Formers were Lambent Humans encountered during the Lambent Pandemic. Delta-One recorded the first sightings of these mutated humans in the seemingly uninhabited town of Mercy while looking for fuel to reach Azura. They later began to appear in many cities with large concentrations of Imulsion.
- "It's, it's, it's-it's some-some kinda fever. People started burnin' up, screamin' and fightin', turnin' crazy. And I'm damned if I'm gonna turn up like that, like some rabid dog, not even human no more!"
- — Crazy old man
Formers were the first example of Lambency in humans witnessed since the Sires almost a century earlier. Cities such as Mercy, Char and Halvo Bay began seeing the first signs of an epidemic with a fever. Soon, humans began turning into Lambent creatures, attacking everyone around them. While the infection was an advanced form of Rustlung, the Stranded believed it was something else since Imulsion was not known to be a parasitic life form at the time.
Mission to Mercy
Delta-One first met Formers in Mercy while looking for Imulsion to use as fuel to get to Azura, where Adam Jonathon Fenix was being held. The existence of Lambent humans was first implied when Delta-One met a crazy old man in the town of Mercy who had rigged the town's pipeline of Imulsion to explode. Extremely paranoid and unable to provide Delta-One with a clear answer as to why he had done this, he instead vaguely suggested that Mercy was suffering from some kind of epidemic before fleeing.
Delta-One would later come across the crazy old man's corpse in the sewers, with few clues as to how he died. In the same sewers, they would first encounter them. Marcus heard cries and found a Former crying, mistaking it for a female Stranded. The Former turned around and screamed at Marcus, and was quickly killed by him. Delta-One was later ambushed by more Formers in the sewers and believed that the Formers were just in Mercy and wanted to stop them from spreading all over Sera.
Delta-One later met with a Stranded survivor. After dealing with another Former horde outside Mercy's Town Hall, Delta-One, the Stranded survivor, and his near-infected friend were attacked inside by two Formers, who killed the Stranded. The group later fought more Formers while getting to the pump and more attacked while the squad was dealing with Locust from an airport they had passed through. All the attacking Formers, along with the Locust and other Lambent life forms that attacked, were killed when Dominic Santiago sacrificed himself to save his friends.
Mission to Char
When Delta-One activated the elevators in Griffin's Imulsion Tower, they believed that Formers were non-existent in the tower and were just in Mercy. After fighting through several groups of Lambent that were in the way, they eventually arrived at the tower. Delta-One activated the elevators. Marcus was suspicious of the sounds coming from the elevators and the squad was surprised when Formers burst out and ambushed them, from both the elevators and vents, but the squad was able to fend them off. Jace wondered if everyone would turn into Formers due to Imulsion exposure, but Marcus reassured him that they would not, as they had only been lightly exposed to it, while the Formers had greater exposure to it. As they arrived at the top and began searching for the Imulsion cargo, more Formers attacked them, but were all killed. 
Return to Halvo Bay
Formers were again encountered in the ruins of Halvo Bay when Damon Baird returned to the city with Augustus Cole and Clayton Carmine. They were also reunited with their old comrade Garron Paduk. As Paduk led them to a beached Imulsion rig, where his people were living at, Paduk was surprised to find no one around. The group investigated the area, only to be attacked by Paduk's people, who had turned into Formers. The group fought their way to the top of the rig, where Paduk launched a flare. When the flare was set off, Locust soldiers arrived and began attacking them. The Formers started joining the fight by jumping on the rig. After Damon and his squad were picked up by a Raven, the Formers fought against the Locust, although it is unknown who won the battle.
Formers will always attack in swarms. Unlike the majority of the Lambent Horde, which move at regular or very slow speeds, Formers move extremely fast. They can be compared to a Ticker, as both can cover ground very fast but are very frail, typically dying after a few hits from moderately powerful weapons like the Lancer, or one shot with more powerful weapons like a Gnasher Shotgun, provided that most of the bullets hit them. You do not need to worry with the explosion that comes after they die, as it is too weak to deal any significant damage to the player.
Despite their frailty, they still shouldn't be underestimated. In addition to their fast movement, they can attack very fast, easily downing a player in seconds on Insane difficulty. They will often swarm the player in circles, essentially "trapping" them. This can be avoided by putting yourself in a narrow area with one way of entry, allowing you to focus fire easily and prevent yourself from getting surrounded.
Fast-firing weapons like the Retro Lancer and Lancer are efficient at taking out hordes of Formers, as the few bullets needed and rapid fire are very helpful. The Retro Lancer's bayonet can take out Formers very easily in a straight line, as you will keep going until you stop or bump into an obstacle rather then impaling each one individually. Slower weapons like the Hammerburst II aren't recommended due to the slower fire rate which could get the player surrounded and have trouble killing them.
Behind the scenes
- Dizzy Wallin remarked that Mercy had been "busier than a fiddler's elbow" just a few months before Delta-One arrived, suggesting Lambency affected humans fairly quickly.
- The human population of Mercy marking their doors in red to save themselves from "the plague" references the tenth plague of Egypt, where all first-borns of those who did not mark their doorposts with lamb's blood were killed.
- Some Formers seem to have control of themselves, as if a player listens carefully in Campaign, one can hear a Former saying "Kill me!", however this tends to come from a female Former, not a male one.
- ↑ 1.0 1.1 1.2 1.3 Gears of War 3: Act III: Ghost Town
- ↑ Gears of War 3
- ↑ Gears of War: Judgment
- ↑ Gears of War: The Slab
- ↑ Gears of War 3: Act III: Brothers to the End
- ↑ Gears of War 3: Act IV
- ↑ Gears of War 3: Act V: Reckoning