Gears of War Wiki
Gears of War Wiki

This article, Lightmass Bomb, may require cleanup. Deploy Delta Team to East Barricade Academy and retrieve the data immediately!

The Lightmass Bomb is an imulsion bomb created supposedly from a process similar or related to Dr. Helen Cooper's Lightmass Process.


While it is always referred to as a bomb, it functions as a cluster of highly explosive guided missiles/torpedoes in practice. Due to the nature of the Hollow and its Imulsion-flooded tunnels, this torpedo-based design was the most efficient way to deploy the Lightmass warheads. Consequently, the weapon requires an immense amount of data on the area between the launch point and targets to guide the individual projectiles. It is a very destructive weapon when used effectively.

Lightmass Offensive[]

Main article: Lightmass Offensive

The data was originally to be provided by the Resonator sonic mapping device, but when the device did not perform as planned, data collected by Adam Fenix had to be substituted. After being deployed at Timgad Valley from the derailed Tyro Pillar, the projectiles successfully filtered through the underground tunnels and destroyed a significant population of the Locust, as well as the Kryll breeding grounds. Unfortunately, while the Outer Hollows were destroyed, the Inner Hollows survived the explosion and the majority of the Locust survived to rebuild. Within six months, the Locust returned stronger than ever. A side-effect of the Lightmass Bomb was that one of the Riftworms was awakened, giving the Locust a major weapon in their war against humanity.

Sinking of Jacinto[]

Main article: Sinking of Jacinto City
"We're screwed. We lost the Lightmass Bomb."
Damon Baird to Marcus Fenix, before the latter comes up with a new plan

As part of the plan to sink Jacinto in order to destroy the Locust Horde by flooding the Hollows with seawater, a second Lightmass Bomb was prepared as it was believed to be powerful enough to do the job. Cole and Baird remained behind to help prepare the bomb while Marcus Fenix and Dominic Santiago entered the Hollows through a giant Locust sinkhole in order to open a hole to drop the bomb. They succeed, but their Brumak went Lambent and knocked the helicopter carrying the Lightmass Bomb into the Imulsion. Another plan had to be formed after the loss of the Lightmass Bomb and ironically, the Lambent Brumak was used as the bomb itself by detonating it with the Hammer of Dawn, completing the mission and apparently killing off the Locust Horde. While it's later revealed that the Locust survived, most of the Horde died in the flooding and those that survived split into two factions.

Detonation Process[]

The Lightmass Bomb's HUD.

It is unknown what process allows the bomb to become so powerful, but it is surmised that refined (or possibly even raw) Imulsion has explosive properties. This would also explain why the Lightmass Process can harness energy from Imulsion; if it were explosive, the energy released from said explosions would be usable, in a similar way to petroleum and diesel fuel, harnessing energy for the masses. It is very possible that torque bow arrows use a miniature Lightmass process, releasing the Imulsion's energy in an explosion.

Another hypothesis, which is somewhat substantiated, is that it uses a process related to the Lightmass Process to "detonate" Imulsion, giving it increased destructive power depending on how much Imulsion is present when detonated. This would mean that the Lightmass Bomb would be less of a bomb itself and more of a catalyst to the reaction created when it makes contact with Imulsion. This is quite possible, since Imulsion-exposed Dark Wretches gain a similar, explosive quality.

Behind the scenes[]

An unfinished render of the Lightmass Bomb.

  • It has been revealed that the detonation of the Lightmass Bomb at the end of Gears of War sent some Imulsion up into the atmosphere of Sera, causing a condition known as Rustlung to spread through the remaining Human population.
  • The Timgad Valley, where the Lightmass Bomb was deployed, was home to the breeding grounds of the Kryll. The detonation of the Lightmass bomb destroyed the breeding grounds and killed virtually all of them, to the point where they are either extinct, or their numbers are too low to breed enough to ensure their survival as a species.
  • It's possible that the work on the Lightmass Bomb was similar to that of the Lightmass Missile given their similar design and purpose.


