Other Abilities (LWR)

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Accuracy Cap

Critical hit chance (otherwise known as 'Crit') is capped at the current hit chance. This means that a soldier with 100 crit and a 1% chance to hit will only have a 1% chance to crit due to a -99 accuracy cap.

Air Strikes

If you are fighting in a country that has some country defense, they may offer the officer on your squad the ability to call in an Air Strike.

The formula to calculate the percent chance a country will offer you an Air Strike is:

20 + Country Defense / 2

If they've made the offer, officers you control you can press 'V' or click the ability to call in an Air Strike. This can only occur once per mission.

Air Strikes will occur at the end of the turn they are called, and will bombard all enemies that are active and visible from above with multiple explosions.

Each enemy has 20 chances to be struck by an explosion. The chance for each explosion to strike is x%, where x is how many opportunities have been calculated. For example, the first chance is 1%, the second is 2%, the last explosion is a 20% chance, and the average is a 10% chance.

Each explosion deals 3-6 damage + 10% of the target's max hp in a 2-tile radius, with damage falloff like other explosives (50% damage at the periphery). The explosions will land within a 6-tile radius of the targeted enemy, using the same mechanics as rocket scatter (6 tiles being the maximum distance, but most explosions will land in a significantly smaller area of around 3 tiles).

Because of these mechanics, air strikes tend to be best against enemies that are clustered together, as each enemy will take damage from multiple enemies worth of explosions. They can also be useful for disrupting psionic abilities.

Base DR

Any unit that has any Base Damage Resistance (represented in multiples of 20 by grey pips on their HP bar or in the F1 panel as a small number next to Total DR) will have it reduced as their armor HP declines. Specifically, the square of % of armor HP lost is equal to the % of base DR removed.

This is not to be confused with red fog which only kicks in when the unit has lost all armor HP.

Base DR stacks additively with itself (e.g an ability that gives 10 base DR and an armor that gives 20 base DR give the soldier 30 base DR total).

Base DR stack multiplicatively with other forms of DR to calculate Total DR. Total DR is represented by a grey shield to the left of their HP bar and in the F1 panel as a large yellow number.

Berserk

If multiple non-blueshirt soldiers on XCOM's team have died, are bleeding out, or are stabilized, all other non-SHIV members that are idle gain the ability to go Berserk. Only 1 member of the squad can berserk each turn. A unit going berserk will prevent other beginning of turn affects from occurring such as enrage, fatigued, and exhausted. Berserk will only trigger if the aliens could see an XCOM unit at the beginning of their last turn.

Chance to Berserk = 0.5% x # of dead x # of enemies in vision

A berserked unit will enter an enraged state, reload if their ammo isn't full, may move towards the nearest enemy, may fire a shot (at +100 aim), and after done, will still be enraged with 2APs ready to go.

Bleed Out

XCOM soldiers and MECs uniquely will sometimes not die when their HP would be reduced below 1. Instead they will become critically wounded and begin to Bleed Out for 2-4 turns (turns can be increased with a respirator implant or the Dual Heart gene mod). At the start of each XCOM turn the timer is reduced, so often a 2 turn bleed out will only give XCOM 1 turn to react.

The chance that a soldier will receive a critical wound and bleed out (instead of just dying) is as follows:

Bleed Out Chance = 10 x [Max_Base_HP - Overkill_Damage]

Max_Base_HP is the natural max HP the character has without any armor or items. The overkill damage is how much damage the soldier received beyond 0. The Bleed Out Chance is clamped between 0% and 90%.

A soldier with the Dual Heart gene mod will always bleed out the first time his health reaches 0 each battle.

While Bleeding Out, a soldier can be stabilized (preventing death) by a unit with a medikit or revived (return to battle with 33% HP and 1 AP) by a medic with both a medikit and the Savior perk. If a soldier's Bleed Out Timer expires, the soldier will die.

The Bleed Out Timer is normally invisible but is visible if the unit bleeding out has a respirator implant.

If the mission ends in a victory, any soldier bleeding out or stabilized will survive.

If the mission is abandoned, only soldiers bleeding out or stabilized in the drop zone will survive.

