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Mass Effect Wiki
Disambiguous This article is about the heavy weapon in Mass Effect 2 and Mass Effect 3. For the power in Mass Effect 3's multiplayer mode, see Cain Trip Mine.

The M-920 Cain is a heavy weapon in Mass Effect 2 and Mass Effect 3.

Mass Effect 2[]


The effectiveness and efficiency of mass-effect-based weapon technology has rendered large-scale deployment of highly explosive weaponry all but obsolete in infantry weapons.

Normandy's scientists have prototyped a modified version of traditional high-explosive rounds that is applied to a 25-gram slug. When accelerated to 5 km/s, the round is devastating. Though a technically inaccurate label, this prototype weapon is nicknamed the "Nuke Launcher," and its high-explosive matrix generates an archetypical mushroom cloud on impact.

Inflicts high damage with a large area of effect. Very effective against armor, shields, and barriers.


Unlocked at the Normandy research station after three Heavy Weapon Ammo upgrades have been researched. Costs 25,000 iridium.

Player Notes[]

  • On Normal difficulty, the M-920 Cain is capable of killing enemies within an extremely large area in a single shot. The Thresher Maw on Tuchanka, the Oculus, and the final boss are the only enemies in the game that the Cain cannot kill instantly; instead, the Cain takes off a little more than half of each enemy's health bar. On Insanity difficulty, A-61 Mantis Gunships, Praetorians, YMIR Mechs and the Geth Colossus also will not die in one hit, though each will have very little armor remaining.
  • The Cain does cause damage to Shepard and the squad, though somewhat strangely it's rarely lethal even at point-blank range unless you've already taken damage. Regardless, the large blast radius means care should be used when targeting.
  • The Cain's blast is capable of damaging enemies through intervening cover and terrain such as walls, one of only two weapons in Mass Effect 2 that can do so, the other being the M-490 Blackstorm.
  • Gathering all the heavy weapon ammo you can find will generally allow the Cain to be used once every other mission. However, the Cain can only be fired when its ammo count is at 100% or above, meaning that it can only hold enough ammunition to be fired twice (full ammo upgrades, a 10% ammo bonus from armor, e.g. from the Cerberus Assault Armor set or the Ordnance Packs sold at Harrot's Emporium, bring its maximum capacity to 215%, or two shots). Shooting the Cain twice in succession will cause it to skip the usual charge time to fire the second shot.
  • The explosion from a Cain shot causes a brief time dilation effect similar to the one caused by the Adrenaline Rush power.
  • After five Heavy Weapon Ammo upgrades the ammo will sometimes "refill" automatically after each mission you use it on provided it is equipped at the end of the mission, however, it only fills up to 100%.
  • The Cain's limited capacity and high ammo expenditure make it a poor choice for general use in most missions; usually the Cain should be equipped for use on a specific hard target that's tough to take down through other means. Pre-planning where you want to use the Cain is useful to ensure you don't accidentally use up too much heavy weapon ammo leading up to those encounters.
  • Although the game claims that the slug is sped up to 5 km/s, the actual projectile in game moves very slowly compared to other weapons. This can actually make it difficult to hit enemies that move and dodge a lot, such as the final boss.
  • Charging the Cain while clinging to cover will cause Shepard to pop out of cover. With a four second charge time, this can mean certain death if you aren't careful, especially on harder difficulty settings. This can be compensated for by standing behind a tall piece of cover without sticking to it, charging the shot, and then moving out from behind the cover just long enough to fire the shot, then ducking back in.
  • The automatic Aim Assist feature in Mass Effect 2 does affect the Cain's shots, and unfortunately, will often do the opposite of assisting you to land a shot where you want it to go. Aim Assist is stronger on lower difficulties and depending on your settings; the only way to totally prevent it from potentially altering the trajectory of your shots is to fire when no enemy is "highlighted" in the HUD (i.e. you can't see any enemy's name and hitpoint bars).

Mass Effect 3[]


The M-920 Cain is a portable particle accelerator surrounding an array of dust-form element zero chambers. By subjecting its eezo chambers to extreme positive and negative currents fueled by antimatter reactions, the weapon projects mass effect fields that shear away at the target. The fields warp ambient materials with such explosive force that the impact produces a mushroom cloud. This has led Alliance marines to call the Cain a "nuke gun," though its detonations do not in fact produce fallout.

The M-920 uses graphite rods as neutron moderators, but they require frequent replacement to sustain power. Fortunately, the omni-tool can refabricate most heavy weapon ammunition into graphite rods. The amount of charge-up time is understandable as the weapon is a juggernaut capable of unstoppable destructive power.


  • Single-player: Two can be found near the crashed shuttle during Priority: Earth.
  • Multiplayer: N/A

Player Notes[]

  • After using the Cain to destroy the Hades Cannon, it is possible to use the spare copy of the weapon against the Reaper forces that bar your route to the shuttle. The weapon is still effective against these opponents. The magnitude of the explosion is considerably less impressive, but no less lethal.
  • Like its Mass Effect 2 counterpart, the M-920 Cain can kill your party and potentially Shepard if the blast is close enough. However taking squadmates down with this is usually not an issue since the Cain will reliably clear the field of other enemies in doing so allowing for near spontaneous revivals.


The M-920's Slug
  • The M-920 Cain is the only heavy weapon available for research in Mass Effect 2 that does not unlock a Codex entry in the Xbox 360 and PC versions of the game. In the PlayStation 3 version as well as the Mass Effect Legendary Edition, however, the entry is accessible.
  • The Mass Effect 3 Cain model is considerably smaller than its Mass Effect 2 iteration.
  • The M-920 Cain is not named for the Biblical Cain, but for Fallout and Fallout 2 designer Tim Cain.[1]
  • Although not a nuclear-based weapon, the M-920 has the radiation trefoil on the sides.

See Also[]