Officers are regular soldiers who have received additional training and responsibilities as leaders in the field for XCOM operations. Best used as formal leaders for specific recurring squads, Officers grant important tactical and strategic bonuses for those soldiers, some of which improve the more missions those squad members go on. Bear in mind that only one Officer at a time can serve as a mission leader (the highest ranking Officer, highest combat rank if tied, or highest Will if both ranks are tied); other officers on that mission do not have access to their special abilities.
Even the lowest ranking officer gets access to the powerful "Command" ability, which allows them to grant any ally an additional action at the cost of their own action, as well as the "Intervention" ability, which exchanges your Intel resource for an extension of the mission timer. Well-employed, Officers improves the reliability and survivability of your squad even in the face of unknown, unexpected, or inconvenient factors. There is some selflessness inherent to the Officer's duty, and use of many of their abilities will cost you opportunities to employ their combat skills at the same time, so make sure the squad you assign them to shores up the officer's blind spots that emerge from use of their special abilities.
A few important notes:
-Many officer abilities refer to the "Command Range" of an officer; this is an area of effect centered on the officer, inside which these abilities apply, and outside which they do not. The higher ranking the Officer, the larger this area. You can check this ability by pressing the green button on the upper right corner of the command screen, which toggles the display of this area.
-Officers are better than non-officers at rooting out Faceless spies when assigned to Haven Advisor duty. The higher the rank, the stronger this effect.
Training and Abilities
Officers can be trained via the Guerrilla Tactics School, and are unavailable for the duration of the training period (4-12 days depending on level) unless the training is cancelled. Once initially trained, all Officers are automatically granted the following perks:
This officer provides bonuses to will, dodge and infiltration to soldiers who have previously served under his or her command. These bonuses scale up the more missions they go on together.
End your turn to grant a bonus action to any visible member of the squad. The number of charges is dependent on the officer's rank.
Activate this ability to spend 10 intel and gain two turns on the current mission timer. The number of charges is dependent on the officer's rank.
Pistol shots against allies who have been mind-controlled by enemies have +50 to hit, cannot be dodged, and automatically kill the target if a hit occurs.
Pass a spare pistol to a civilian ally.
Officers can gain the following abilities as they rank up. An officer's rank increases as their normal level does. Each new ability must be trained by spending time in the Guerrilla Tactics School.
Spend an action to give all allies within Command Range +5 Mobility for the remainder of the turn. Usable once per mission.
Spend an action to pinpoint a target and grant your squad cumulative Aim bonuses and 1 Armor Piercing on attacks against that target for the rest of the turn.
Activate this ability to grant everyone within command range four points of damage resistance against explosive attacks through the end of the next alien turn.
Twice per mission, spend an action to grant all allies within Command Range a +20 bonus to Critical Hit chances for the remainder of the turn.
Grant a free but uncontrolled defensive action to any visible ally who has used all their moves.
Once per battle, delay the arrival of incoming enemy reinforcements by one turn.
The Officer improves the Aim, Will and Hack of soldiers within Command Range by half the difference between soldier and Officer.
Any kills of a non-human enemy by the squad have a 33% chance to grant 1 intel point as long as the Officer is healthy.
All allies within Command Range of the Officer gain +10% to hit on reaction fire.
Soldiers within Command Range of the Officer receive +5 bonus to defense value provided by cover.
The Skyranger will arrive 2 turns sooner during evacuations.
The officer's squad will infiltrate enemy targets more quickly.
All allies within Command Range of the Officer do +1 damage with all successful attacks.
Mission rewards of supplies, Alien Alloys and Elerium increased by 30% after successful missions. Squad members have a chance of collecting extra Alien Alloys and Elerium from aliens.
Candidates for Officer Training
Any soldier class (including Psi Operative) can receive officer training once they are no longer a Rookie. Here are some notes on class suitability for the role:
Ranger: Good. Rangers have access to a variety of defensive perks that can make your officer hard to kill in a fight, and their tendency to already serve in the mid and back lines means that they're usually well-positioned to catch everyone in their command range and line of sight. You will usually want to favor passive or free action abilities in this officer's training; "Fall Back" and "Incoming" are two good choices.
Assault: Poor. The Assault role is a hazardous job, especially reliant on actions and mobility, and managing the hazards your officers have to deal with is important to keeping them alive.
Gunner: Situational. Often times you'd rather have the gunner shooting than barking orders, especially if they're applying shred to tough targets. That being said, if your squad is already loaded in firepower and cover-busting effects, a SAW-specced Gunner can double as an officer without too much trouble. Like the Ranger, passive and free action abilities are ideal if you want to keep your damage output up.
Technical: Good. Technicals have access to the largest number of concurrent defensive perks in the game, so even if you're rushing them forward to flamethrower the enemy, the combination of Formidable, Burnout, Fortify, and Tactical Sense will make your Officer an unappealing target. Also, since the Technical's trademark weapons are already charge based, doubling them as your officer increases their utility and gives them things to do when heavy weapons are unsuitable for the task at hand.
Shinobi: Excellent. Officer abilities do not break concealment when used, allowing you to keep a forward observer Shinobi relevant without breaking their stealth, or simply retain the officer's stealth during a firefight for use later in a mission. An Officer Shinobi is also the vital half of the Shinobi-Specialist one-two punch that can effortlessly tackle most hacking and prison-break missions, using their Command to get the Specialist or mission package out of harms way after completing to the objective.
Sharpshooter Poor. Sharpshooters are either too isolated or too busy shooting to serve as an effective squad leader, and don't get access to that many defensive perks.
Grenadier Good. As another class that leans on charge-based core abilities and with some access to defensive perks, Grenadiers benefit nicely from having officer perks, as you don't always want to solve a problem with a precious grenade, especially on longer missions. Cooldown based abilities, such as Focus Fire, are ideal picks here.
Specialist Excellent. Further cementing their identity as toolboxes for any mission, Officer training gives specialists even more options to confront a particular problem, especially tools that don't drain precious charges. Given how little the Specialist's primary weapon is employed, little opportunity cost is paid in use of Officer abilities, so go crazy on those action-costing abilities, such as Get Some, Jammer, and particularly Focus Fire.
Psi Operative Situational. As Psi Operatives will already spend a lot of time "in the tank" training Psionic abilities, further sidelining them for officer training can be a prohibitive opportunity cost. However, its important to note that Psi Operatives ascend their ranks much faster than regular soldier classes, so if you get psionics early, you can quickly get a colonel or field commander trained for some GTS upgrades and strategic benefits. The Officer haven bonus also stacks with the Psi operative haven bonus for detecting faceless, so you can quickly sanitize the globe of faceless spies with these soldiers. On the battlefield, Psi Operatives already have a lot of cooldown-based abilities competing for attention, particularly the ever-valuable Stasis and Mind Merge abilities, so its viable but not excellent.