If the bleeding out soldier has a medikit, another soldier can use it to stabilize or revive them by moving within two tiles and pressing J.

Boosting

In Long War Rebalance, soldiers have the ability to help other soldiers scale heights by boosting adjacent soldiers.

To boost a soldier, hunker two units adjacent to him on both sides. The soldier must be idle, in cover, and have some remaining AP. Once boosted, that soldier will gain the ability to scamper up any adjacent height a short distance. After the scamper the boosted soldier will have 1 AP left to act with (regardless of how much AP the soldier started with).

Combat Readiness

When an XCOM unit ends the turn with an action point remaining and is idle it activates Combat Readiness:

+1.3 mobility, +10 aim, +1 penetration to all attacks, +20% graze chance, and -20% rocket scatter until the end of the unit's next turn

Activating Combat Readiness also reveals units within 4 tiles and will not reveal the activating unit if they are hidden.

Prepared enemy pods (and on Impossible, enemies that start their turn out of line of sight) also receive Combat Readiness.

Note that while Combat Readiness on XCOM wears off at the 'end' of the turn, on Aliens it wears off at the 'beginning' of each of their turns.

Units that lose their Steadied Weapon because they can't see any enemies at the beginning or end of their turn will gain the Combat Readiness bonus.

Combat Readiness can activate automatically on XCOM through the Heat of Battle mechanic, especially when XCOM is engaging many enemies.

Concussive Blast

All explosive damage has the following effects:

1) Clears overwatch 

2) Chance to disorient equal to the percent of their max base HP they lost to the explosion

Corrosion

Acid grenades, acid spit, and certain melee attacks can apply the Corrosion effect:

Disables passive healing, reduces base DR by 50%, strips 2 + 10% of armor HP at start of turn, -20% aim, -20% mobility, and -20% range for AoE attacks; lasts 3 turns

The only way to remove corrosion is through the use of a medikit (biosoldiers only) or an engineer. Certain platings can reduce the length of corrosion to 1 turn (from 3).

Dash

When a unit (alien or XCOM) spends both AP points to move at the same time (a 'yellow' move) this is called dashing and increases movement by 20% (40% with the sprinter perk). Thus, a unit that dashes will be able to cover 2.4x it's mobility in tiles.

As well, when dashing, units will have 30 more defense against reaction fire.

Defuse

This ability is available to all units (including SHIVs). It allows them to defuse bombs. This ability will Hunker soldiers as they defuse the bomb. At the beginning of their next turn they will finish defusing the bomb at the cost of all of their AP.

Disoriented

Non-mechanical units hit by concussion grenades will become Disoriented:

Prevents reaction fire, -15 defense, -30 will, -60 aim, -60% mobility/ability range, -60% melee damage, +60% scatter, lasts through 1 enemy turn

Some grenades and other abilities can also cause Disorientation.

End-in-Idle

An end-in-idle action is any action where the unit that performs the action is Idle after the action. See Idle for more information.

Enrage

If multiple non-blueshirt soldiers on XCOM's team have died, are bleeding out, or are stabilized, all other non-SHIV members gain the ability to Enrage. Berserk will only trigger if the aliens could see an XCOM unit at the beginning of their last turn.

Chance to Enrage = 2% x # of dead x # of enemies in vision

An enraged soldier:

- Deals +100% weapon damage

- Gains +100% mobility

- Gains +100% throw range

- Can reload for 1 AP

- Is immune to triggering non-suppression reaction fire

- Is immune to panic

- Is immune to countercharge

Enraged soldiers can be identified because their AP pips will have turned red.

Elevated Position

Units at a higher altitude then an enemy receive the following benefits:

+5 aim and defense per tile higher (Capped at +30 aim and defense)

Note: Flying units receive the max (+30) defense bonus regardless of their height relative an enemy

Exposed

Exposed units are more vulnerable and shots against them have +50 critical hit chance.

Units not protected by cover are considered Exposed. This also means that any unit that is Exposed will not be receiving any benefits from their cover.

Flanking a target or destroying its cover is an effective method of Exposing a target.

The Hardened perk prevents a unit from being exposed, regardless of cover.

