XCOM EW MECTrooper.png
XComEW MEC Trooper logo trans.png

The Mechanized Exoskeletal Cybersuit Trooper is a new soldier class introduced in XCOM: Enemy Within.

Those who volunteer for these procedures will sacrifice much, but they will receive a substantial increase in combat effectiveness.

Dr. Raymond Shen, XCOM: Enemy Within

XCOM Database[]

Soldiers at Squaddie rank or higher can undergo augmentation in the Cybernetics Lab to become MEC Troopers. They will gain access to new training options as well as the ability to deploy a MEC in combat. They will retain their ranks; however they will abandon their former classes in the process. MEC Troopers cannot enter battle unless they have a MEC equipped.

–XCOM Database, XCOM: Enemy Within

Class Creation[]

MEC Troopers are not generated at random during Rookie promotion like other class assignments, but are created by augmenting soldiers in the Cybernetics Lab. Rookies and Psionic soldiers are ineligible for augmentation.

Converting a soldier to a MEC Trooper is a permanent class change. They lose their abilities and Gene Mods, but retain their stats, rank and experience. MEC Troopers have stat growth similar to Heavies, so it may be preferable to postpone the conversion of other classes until at the highest rank possible is reached, but there are exceptions:

  • An assault at Colonel rank has 89 aim.
  • Heavies can and should be converted at any rank before Captain rank as it maximizes all attribute gains (Aim, Will, HP). The resulting soldier at Colonel will have 77 aim.
  • Snipers get large amounts of Aim per promotion, 105 total at Colonel, but only 8 HP to other soldiers' 9. Augmenting them at Major will result in one additional HP point in exchange for 8 Aim, although with a MEC Trooper's already large health pool, one single point tends to be irrelevant.
  • A support at Colonel has 90 aim.
  • With the "Hidden Potential" Second Wave option enabled, MEC Troopers have a gain of 1-5 Aim per promotion. This is much less than a Sniper (3-9) and inferior to a Support (2-6), but equal to an Assault and superior to a Heavy (0-2). As such, if a Heavy-based MEC is in the plans, it's best to augment the soldier as soon as possible for maximum accuracy gain.

As part of the augmentation process, soldiers replace their arms and legs with cybernetic limbs known as Base Augments. It costs §10 and Meld10 to transform a soldier into a MEC Trooper, and they are removed from active duty for 3 days while this takes place. It is possible to augment wounded soldiers, reducing their time out of action to only the time spent in the Cybernetics Lab. MEC Troopers remain human enough to be affected by Psionic abilities, including Mind Control, but cannot be genetically modified or undergo Psi testing.

Weapons and Equipment[]

MEC Troopers do not use the same weapons or equipment available to the other classes but instead utilize Mechanized Exoskeletal Cybersuits in combat. MECs grant MEC Troopers significant health and Will bonuses, access to heavy weaponry and advanced Tactical Subsystems, as well as immunities to fire and poison; they also gain the Hardened trait. MEC Troopers wear their Base Augments when outside of a MEC Suit.

MEC Troopers employ specialized weaponry:

Weapon Base Damage Crit Damage Crit Chance Range
Minigun  Minigun 4 - 6 8 - 10 10% Medium
Railgun  Railgun 6 - 8 11 - 13 10% Medium
Particle Cannon  Particle Cannon 9 - 11 15 - 17 10% Medium
Source: Tactical Info, XCOM: Enemy Within

In comparison to the standard rifles used by Rookies, Supports and Assaults, MEC Trooper weapons provide a +2 base damage bonus and a +4 Crit damage bonus. This effectively raises the MEC Trooper's weapon by one tech level (i.e. the damage output of the Minigun matches that of the Laser Rifle); their damage within a given tech level is surpassed only by the Sniper's Headshot ability, which is able to inflict comparable critical damage to targets, but with much greater frequency.

Abilities / Upgrades


Upon undergoing augmentation, MEC Troopers gain a special inherent ability based on their previous class:

Class Abilities Description
XEU ClassAssault.png
Assault Class
Shock-Absorbent Armor Icon.png Shock-Absorbent Armor Damage received from enemies within 4 tiles is reduced by 33%.
XEU ClassHeavy.png
Heavy Class
Body Shield Icon.png Body Shield The nearest visible enemy suffers -20 Aim and cannot critically hit this unit.
XEU ClassSniper.png
Sniper Class
Platform Stability Icon.png Platform Stability Any shots taken without moving have +10 Aim and +10% critical chance.
XEU ClassSupport.png
Support Class
Distortion Field Icon.png Distortion Field Nearby allies in cover receive +10 Defense.

