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Mass Effect Wiki

The CAT6 Heavy is a CAT6 unit encountered in Mass Effect 3 Citadel DLC.



The CAT6 Heavy is equipped with an M-76 Revenant Light Machine Gun which deals high damage and is capable of sustained fire. In melee range, Heavies will swipe with their shield or their weapon. They also possess a special combo attack at close range where they slam their shield down causing a shockwave that will stun nearby targets, immediately followed by a lethal barrage from their rifles. Without their shields, Heavies will use stun batons to melee, but unlike the CAT6 Specialist, they can be staggered by light stun effects during the baton's melee animation.


CAT6 Heavies have heavy armor and can generate large ballistic shields that are similar in function to the kind wielded by Cerberus Guardians, though they are tech-based and can be destroyed by Energy Drain, Overload, and Sabotage, as well as Pull. They can take cover, but don't need to while their shields are up. Like most other infantry enemies in Mass Effect 3, they can be staggered by gunfire or powers, and they take 40% additional damage from headshots.


  • Their Revenants allow Heavies to attack from medium range. When coupled with their ballistic shields, Heavies can box Shepard in while their allies attack from afar.
  • Omni-shield: Like the Cerberus Guardian, the Heavy carries a large "riot shield" that is its main advantage in battle:
    • While their shields are active, a Heavy is essentially immune to many powers, debuffs, and weapons fire, though this is directional protection; if they can somehow be flanked or hit from an angle not covered by the shield, they are still vulnerable. Reave is an exception and will hit a Heavy through the shield.
    • A Heavy's shield can be yanked away or destroyed by certain powers or if it takes enough damage from weapons, but it will regenerate if the Heavy is left alone for a period of time.
    • A Heavy's shield can be yanked away with Pull; though Lash will remove a Guardian's shield, it does not remove a Heavy's.
    • Heavies are immune to Dark Channel while shielded, including the spread-on-death effects, i.e. a nearby Dark Channeled enemy that dies can't spread it to them.
    • In contrast to a Guardian's shield, the shield wielded by the Heavy appears to be at least partially energy-based and can be destroyed by tech powers. Overload, Energy Drain, and Sabotage will all destroy the shield and cause feedback that electrocutes the Heavy, stunning it for a decent period.
    • Like with a Guardian's shield, there is a "mail slot" to take advantage of, however, Heavies are armored even under the shield, so not only must a weapon have higher than average combined penetration value to hurt the Heavy effectively through the shield, but headshots through the slot won't be as effective as they are versus Guardians.
    • Singularity is not able to lift Heavies or remove their shields but it will stagger them periodically as long as they remain within the vortex. The Rank 6 Detonate evolution can hurt them while shielded, and it can even detonate a Biotic Explosion on a shielded Heavy as long as the Heavy was primed for a biotic combo when the Singularity detonates and the Heavy is in the Singularity field. Reave is the only biotic power that can prime a Heavy for a biotic combo while its shield is up.
  • Even without their shields, Heavies are still armored and can't be frozen, lifted or knocked down by force-based powers, or affected by Stasis. They can, however, be staggered by various powers and weapons even while their shields are up, sometimes enough that the shield is displaced, leaving them more vulnerable to weapon fire until they recover. Charge and Nova are capable of inflicting these heavier stuns.
  • The M-98 Widow, Black Widow, Javelin, N7 Crusader, N7 Typhoon, and Executioner Pistol all fire penetrating rounds by default that suffer no damage penalty for hitting targets through other objects. The Javelin's default thermal scope nicely highlights its targets through cover, making lining up headshots simple.
    • Piercing weapon mods can be used on most other standard bullet-firing weapons to penetrate a Heavy's shield, but this will result in a damage penalty for hitting through objects. However, the above listed weapons that pierce by default are exempt from this. All weapons suffer a piercing penalty of 50% if Armor-Piercing Ammo is active.
    • The Chakram Launcher, Geth Plasma Shotgun, and the Kishock Harpoon Gun can penetrate their shields without the aid of any piercing mods with no penalty. However, unlike when it is used against Cerberus Guardians, the Kishock appears to suffer a damage penalty when shooting through the Heavy's shield, even though it normally does not suffer any damage penalty against armored targets. The other two weapons suffer no penalty for striking armor, making them highly effective against Heavies.
  • The charged shots of the Venom Shotgun make short work of Heavies, shielded or not.
  • Grenade powers will hurt Heavies if they detonate behind the shields or are able to hit a gap in the shields from the front, though the latter is basically luck.
  • Heavies can climb ladders, with or without their shields.