The Weapons and Equipment of Gears of War
Melee Weapons Chainsaw Bayonet · Combat Knife · Commando Knife · Machete · Powersaw
Rifles Designated Marksman Rifle · EMBAR Railgun · Enforcer Submachine Gun (Shock variant) · GZ18 Markza Sniper Rifle (Marksman variant) · Hunting Rifle · Musket · Longshot Sniper Rifle · Mark 1 Lancer Assault Rifle (Police variant) · Mark 2 Lancer Assault Rifle (Custom variant) · Mark 3 Lancer Assault Rifle (GL variant) · UIR Belt-fed Machine Gun
Shotguns Gnasher Shotgun · Overkill Shotgun · Sawed-Off Shotgun
Sidearms MX8 Snub Pistol · Talon Autopistol · Zapper
Grenades Beacon Grenade · Bolo Grenade · Cytostatic Gas Grenade · Flashbang · Incendiary Grenade · Molotov Cocktail · Shock Grenade · Smoke Grenade · Stim-Gas Grenade
Heavy Weapons Auto-Turret · Booshka Grenade Launcher · Buzzkill · Chain Gun · COG Machine Gun · Cryo Cannon · Dropshot Munitions Launcher · Laser-Guided Rocket Pod · Longspear Rocket Launcher · Mortar · Mulcher · One-Shot · Rocket Launcher · Salvo Rocket Launcher · Scorcher Flamethrower · Silverback Rocket Launcher · Stomper · Tripwire Crossbow · Tri-Shot Chain Gun · Twin-Barrel Turret · UIR Machine Gun · UIR Minigun · Ultra-Violet Turret · Vulcan Gatling Gun
Super-Heavy Weapons Asp SAM Turret · Ball Turrets · Brader · Defence Missile System · High Velocity Main Cannon · Flechette Guns · Fortress Artillery Cannon · Industrial Staple Gun · Kestrel Missile Launcher · Mega Mech Gatling Gun · Naval Gun · Pariah Cannon · Railgun · Torpedo · UIR Artillery Battery · UIR Anti-Air Turret
Weapons of Mass Destruction Hammer of Dawn · Imulsion Countermeasure Weapon · Lightmass Bomb · Lightmass Missile · Nuclear Missile · Venom Bomb
Equipment Adrenaline Injector · Barrier · Blow Torch · COG/UIR Ammo Crates · Cloak · COG Armor · COG Tag · Fire Extinguisher · Gas Mask · Gut-Puncher · Propane Tanks · Pulse · Remote Targeting System · Stim · UIR Armor · UIR Tag
Other Bow · Flash · Hijack · Shock Trap
Melee Weapons Butcher Cleaver · Breaker Mace · Combat Knife · Crystal Tooth Bayonet · Dual Chainsaw Staff · Explosive Flail · Serrated Knife · Staff · Tremor Hammer
Rifles Breechshot · Claw Light Machine Gun · Hammerburst Assault Rifle (Gorgon variant) · Hammerburst II
Shotguns Elite Sawed-Off Shotgun
Sidearms Boltok Pistol · Gorgon Submachine Gun
Grenades Bolo Grenade · Ink Grenade · Kryll Grenade
Heavy Weapons Boomshot Grenade Launcher · Canker · Digger Launcher · Multi-Turret · Nemacyst · Reaver Chain Gun · Torque Bow · Troika Heavy Machine Gun (RAAM's variant)
Super-Heavy Weapons Brumak Rocket Launcher · Wrist-Mounted Chain Gun · Brumak Rocket Mortar · Corpser Mine Layer · Hydra Missile Pod · Hydra Rocket Pod · Locust Defense Tower · Reaver Rocket Launcher · Siegebeast Catapult
Weapons of Mass Destruction Riftworm
Equipment Boom Shield · Imulsion Explosive Canister · Imulsion Injection Harness · Immune System Booster · Locust Ammo Crates · Locust Armor · Locust Emblem · Swarm Armor · Thumper · Torture Pod
Other Ticker
Easter Egg Weapons
Melee Weapons Elemental Cleavers · Fish Stick
Rifles A Real Gun
Shotguns Raging Buccaneer
Sidearms Despicable You · Memento Mori
Grenades Dom's Toms
Heavy Weapons Cluckshot · Trackshot
Other Relic Weapons