Soldiers are your most important and valuable unit in Enemy Unknown 2012 and their death on the battlefield is permanent. Soldiers have distinct classes and their status can be checked at XCOM HQ's Barracks facility, where you can also hire new soldiers. They can be equipped with the latest available armor, weapons and other equipment. XCOM soldiers may also be assigned to the Officer Training School in order to progress in rank and gain specific squad abilities. It is also possible to customize your soldiers' name, nickname and physical appearance.
You may increase your combat troops through the following:
- By hiring them through the Barracks facility (and sacking them as well).
- By receiving soldiers of specific class/rank (will be one rank below the highest-ranked soldier you already have for that class) as a Council reward for the completion of specific combat missions. You get to select how they skill up.
- Special cases are Zhang in Slingshot and Annette and 'The Furies' in Progeny.
- Finally there are also 'XCOM heroes' - those are beefed up soldiers you can unlock as an Easter Egg but unlocking will disable the achievement score.
Point on flag for country name.
Poland has replaced Saudi Arabia on the Enemy Within DLC.
All soldiers start as rookies with their class being only revealed after he/she is promoted to Squaddie and have their stats upgraded according to their class. Each class has unique abilities, and will receive specific stat bonuses upon promotion but will also have specific stat limitations and/or restrictions on weapons/equipment they can carry. Generally, each promotion will require you to choose from one of two perks available to the class at that rank.
|Class||Description||Move and Fire||Firepower||Aim||Critical Hit Chance||Primary Ability||Primary Weapon|
|Basic unit||Yes||Normal||Normal||Normal||None||Assault Rifle|
|Close combat unit||Yes||Normal||Normal||High||Run & Gun|| Shotgun|
|High-caliber and explosive firepower||Yes||High||Normal||Normal||Rocket Launcher||LMG|
|Long-range accurate fire||No||Normal||High||High||Headshot||Sniper Rifle|
|Jack of all trades||Yes||Normal||Normal||Normal||Smoke Grenade||Assault Rifle|
|Armored unit||Yes||High||**||**||Collateral Damage||Minigun|
* Psionic class is a sub-class build from existing soldiers so it's stats will be based on the starting class.
** MEC Trooper is a new class introduced in the Enemy Within DLC. MECs can be made from any existing class and they have a passive ability based on its former class.
Further information about each class may be found on the Classes page.
Each soldier also has a rank, starting as a rookie. As he/she progresses through the ranks, the soldier gains additional combat abilities and stat bonuses. Attaining certain officer ranks unlocks improvements that can be purchased through the Officer Training School (first available at Sergeant). Each class receives specific stat bonuses upon each rank-up: Abilities, HP, Aim, and Will. Newly-hired Rookies' stats start at the following base values:
With the Second Wave option Not Created Equal, all soldiers will have Will scores between about 25 to 59, Aim of 50 to 80 and 11 to 14 Movement scores.
Once a rookie is promoted, they then get the following stat bonuses:
In addition to the fixed stat bonuses above, there is a random 0-4 bonus for willpower at each level. If the Iron Will upgrade was purchased at the OTS, another 2-6 willpower can be gained on top that too.
With the Second Wave option Hidden Potential (and the Iron Will purchase), all classes can potentially get Will gains up to 13 points, and different/random HP, movement and Aim gains (except for heavies, which will always get little to no Aim gains).
In order to progress in ranks a XCOM soldier has gain experience points (XP) up to a certain level. Experience points can be gained by killing aliens (with the higher species worth more points) and by completing missions. It is also possible to purchase the Wet Work ability from the Officer Training School, which gives an additional +25% points gained from kills.
|Rank||Points Required||Points Required (EW DLC)|
* After their Gift being revealed on the Psi Lab, Psionic soldiers are required to perform specific Psionic actions to be promoted.
|Resist Psi Attack||10**|
|Successful Mind Inspiration||30**|
|Assist Mind Inspiration||30**|
|Successful Psi Panic||30**|
(**) Psionic actions.
Source: XComGame.upk\XGTacticalGameCore, originally posted here 
Enemy Within Supplemental
- MEC soldiers gain only 50% of the normal experience points received through kills.
- The Star of Terra medal gives also a +25% bonus increase on experience gain from completing a mission, if the soldier's rank is below Lieutenant.
- Vehicles blowing up and killing aliens are credited to the soldier who set the vehicle on fire. As this is entertaining, more research is needed to determine if it is only the first soldier that hits a vehicle who gets credit for the fire-kill, or if it's the last soldier to hit the vehicle, or even multiple credit can be gained.
- Covert Operations missions seem to give extra XPs to the Covert Operative, although the mechanic is still unknown.
- According to reports, the higher alien ranks don't give the double XPs as they did before, although it is unknown what are the new conditions.
- Soldier can choose between two specific class abilities upon promotion (exclusively).
- Purchased through the Officer Training School (require presence of high rank officer(s)) .
- Equipment, research, and upgrades may also provide additional abilities for your squad.
|XCOM: Enemy Unknown (2012): XCOM Units|
|Soldiers:||Assault • Heavy • Sniper • Support • Psionic • MEC Trooper (EW DLC)|
|S.H.I.Vs:||S.H.I.V.• Alloy S.H.I.V. • Hover S.H.I.V.|
|Attributes:||Classes • Class Builds • Abilities • Stats • Nicknames • Gene Mods (EW DLC) • Medals (EW DLC)|
|Loadout:||Weapons • Armor • Equipment • MEC Suit (EW DLC)|
|Barracks:||Officer Training School • Psi Lab • Memorial • Genetics Lab (EW DLC) • Cybernetics Lab (EW DLC)|
|Other:||Volunteer • Heroes • Zhang (Slingshot DLC) • Annette (EW DLC) • Covert Operative (EW DLC) • Training Roulette (EW DLC)|