Hollow and destroy the Locust. In the midst of the first wave, Prescott realized the only true way to locate Nexus and Queen Myrrah would be to trace their steps back from the New Hope Research Facility where they first studied Lambency and created the Locust Horde. Prescott "declassified" the disk and ordered Delta to investigate the facility for any leads on the Locust stronghold and their Queen.
Upon entering the facility and going through "clearance," Delta comes across the abandoned facility and the security system based off the personality of Dr. Niles Samson. While Delta traversed the facility, they finally found the intel leading them to Nexus through Mount Kadar via recorded message, the last message about the children. However, doing this awoke the Sires, the Lambent Humans, and attacked Delta. Delta escaped, killing most if not all of the Sires and managed to reach Nexus, the Locust capital.
When Delta planted the beacon and began the second wave of Hollow Storm in Nexus, the COG discovers a horrible truth. Upon invading the main tower, Delta discovers the Locust are fighting with their Lambent brethren. At the same time that the COG is invading Nexus from above, the Lambent are attacking from below, coincidentally weakening the stronghold's defenses and making it easier for the COG. They eventually discover how the Lambent are what caused the Locust to emerge and attack on E-Day. Queen Myrrah wishes to invade and conquer the surface while she leaves the Lambent in the Hollows. But she began following an old plan made by Adam Fenix to evacuate the Locust Horde to the surface and sink Jacinto City which would drown the Lambent in the flooded Hollows. She was unsuccessful as the Humans sank Jacinto first which caused a majority of the Locust to die while the water rose the Imulsion into the soil and the ocean, accelerating the Lambent Pandemic.
The Lambent were responsible for apparently anonymous attacks on fishing vessels around Pelruan. Among the vessels the Lambent sunk was a UIR frigate. Evidence of Lambent stalks was found aboard one vessel - a stalk had punched straight through the hull and released Polyps. Marcus Fenix, accompanied by Bernadette Mataki, encountered what seemed to be a Drudge aboard a fishing vessel; it mutated multiple tentacles and exploded when killed.
Attack on Emerald Spar
Delta discovered the Lambent Stalks heading towards the Emerald Spar Imulsion Platform and quickly headed there to defend it. Two stalks ended up punching up through the well bay of the platform and released hundreds to thousands of polyps. In the battle that followed, one of the stalks was destroyed, but the platform caught on fire and was eventually abandoned. The platform ended up collapsing into the ocean while the Lambent seemed to retreat as there was no sign of the remaining stalk afterwards. This deprived the COG of their only source of Imulsion.
Assault on Vectes
First Battle of New Jacinto
Preparing for an invasion of Vectes by Lambent Stalks, the COG was surprised when three Lambent Leviathans attacked the island with two heading to New Jacinto and one smaller one heading to Pelruan. The Leviathans unleashed hundreds of polyps that the defending forces were forced to battle. The polyps were lured into traps and killed while the COG Navy tried to take out the Leviathans. Eventually the subs CNV Clement and Zephyr managed to get a lock on one of the Leviathans and blow it with a combined torpedo attack while the other one was lured into a trap by Delta-One using the CNV Falconer and was killed by Damon Baird with the Hammer of Dawn which also destroyed a third of a New Jacinto. This Leviathan beached and released a couple hundred more polyps, but these were dealt with.
Battle of Pelruan
While the First Battle of New Jacinto was going on, a third, smaller Lambent Leviathan was attacking Pelruan. The Leviathan released polyps in three waves that attacked the town and destroyed KR Three-Three. Eventually the Leviathan was killed by the crew of KR-239 which unleashed all of its ammo into the Leviathan's head, killing it. The Leviathan exploded, nearly destroying the King Raven and the rest of the polyps were killed.
Further attacks and collapse of the COG
For several months following the battles at New Jacinto and Pelruan, the Lambent continued to besiege the island from stalks and in one case, another Lambent Leviathan. Various Lambent creatures including polyps, Lambent dogs, Lambent cats, and a Lambent bull were released all over the island. This also resulted in the creation of an Imulsion field on the island, allowing the COG and their Gorasni allies to refuel for the first time since Emerald Spar was destroyed. Eventually, after New Jacinto came under attack by Lambent lifeforms and Pelruan was flooded, the COG was forced to disband and abandon Vectes to the Lambent and head to the mainland which was also besieged by Lambent forms.
18 months after the sinking of Jacinto, Chairman Prescott abandoned the COG and vanished, leaving the last remnant of the COG to fend for themselves - as Stranded. Marcus Fenix and Delta squad took up residence in CNV Sovereign along with many other Gears and civilians. While the Sovereign was sailing through Lambent waters, a large group of Lambent Stalks emerged from the ocean around the ship, forcing Delta to defend it. Around this time, Richard Prescott landed in a King Raven with two Gears, bringing a message to Marcus from Adam Fenix revealing he's still alive and being held captive by the Locust. The Lambent also sent a Lambent Leviathan to attack the ship and though it was killed by a crate of Tickers being dropped on it, the ship was destroyed in the process along with Centennial Bridge. During the Mission to Hanover, Delta also came into conflict with Lambent lifeforms.
The Lambent later attacked Anvil Gate, sending three Stalks with Lambent Drones, Drudges and a Lambent Berserker. Most were killed by the retreating forces while the rest, except the Berserker were killed by the Hammer of Dawn. The Berserker survived a direct strike, but was killed by multiple shots to its Imulsion core.
During the Mission to Mercy and the Mission to Char, the Lambent attacked with most of the enemies in Mercy being Lambent Humans who had been turned Lambent due to Imulsion exposure. In order to destroy the Lambent and Locust forces in Mercy, Dominic Santiago was forced to sacrifice himself to ram a fuel tank with a vehicle, causing a massive explosion that obliterated all but the Gears who escaped. At Char, the Lambent took over an Imulsion refinery and attempted to prevent Delta Squad from getting fuel from it, but failed.
During the Second Battle of Azura, the Lambent attacked, attempting to prevent Adam Fenix from detonating the Imulsion Countermeasure Weapon that would destroy them, sending a variety of forms to attack. The attack failed as the weapon activated and destroyed all Lambent in the area as it powered up. The weapon went off completely and destroyed all Lambent lifeforms across the planet and all Imulsion, ending the invasion and the pandemic.