Additionally, MEC Troopers gain experience and ranks conventionally and have their own unique training tree:

Rank Abilities Description
Collateral Damage Icon.png Collateral Damage An area of effect attack that destroys most cover and hits all eligible targets for 34% damage. This attack cannot cause critical hits.
XComEW Advanced Fire Control icon.png Advanced Fire Control Shots from Overwatch no longer suffer any Aim penalty.
Automated Threat Assessment Icon.png Automated Threat Assessment Confers +15 Defense when in Overwatch.
XComEW Vital-Point Targeting icon.png Vital-Point Targeting Confers +2 Damage against all humans and autopsied aliens.
Damage Control Icon.png Damage Control When a MEC takes damage, all further damage will be reduced by 2 for the next 2 turns.
Jetboot Module Icon.png Jetboot Module When activated, confers the ability to jump to normally inaccessible heights for the rest of the turn.
XComEW One For All icon.png One For All When activated, the MEC becomes a high cover element. Moving or using an arm-based weapon will return the MEC to standard posture.
XComEW Repair Servos icon.png Repair Servos Confers 2 health recovery at the start of each turn. A total of 6 health can be regenerated per battle.
Expanded Storage Icon.png Expanded Storage Allows additional use of Restorative Mist, Grenade Launcher and Proximity Mine Launcher in each mission. Increases primary weapon base ammo by 50%.
Overdrive Icon.png Overdrive Firing the MEC's primary weapon as the first action no longer ends the turn.
XComEW Absorption Fields icon.png Absorption Fields Any hit that does more damage than 33% of the MEC's maximum health is reduced to that number.
XComEW Reactive Targeting Sensors icon.png Reactive Targeting Sensors The MEC gets a free shot back at the first enemy who attacks the MEC each turn, provided there's enough ammo to do so.


When equipped with a MEC Suit, MEC Troopers gain the following trait:

Trait Description
Hardened.jpg  Hardened  Hardened units receive 60% extra protection against critical hits.

Ability Comparisons[]

MEC Troopers have the most complex skills and customize builds of any soldier class.

Inherent Ability[]

MEC Trooper skills should complement their inherent ability for a common purpose.

  • Shock-Absorbent Armor for flanking and close-quarter rushes.
  • Body Shield for tanking and mid-range firefights.
  • Platform Stability for ambushes and long-range sniping.
  • Distortion Field for supporting rigid squad formations.

Advanced Fire Control vs. Automated Threat Assessment[]

Advanced Fire Control is preferred for most cases, and Automated Threat Assessment only in conjunction with Body Shield.

  • Advanced Fire Control is functionally identical to Opportunist (without the critical damage).
    • Advanced Fire Control's reaction fire often kills weaker foes attempting to outflank or run away in one hit.
  • Automated Threat Assessment increases Defense to 15 while on Overwatch.
    • Body Shield reduces the nearest enemy's Aim by 20, granting a total defense of 35 in regard to that unit only
    • Automated Threat Assessment ends if the MEC Trooper takes an Overwatch shot, further reducing its utility.
    • Automated Threat Assessment works best with Kinetic Strike Module when MEC Trooper falls short a few tiles of an alien in full cover; or in situations where a normal shot would most likely miss.

Vital-Point Targeting vs. Damage Control[]

Damage Control is preferred for most cases, due to AIs preference for targets with a high hit probability leading resulting in MEC Troopers often drawing enemy fire.

  • Damage Control effectively grants MEC Troopers 4-6 health per turn in Firefights.
    • Damage Controls mitigation comparatively prolongs a MEC Trooper's lifespan. On higher difficulties this is a marginal amount; two consecutive hits from a Thin Man's 6-9 damage range kills a Level 1 MEC.
    • Damage Control can be very powerful when combined with Absorption Fields. A 15 hit point Warden will take a maximum of 4 damage per hit due to Absorption Fields, subsequently reduced to a maximum of 2 damage per hit with Damage Control. A Warden starting with 15 hit points will therefore require a minimum of 7 hits to kill (at least until Damage Control wears off), making them very rugged.