Flying and Non-Hardened units (while technically exposed) do not have increased critical hit chance against them for being exposed. However, perks or abilities that require exposure will still work against flying units.

Fatigued and Exhausted

Soldiers who enter a mission with fatigue may suffer a loss of APs (Action Points) at the beginning of each their turns:

Status	Effect	Chance (Modified by Campaign Length)	Notes
Fatigued	1 AP loss	1% per day of fatigue	Will not occur if Stimmed or Psi Inspired
Exhausted	2 AP loss	0.1% per day of fatigue	Will not occur if Stimmed or Psi Inspired

A NSLW game would decrease the chance per day of fatigue for fatigued/exhausted to trigger to 0.5%/0.05%.

A VLW game would increase the chance per day of fatigue for fatigued/exhausted to trigger to 2%/0.2%.

A ELW game would increase the chance per day of fatigue for fatigued/exhausted to trigger to 4%/0.4%.

Flight

Soldiers with the Archangel or Seraph armors and Hover SHIVs have the Flight ability and a set amount of fuel to power the ability.

Flight consumes 1 fuel per turn while active. Toggling flight on or moving also consumes a fuel.

Units that are flying have their mobility set to 9.3, regardless of what their mobility was on the ground.

Warning: If the pilot is still hovering at 0 fuel they will be forced to land (and may land in a bad location).

Global Abilities

There are a few abilities that do not require line of sight in order to attack enemies, these include: Psychic Storm (Sectoids, Sectoid Commanders, and Ethereals), Mortar Barrage (Mechtoids and Sectopods), Orbital Ray (Drones), and Air Strike (XCOM Commanders).

Aliens will only use a global ability if they have previously seen an XCOM unit, are a Champion unit, or were Prepared on activation.

Grapple

Units with certain light armors have a grappling hook and gain the Grapple ability. Using the Grapple costs 0 AP and can propel the soldier up to 15 tiles. Each armor with the grapple ability has a single use (except for the Ghost Armor which grants 3 uses).

Graze

Any attack that Grazes will deal 50% less damage. This occurs before any damage reduction is taken into consideration (it is a target modifier in the damage calculation process).

Some abilities turn shots into grazes and some any damage into grazes.

Hack

This ability is available to all covert operatives. It allows them to Hack Exalt data relays. This ability will Hunker the covert operative as he/she hacks the relay. At the beginning of their next turn they will finish the hack at the cost of all of their AP.

Once the Hack begins, all Exalt on the map will have their gunlinks scrambled -- they will be unable to use their primary weapon until they install new gunlinks. After the Hack the covert operative will also recover sensitive Exalt information from the relay.

Healing Fatigue

Any active heal (medikit, repair, or restorative mist) decreases the effectiveness of any subsequent active heals by 1. This simulates the inability of the nanobots to keep repairing a unit that is more and more damaged.

Heat of Battle

For every enemy in vision at the end of an XCOM soldier's turn, there is a 10% chance to activate Heat of Battle which automatically grants Combat Readiness.

Hidden

Various abilities can cause a unit to become hidden. They all work slightly differently but all share the similarity in that:

1) They cannot be targeted by the opposition

2) They clear the unit from all enemy overwatch

3) They grant +30% crit

Hunter (Jaeger) = Cloak: reveals at end of turn and on non-movement actions

Stealth (Seeker) = Stealth: reveals on action, lasts up to 3 turns

Concealment (Scout) = Concealed: reveals at beginning of turn, on being flanked, on non-movement actions, and on movement actions that are dashed, not to heavy cover, or in vision of enemies

Ghost Mode (Ghost Armor) = Ghosted: reveals at beginning of turn and on non-movement actions

Shadowed (Shadow Device) = Shadowed: reveals at beginning of turn and on any actions

Sneaking (Sneak Mode) = Sneaking: reveals based on various criteria listed here: Sneak Mode

If an XCOM unit is revealed it will trigger any inactivated alien pods that are in sight.

Holo Targeted

Units that have been hit by a primary weapon (not during reaction fire) with Holo Rounds will become Holo Targeted:

Holo Rounds
Firing at a target during this unit's turn holos [Prevents concealment/stealth, incoming shots gain +20 aim and +1 penetration] them for 3 turns.