Jetboot Module vs. One For All[]

Jetboots is preferred for most cases, as clustered units will trigger AI's grenades and Area of Effects.

  • Jetboots can be used to reach high ground and grant good fields of fire over the map.
    • Jetboots and Kinetic Strike can quickly close distances with the enemy by moving straight over normally impassable terrain.
  • One for All is functionally identical to Alloy S.H.I.V.'s Armored Shell ability.
    • One For All ends if the MEC Trooper takes an Overwatch shot, moves, or uses any other low-tier abilities, further reducing its utility.
      • High-tier abilities do not cancel the effect.

Repair Servos vs. Expanded Storage[]

Expanded Storage is preferred for most cases, due to superior utility and healing options.

  • An exception is for Kinetic Strike MECs on Impossible, where Repair Servos allow an aggressive MEC to repair on the move, reserving turns for useful action.
    • Restorative Mist will still be taken for healing potential and total hp as Grenade Launcher is much less effective on Impossible. There is no difference in the amount of self-healing compared to 2x Restorative Mist if the MEC has not been awarded the Defender's Medal.
      • If the MEC has been awarded the Defender's Medal, the difference is 2 hp.
    • An aggressive Kinetic Strike MEC makes many kills with Kinetic Strike throughout the game from beginning to end and makes much more use of Electro-Pulse than Proximity Mine Launcher, and thereby the other needs for Expanded Storage are negated.
  • Repair Servos effectively grants MEC Troopers 4-6 health per mission.
    • Repair Servos, by itself, is inferior to Damage Control, Restorative Mist and Savior Support.
      • Expanded Storage + Restorative Mist heals 4 per use for two uses, for a total of 8 points of healing.
      • Restorative Mist heals in a small AoE instead of just healing the MEC.
        • Restorative Mist requires an action to use, as opposed to Repair Servos, which is passive.
    • Repair Servos should only be taken if no other viable healing options are available, and only in conjunction with MEC Troopers defensive skills.
  • Expanded Storage Increases MEC Troopers' primary weapon base ammo by 50%, and allows 1 additional use of Restorative Mist, Grenade Launcher and Proximity Mine Launcher in each mission.
    • Repair Servos might be preferable for Grenade Launcher MEC Troopers for a balance of healing and offense.

Absorption Fields vs. Reactive Targeting Sensors[]

Reactive Targeting Sensors is preferred for most cases, due to MECs having very high health pools and the Hardened trait; Absorption Fields only if in conjunction with Body Shield.

  • That being said, this changes on Impossible, where Absorption Fields are the way to go unless you like relegating your star MEC to a secondary role.
  • Absorption Fields effectively reduces incoming damage to 33% of MEC Trooper's maximum Health.
    • Absorption Field is comparable to the Assault's Resilience ability
    • Absorption Fields' threshold damage reduction, prevent all damage above a certain threshold, while having no effect on damage below that threshold.
      • Absorption Field scales backwards; its usefulness gradually decreases as the MEC Troopers' HP bar increases.
        • Absorption Field is vital to the survival of a brand-new MEC-1.
        • Absorption Field is useless to the survival of a fully upgraded MEC-3.
      • Absorption Field contributes weird occurrences such as a Sectopod hitting a baseline MEC for 4 damage with a cannon that can normally deal 15 damage.
    • Absorption Field almost never applies itself on difficulties below Impossible, as on average, only Sectopods deal more than 33% of a MEC Trooper's health (without critical damage).
  • Reactive Targeting Sensor effectively provides a free shot during the MEC Troopers' turn, provided there's enough ammo to do so.
    • Reactive Targeting Sensor depletes ammo fast, often against insignificant targets with a very low probability of connecting return fire.
    • Reactive Targeting Sensor shot has normal reaction shot penalty (confirmed by missing on shot that has 100% accuracy after enemy's turn), therefore it has no synergy with Advanced Fire Control.
    • Reactive Targeting Sensor's synergy with the Aim bonuses Platform Stability are currently unknown.