Home Ground

Units that are fighting in their home country gain the Home Ground bonus:

+10 aim, +20 will, and +1.3 mobility

Hunker Down

Any biosoldier in cover can Hunker Down:

When protected by cover: +30% cover defense, +30% DR, and immunity to critical hits. Reduces sight radius to 0. Unit cannot be combat ready. Does not trigger reaction fire.

Hunkered units will have their base HP color turn grey.

Idle

Certain abilities vary based on whether or not a unit is idle. Being idle requires the soldier to be doing nothing that could be occupying their attention.

The following abilities cause a unit to NOT be idle:

Being suppressed, suppressing, stunned, maimed, steadying, overwatching, panicking, strangling, being strangled, hunkering, being in One For All, orbital raying, psychic storming, hiding, being critically wounded

Low Hit Chances

In order to properly reflect a reasonable hit chance, while still keeping hit chance calculations as simple as aim minus defense equals hit chance, hit chances below 20% are tapered by half, and those below 10% are tapered again but by 80%. The result is that a shot that would have a 0% chance to hit (based on aim minus defense) would instead have a 10% chance to hit and you would need a calculated hit chance of -100% to reach an actual hit chance of 1%. Chances that have been tapered by half will be colored orange beside the 'to hit' in the F1 info screen. Chances that have been tapered by 80% will be colored red beside the 'to hit' in the F1 info screen.

The actual formula is:

if(iToHit < 20)
  iToHit += 0.5 * (20 - float(iToHit));
if(iToHit < 10)
  iToHit += 0.8 * (10 - float(iToHit)) ;

Note: All final hit chances are still clamped between 1 and 100.

Maim

All sidearms have the Maim ability:

Fire 2 shots at -20 aim that deal 1 damage each where any hits against a biologic target with 1 HP will Maim the target instead of dealing damage

Stun rifles will also Maim targets at or under 4 HP on a failed stun.

Any target that is Maimed will:

Skip the next turn and disable reactive abilities (e.g. Close Combat Specialist, Reactive Targeting Sensors, Overwatch)

Overload

Weapons with the Overload ability upgrade standard shots to break enemy overwatch and have a chance to disorient units equal to the percent of total HP they lost.

Overwatch

Overwatch can only be triggered if the unit has an enemy in sight. Using overwatch will overwatch all units currently in Line of Sight. Overwatching units will fire a reaction shot against any unit that was overwatched and that acts (unless the action is a move of only 1 tile).

Note: The act of going on overwatch triggers a single reaction shot (as opposed to all potential reaction shots).

Being hit by an explosive (Concussive Blast) or certain other abilities will clear a unit's overwatch status.

Taking non-explosive damage has a chance to clear a unit's overwatch status equal to the % of the unit's max HP the damage was. As an example, a unit on overwatch with 20 max HP that took 5 damage has a 25% chance to have their overwatch broken.

Overwatch Indicators

The HUD icons for aliens will reveal who is overwatching you. A target icon appears at the top right of their alien head in the bottom right of the screen.

Aliens will have a red eye icon above their soldier/pawn if they are on overwatch (teal for XCOM).

Allies that are in danger of triggering a reaction shot will have a red target icon just to the right of their HP. If they have a cover shield it will overlap the top right of the cover shield.

Panic

All panicked units have an 50% chance to recover each turn. If they are going to recover, they will receive a popup saying they are Regaining Control; otherwise they will remain panicking. A single panic will last a maximum of 4 turns.

There is a 2% chance that any panicked unit will recover immediately.

Specific abilities can directly cause panic (e.g. Intimidate, Psi Panic), but all Human units can also panic from taking damage or seeing their squad mates take damage. Exalt will panic less than XCOM and have only a 30% chance of triggering a panic roll when one of their panic events trigger.

Exalt Chances to Panic:

• 30% chance if they are hit for more than 30% of their remaining health (20 will test)
• 30% chance if a squad mate in vision dies (20 will test)
• 30% chance if a squad leader in vision dies (40 will test)

XCOM Chances to Panic:

• They are hit for more than 50% of their remaining health (30 will test)
• A squad mate in vision panics (0 will test)

Penetration

Units with penetration will do more damage to units with a form of damage resistance. Specifically, after damage resistance is calculated, for every 1 point of penetration the damage is increased by 1 and the damage resistance is decreased by 1.