Builds & Tactics[]

Main article: Squad Tactics (XCOM: Enemy Unknown)

Ultimately, a MEC Trooper should be built to suit the player's play style and complement the abilities of the squad. A MEC Trooper built in the early game can still be trained in a way so that it can be effective late game. An understanding of the capabilities of the player's squad and the various builds and abilities of MEC Troopers is required before choosing any build.

Engaging Psionic Enemies

Players should be careful with their MEC(s) when fighting psionic foes (Sectoid Commanders, Ethereals) who possess the Mind Control ability. MEC Troopers have no pistol option to switch to, and pack a lot of firepower. Thus, having a Mind Controlled MEC is a highly dangerous proposition, and is made all the more possible by the fact that they cannot equip Mind Shields or be gene modded with Neural Damping. Thus, it may be advisable to augment soldiers with high Will to make Mind Control more difficult.

When a MEC Trooper is at high risk of being Mind Controlled, there are the options of emptying the MEC's primary weapon using Collateral Damage or simply firing at the psionic enemy in question, to deprive the MEC Trooper of some offensive options should it be mind controlled. It may be easier if MEC Troopers simply remain near the Squad Leader (preferably Psionic coupled with Lead By Example) and out of a psionic enemy's Line of Sight until ready to dash in for a kill. The problem can be mitigated by choosing a higher will soldier (above 100) to Augment into a MEC. Then, even if Mind Control is attempted, it would usually fail. It is also highly advised - if not, mandatory - to have a psionic soldier who has Psi-Inspiration to inspire them to further reduce or nearly eliminate the chances of being Mind Controlled.

MEC Squad Leader

Using Shaojie Zhang, it is possible to create a very high Will MEC Trooper that exploits Lead By Example. Example: 16 (Iron Will OTS) + 90 Will (Colonel base) + 20 Will (MEC-3 Paladin bonus) = 126 Will total will be boosted for other soldiers.

Warden Tanking

Absorption Fields ability seems dubious due to the high HP of MECs, but it is very powerful when combined with Damage Control, Repair Servos, a MEC-1 Warden and 6-HP Colonel MEC Trooper. Do not research Shaped Armor. Since this build is intended to deal with late-game heavy hitters - especially the dreaded Sectopod - the Kinetic Strike Module is more useful than the flamethrower. Without Hidden Potential, the only way to get a 6-HP colonel is to use a sniper in Impossible difficulty. A Sectopod's accompanying Drones can damage the Warden faster than the Sectopod itself can, so either capture or eliminate these nuisances quickly.

Sniper MEC Trooper[]

Use a Sniper as the MEC Trooper base:

Platform Stability, Advanced Fire Control, Vital-Point Targeting, Jetboot Module, Expanded Storage, and Reactive Targeting Sensors
Flamethrower, Grenade Launcher and Proximity Mine Launcher
Advanced Servomotors, Jellied Elerium, Shaped Armor
MEC Trooper jetboots to high ground with good fields of fire, and remains stationary while firing explosives. Overdrive allows your main weapon to fire twice, with two bonus damage per shot and 10% extra hit/crit chance. Overwatch accuracy is also boosted, along with giving it free reaction fire to a target that fires back.
The Flamethrower Module with the Absolutely Critical Second Wave option enabled guarantees 9 base damage to enemies, which can be upgraded to 13 by Jellied Elerium.

Assault MEC Trooper[]

Use an Assault as the MEC Trooper base:

Shock-Absorbent Armor, Advanced Fire Control, Vital-Point Targeting, Jetboot Module, Expanded Storage, Absorption Fields
Kinetic Strike Module, Restorative Mist, Electro Pulse
Advanced Servomotors, MEC Close Combat, Shaped Armor
MEC Trooper rushes close-quarters with either Kinetic Strike or Electro Pulse, and primarily uses its main weapon, firing twice per turn, while still getting a (3rd) free reaction shot. The MEC will have incredible mobility, improved ammo storage, and the ability to stun Sectopods and kill Sectopods and Mechtoids in one turn. Everything about this build is oriented toward late-game dominance.
The Kinetic Strike Module with the Absolutely Critical Second Wave option enabled guarantees a critical hit every time. The punch does 18 damage, which can be upgraded to 27 with two uses per turn by MEC Close Combat.