Units can gain penetration through various perks, weapons, and equipment. As well, for every 10 damage dealt to a target, an extra penetration is added.

Penetration resistance works in the opposite manner, reducing penetration by 1 for each penetration resistance.

For more information, see the Complete Damage Formula.

Pinpoint Accuracy

Whenever a shot has over 100% hit chance, half of the amount over 100 is added to the critical hit chance and is called Pinpoint Accuracy. It represents a soldier being so accurate that they are more likely to land a critical hit.

Point Blank

If two units are within 1 tile of each other but still protected by cover, they will gain a Point Blank bonus which will bypass many of the benefits of cover (even though they are technically not flanking).

Units at Point Blank will:

Bypass cover defense, bypass cover DR, and gain an crit bonus as if their target was exposed

This acts similar to if they were actually flanked. This does not, however, negate any perks or abilities that work when the target is protected by cover (as the target is still protected by cover).

Reaction Fire

Reaction fire is any shot that occurs when it is not that unit's turn (Eg: Overwatch).

Basic reaction fire has 2 properties different than normal fire:

It bypasses 50% of cover defense and 50% of cover damage resistance

It cannot crit

Reaction fire will trigger when a unit acts (uses any ability or moves >1 tile) and the firing unit has a hit chance of 30 or higher. When the firing unit has a hit chance of less than 30 they will say something along the lines of not being able to target the enemy; aliens will display an exclamation mark (!) above their heads.

Certain actions are quick enough that they won't trigger reaction fire, this includes:

Steady Weapon, Reload, Hunker Down, One For All

Suppression reaction fire will fire regardless of hit chance or action type.

Targets that trigger reaction fire when moving will be treated as uncovered.

Reaction fire can be upgraded with:

Opportunist
Reaction shots gain +10 aim and can critically hit.

Reaction fire will occur before the triggering unit has completed its action or movement. Units that take damage from reaction fire will have less stats when they go to complete their action. For example, using a psionic attack will have a lower hit chance if the unit took damage from a reaction shot and lost will due to red fog. However, hit chance of shots, target locations, and scatter are all calculated before any reaction fire and thus will not be affected by any damage taken before the action (unless, of course, the damage is fatal).

Reaction fire will not occur from or against units that are hidden (concealed, stealthed, shadowed, ghosted, or cloaked).

Reaction fire will not occur from units that are Disoriented.

All reaction fire that damages a target has a chance to Stagger the target.

Units that are Dashing will gain a defense bonus against the reaction fire.

Red Fog

Damage to a unit's base HP causes Red Fog which:

Reduces aim, will, melee damage, throw range, rocket accuracy, and mobility by half the percent of base health lost

The amount of each of the maluses are directly proportional to % base HP lost. Damage to a unit's armor HP has no effect on red fog.

The second wave option Just a Flesh Wound turns red fog off.

Note that base DR is reduced by armor HP loss and is not considered an effect of red fog and thus is not affected by abilities that minimize or circumvent red fog.

Reload

Grants full ammo to the active weapon. Does not trigger reaction fire.

Scamper

Both XCOM and Aliens have the ability to Scamper when they first see each other.

Alien Scamper

When an alien pod is revealed all the aliens in the pod will move to more ideal positions (e.g. moving to cover) and will sometimes activate a Deflection Shield.

When revealed, the alien pod can also be affected by 1 of 3 states: Prepared, Off Guard, and Unprepared. All 3 of these are supposed to emulate XCOM having less time or more time to act before the enemy does based on the state of the enemy when revealed.

Prepared

Aliens enter Overwatch on activation, gain Combat Readiness, and possibly other benefits (e.g. enter sneak mode)

The chance for Prepared depends on the number of activated aliens and the Difficulty:

	Chance for Prepared [chance with active aliens]	Max Overwatchers
Easy	0%	0
Classic	10%	0
Brutal	35% [10% for 1 alien active]	1
Impossible	100% [35% for 1 alien active] [10% for 2 aliens active]	2
Pain	100% for 0-2 aliens active	3

Prepared aliens will overwatch on reveal less if XCOM has less total AP available and will not overwatch at all on the first turn of any mission.

Off Guard

Aliens start with no ammo (or, if they do not use ammo, disorientation)

Aliens in newly activated pods will be caught off guard if they make the total number of active aliens 9 or more (11 for larger missions).

Off Guard is intended to simulate the aliens unexpectedly bumping into XCOM.

Unprepared

Aliens skip their first turn

Aliens in newly activated pods will be unprepared if they make the total number of active aliens 12 or more (14 for larger missions).

Unprepared is supposed to simulate the aliens not only unexpecting to bump into XCOM, but also being not ready for any engagement.

XCOM Scamper

When an XCOM unit has completed their turn (0 AP remaining) and a new alien pod is revealed, that unit will receive the ability to Scamper: they can complete a 1AP move but cannot perform any actions. This can only occur once per unit each turn and only if the XCOM unit is not active (i.e. not overwatching, steadying a weapon, etc.).

Exceptions where XCOM units will not gain Scamper:

• Non-idle units
• Units that just used Run and Gun
• Units that are the last active soldier remaining
• The unit that activated the aliens (if it was done with a non-movement action)

Shaken

Every soldier that dies Shakens the remaining soldiers, lowering their will by 5 for each death witnessed. Psi Inspiration can clear this effect.

Shred

Some weapons can Shred enemies. This means they will take extra damage from all regular sources.

Shredder
Primary weapon shots during this unit's turn apply Shred equal to the dealt as a percent of the target's max HP (which increases subsequent damage the target receives by the amount of Shred) to any unit they damage for the remainder of the battle.

Note that additional shred damage is calculated based off of damage dealt, not damage taken; so if a unit resists any damage through DR it does not affect the amount of shred applied.

Some plasma weapons can shred only specific types of enemies and deals shred equal to 2x damage dealt as a percent of the target's max HP:

• Carapace Shredder (Plasma Rifle): shreds biological enemies with Hardened.

• Ether Shredder (Plasma Reflex Cannon): shreds Sectoids, Sectoid Commanders and Ethereals.

• Mechanical Shredder (Plasma Battle Rifle): shreds robotic enemies only.

• Aerial Shredder (Plasma Carbine): shreds flying-capable aliens.

Some explosives (AP Grenades, Javelin Rockets) have the Explosive Shredder perk which allows them to shred enemies at 2x the damage dealt as a percent of the target's max HP.

If a source would apply multiple levels of shred (e.g. a unit with Shredder and Ether Shredder), only the highest level will apply.

Smoke (In Smoke)

Smoke can be deployed by throwing a smoke grenade. The smoke grenade will fill designated tiles with smoke through 1 enemy turn. Any unit within a tile filled with smoke will receive the In Smoke effect.

Smoke increases defense of units in the smoke by 30 and prevents bonus critical chances against them for being exposed, steadying, suppressing, or overwatching. Smoke reduces the aim of units within the smoke by 10.

Both the aim and defense modifications of smoke apply to psionic abilities by modifying the affected unit's will when a psionic ability is being used. For example, a unit in regular smoke has +30 will for the purposes of defending against psionics and -10 hit chance for the purposes of attacking with psionics. As well, being in smoke prevents being hit by Countercharge.

Smoke also has another important benefit: reaction shots will not trigger against units inside smoke.

In Smoke: -10 aim, +30 defense, prevents extra crit from exposed/steadied/suppressing/overwatching, and does not trigger reaction shots -- aim and defense affects psi as well

There are 2 upgrades to regular smoke:

Combat Drugs
Smoke grenades grant +20 aim and +10 crit. Smoke grenades also passively heal 2 HP at the end of the turn. Only affects units that are breathing the smoke. Does not work in dense smoke.

Dense Smoke
Smoke grenades grant an additional +30 defense (+60 defense total -- defense affects psi as well).

Sneak Mode

Sneak Mode only occurs on Impossible or higher difficulties

When all active aliens cannot see any XCOM and there are 4 or more active aliens, at the beginning of the alien turn, those aliens may enter Sneak Mode.