Heavy MEC Trooper[]

Using a Heavy as the MEC Trooper base:

Body Shield, Automated Threat Assessment, Vital-Point Targeting, One For All, Expanded Storage, Reactive Targeting Sensors
Kinetic Strike Module, Grenade Launcher, Electro Pulse
Advanced Servomotors, MEC Close Combat, Shaped Armor
MEC Trooper is optimized for early game dominance. The defense abilities allow this MEC to avoid and/or shrug-off early game attacks with impunity. The area-based attacks are enough to kill or cripple most early and mid-game enemies. However, late game (even with upgrades), the player will find both this MEC's damage and defense options waning when compared to alternatives.
The Kinetic Strike Module with the Absolutely Critical Second Wave option enabled guarantees a critical hit every time. The punch does 18 damage, which can be upgraded to 27 with two uses per turn by MEC Close Combat.

Support MEC Trooper[]

Using a Support as the MEC Trooper base:

Distortion Field, Automated Threat Assessment, Vital-Point Targeting, Jetboot Module, Expanded Storage, Reactive Targeting Sensors
Flamethrower, Restorative Mist, Proximity Mine Launcher
Advanced Servomotors, Jellied Elerium, Shaped Armor
MEC Trooper supports allies by provoking enemy fire. Nearby allies should be in cover and distorted. Concentrate fire on higher threat targets, while leaving the MEC's squadmates to take care of the weaker enemies before aiding the MEC. Only use this MEC if you need a tight squad. You will be able to take out Chryssalid "Zerg rushes" with flamethrowers.
The Flamethrower Module with the Absolutely Critical Second Wave option enabled guarantees 9 base damage to enemies, which can be upgraded to 13 by Jellied Elerium.


  • MEC Troopers earn half the regular experience for kills.
    • It is advantageous to pick the highest-ranked soldier for the augmentation procedure (Colonel if possible), otherwise the leveling up process can take almost twice the usual time
    • The high damage weapons and AoE Subsystems available to MECs often allow MEC Troopers to rack up multiple kills quicker/easier during a mission, especially in the early game, which works to offset this handicap.
  • MEC Troopers gain no benefit from cover.
  • MEC Troopers cannot open 2 tile shutter doors, nor open doors silently; they just bash through them.
  • MEC Troopers are healed by Medikits, Arc Throwers upgraded with S.H.I.V. Repair, and the Repair ability of captured Drones.
  • MEC Troopers cannot equip items (S.C.O.P.E., Mind Shield, etc). They rely instead on the MEC's subsystems.
  • Former Heavies will have the least aim when optimized, probably due to the fact the class relies on their kit more than other soldiers, while the Sniper has the most, probably because elements of their kit are an active impediment.
  • With Hidden Potential enabled, MEC Troopers have the same 1–5 Aim gains per rank as Assaults. As such, it may be better to augment low-rank Heavies.


  • "Bellator in Machina" is Latin for "Warrior in the Machine".
  • The in-game XCOM Database specifies that "the augmented MEC metal skeleton was designed so that soldiers could perform typical, regular-life tasks once the war was over to regain a semblance of normal life."
    • MEC Trooper users can see augmented soldiers occasionally running on the treadmills, if zooming into the Barracks from the "ant farm" view. While this may seem like a "pointless typical, regular-life activity" (as such physical exercise would only increase the maintenance requirements on mechanical components), it possibly serves to promote camaraderie and morale. It could also be that skillful use of the augments requires practice, acclimatization, and/or calibration.
    • Augmented soldiers can be seen occasionally going through eating motions at the bar, if zoomed into the Barracks from the "ant farm" view. This implies augmented troopers either retain digestive function, or steps were taken to allow augmented soldiers to eat for social reasons. As the process is described as primarily involving the amputation of limbs along with implanting of cybernetic interfaces, it is likely they still have most of their vital organs, and require food to maintain their biological tissue (although caloric requirements would probably be significantly reduced without the need to maintain limb muscle mass).
  • MEC Troopers use a different set of voices (2 per gender), all emotionless, deeper, filtered ("robotic") and using more formal lexicon. The exception is unique characters such as Zhang and Annette, who keep their original voices.
  • MEC Troopers' reaction shot takes less ammunition that regular shots. It takes little less than 66% of ammunition of standard shot in early game and less than 50% of ammunition in late game. It needs verification.