Sneak Mode is where idle aliens that can use cover have a chance to become hidden (except for mutons, they are too big).

If there are less than 4 active aliens all sneaking aliens will automatically stop sneaking.

All sneaking aliens automatically gain the Combat Readiness buff.

Aliens hidden during Sneak Mode will become revealed again if they:

• Perform a non-movement action
• Start their turn in sight of an XCOM unit
• Have an XCOM unit see them exposed (not protected by cover) within 10 tiles
• Have an XCOM unit see them within 2 tiles
• Take any damage
• Are revealed by a revealing ability/device (e.g. battle scanner)

Aliens hidden during Sneak Mode can also give audio clues relevant to their location. This helps XCOM find them.

Stagger

All reaction fire that damages a target has a chance to Stagger the target equal to the percent of their Max Base HP they lost.

% Chance to Stagger = 100 x Base HP Lost / Max Base HP

Staggered units lose all remaining APs, their shots graze, and they cannot enter overwatch

Does not effect melee-only units (zombies, chryssalids, and muton berserkers).

Steady Weapon

Steadying a weapon grants the following:

Grants double base aim, half of weapon damage in pen, reaction fire immunity, and -50% rocket scatter

Steady is lost if unit acts, moves, is suppressed, is hit, or changes weapons. Steady is converted into Combat Readiness if unit can't see any enemies at the beginning or end of a turn.

Steady is only available if the unit can see an enemy.

Steadying a weapon does not trigger enemy reaction fire.

Stimmed

Units that use a Combat Stim on themselves will receive the Stimmed buff:

+2 regeneration, +2.0 mobility, +20 aim, +15 will, immunity to fatigued/exhausted, +20% DR; lasts through 4 enemy turns

Stun

The stun rifle can be used to attempt to Stun autopsied biologic aliens (except for chryssalids). Stunned aliens can be brought home in stored in Alien Containment facilities for interrogations.

The stun rifle will always hit but the chance to stun will never be 100%. The chance is higher if the target is lower in HP.

Targets at or below 4 HP will be Maimed if the stun fails.

Sublimator

Certain plasma weapons have the Sublimator capability which bypasses all DR from the Hardened perk.

Suppression

Targets that are hit with suppression will receive the Suppression effect:

Cannot use reaction fire, -35 aim, -35% mobility/ability range

At the start of their turn, Suppressed targets become Pinned if they are protected by cover, or take Suppressive Fire damage if they are not protected by cover.

If the target acts while under suppression the suppression will break with another round of Suppressive Fire.

Pinned means the unit will lose 1 AP.

Suppressive Fire

Suppressive Fire damage is equal to 35% of weapon damage.

Note that weapon damage is the base damage of the weapon, and does not include any modifiers.

Even though Suppressive Fire will sometimes occur during the enemy turn, it is not a standard shot and thus it does not qualify as a reaction shot (so it will not stagger).

Units with the Mayhem perk can apply additional Suppressive Fire damage immediately when suppressing.

Mayhem
Suppression has 1 turn less cooldown and deals suppressive fire damage immediately.

Units with the Danger Zone perk will apply Suppressive Fire to an area (at 50% damage) as well as the primary target (at 100% damage). This area damage occurs during mayhem suppressive fire and at the beginning of a unit's turn if they are suppressed and not in cover. The area damage does not apply to the suppressive fire that occurs when a unit breaks a suppression effect by acting.

Danger Zone
Suppression affects (with half suppressive fire damage) targets in a 2.5 tile radius around the primary target.

Tactical Retreat

During most missions, officers you control you can press 'Z' to call Big Sky and ask him to perform a Tactical Retreat. If available, Big Sky will proceed to your location within 1-2 turns. At that time, everyone not within 8 tiles of the extraction beacon will become MIA.

Tactical Retreats are an effective method to withdraw critically wounded units and/or pull out after a mission is successful (e.g. after the bomb is defused).

Tactical Retreats are not available indoors, if a bomb is active, if exalt towers are active, or if a VIP is being rescued. They are also not available on the following missions: DLC missions, newfoundland mission, and base assaults/defenses.