Alien Deployment (Long War)

Battlescape

XCOM will end up conducting a variety of ground operations against alien forces, sometimes for the purposes of countering active alien operations like Terror Attacks and Abductions but equally as often for the purposes of raiding supplies and resources from downed or landed alien UFOs. In addition, the Council typically assigns XCOM with some critical mission each month from a random pool, from rescuing special VIPs to disabling bombs.

XCOM will encounter various alien types in these ground operations; each alien type is typically specialized for a unique role in combat. As Aliens further their research into humanity, their ground forces will gain increased health, damage, aim, and so on, and even access to many of the same kinds of perks XCOM utilizes, as befitting their designated role. Furthermore, as their research progresses the aliens will begin to field advanced alien types, and in greater frequency.

While a particular type may not be too threatening by itself, the various alien types tend to synergize well; for instance, Thin Men are good at pinning XCOM down into a long range war of attrition using their Acid Spit, good aim, & Suppression - this can allow the high mobility Floaters, a flying enemy type, to close in and flank XCOM. That said, aliens coordinate poorly at the tactical level, taking actions in isolation without considering any synergy with other units and without formulating any kind of cohesive tactical plan. Each alien evaluates the current state of the battlefield as its turn comes up, chooses an action based on it's AI routine (which varies from alien to alien depending on their capabilities and tendencies), and then executes it. It does not consider what other allies could do on their turn and attempt to synergize, nor does it consider the capabilities of XCOM & attempt to counter them. In short, aliens have a numerical and technological advantage but they're predictable and can be beaten with superior tactics.

Aliens typically deploy in Pods, or groups of 2-8 aliens which become activated in unison if any individual member spots an XCOM operative. Some select missions may involve "drop ins", or enemies that spawn mid-mission. Drop ins always spawn behind cover and overwatching, and are automatically activated. Drop ins are almost always Thin Men, though other alien types are possible depending on the mission.

Pods

Pods are typically comprised of one Squad Leader (often possessed with noticeably more stats and perks) & several regular troopers whose type is related to the leader and who have a chance to receive various upgrades dependent upon Alien Research. Later in the game, bosses with noticeably larger models and massive HP pools make an appearance in certain missions.

Pod composition is dependent upon the leader, with leaders tending to contain supporting troopers of the same or lesser type. For instance, Mechtoid pods tend to contain several Sectoids, whose Mind Merge ability can empower the Mechtoid with a powerful Psi Shield, while Cyberdisc pods tend to contain Drones which focus on repairing damage dealt to the Cyberdisc; conversely, pods led by Floaters or Sectoids only contain units of the same type as the leader. The quantity of aliens in a pod is dependent upon overall Alien Research as well as the total number of aliens on mission; pods are rolled randomly and random numbers of aliens are added to said pods until all available units have been assigned. Quantity and quality of aliens are not dependent at all on Alien Resources, despite rumors to the contrary.

While members of a given pod do not coordinate amongst themselves any better than disparate aliens from different pods will, there is one significant mechanic which is pod-dependent: retreat mode. If a large portion of aliens of a given pod are destroyed (usually all but 1-3 depending on the original size), the surviving members of the pod will begin to fall back, retreating out of sight of XCOM and toward good cover or other, unactivated pods. The aliens will remain in retreat mode until they enter back into vision of XCOM again, though destroying more units from the pod is sufficient to resume the retreat. Aliens entering into retreat mode will be identified by visual and auditory cues; the camera will pan toward the alien shouting or talking, and one of your soldiers will mention that they're falling back.

Conversely, if XCOM is pushed back by the aliens, they'll call for reinforcements to hunt them down. In general, if active aliens exist on the map, aren't in retreat mode, and none of them has any XCOM operatives in sight range at the end of the aliens turn, they'll call all unactivated pods on the map (aside from the Command Pod, if any) to help them hunt down XCOM. Each unactivated pod will begin moving toward XCOMs current location inexorably, and short of retreating or being wiped out the only escape is to defeat all such enemies.

Pod Size

Pods have a number of aliens that are directly dependent upon current Alien Research:

• Small (AR > 0): 2-4 aliens per pod
• Medium (AR > 120): 3-6 aliens per pod
• Large (AR > 240): 4-8 aliens per pod

While increases in pod sizes do not necessarily lead to more aliens on missions, extra aliens rolled that can't fit into any available pod are discarded (see Overflow and Pruning, below). This has the largest effect during early Trap UFOs or Landed Large UFOs, which typically call for way more aliens than can fit in their Small Pods. To partially compensate, such missions typically get an extra pod or two to work with. Larger pod sizes typically means the same amount of aliens overall, just compacted into less pods - though later Trap UFOs and Landed Larges do have more aliens, as they stop discarding them due to having larger pods to work with.

Pod Types

Pods come in three basic types: Soldier Pods, Terror Pods & Command Pods. Soldier pods pull from a pool of most aliens and comprise the vast majority of pods encountered on all missions; Terror Pods pull from a slightly different pool and show up on Terror missions and some large UFOs. Command Pods only appear in UFOs and have relatively rigid compositions. Lastly, for Covert Operations, Exalt have special mechanics which govern the quantity and size of their pods.

• Soldier Pods: Soldier Pods are the most common type of pod, appearing as the majority pod type in every mission except Terror Sites & Covert Operations.

• Terror Pods: Terror pods are a special type of pod that only appear in Terror Sites, Large UFOs, Trap UFOs, Alien Base Assault, and Retaliation missions. They tend to have a greater probability of being higher-mobility aliens, and are the only pod which contains Chryssalids. EXALT also make an appearance in later months.

• Command Pods: UFOs additionally have a special pod called the Command Pod which contains a fixed number of aliens based on UFO type. Outsiders are the most common type, though Sectoid Commanders replace them on larger UFOs after XCOM assaults its first alien base, and Ethereals start appearing after the Ethereal Device is recovered. Thin Men may also appear in very early months in place of Outsiders on Large UFOs. Be warned: if a Command Pod spots XCOM and activates, it will immediately call for reinforcements, causing all remaining alien forces on the map to start moving towards its current location; this makes an early engagement against the Command Pod an incredibly risky affair.

• EXALT Pods: While EXALT have a chance of appearing in Terror Pods, they appear most often in Covert Operations. A typical Covert Extraction contains one jumbo pod of 3-15 EXALT (with pod sizes growing as the campaign progresses), as well as several smaller pods of 1-3 EXALT. If XCOM activates any pod and fails to kill them immediately, the remaining pods will begin slowly converging on XCOMs location. In contrast, Data Recovery contains several pods of 4-6 EXALT who behave as most pods do. All Covert Operations include drop ins or spawns of lone EXALT operatives who may or may not appear in cover and may or may not overwatch.

Overflow and Pruning

The exact amount of aliens or pods used for some mission types that have randomized pods can differ from what is listed, if there is an excess of either pods or aliens.

This can occur for:

• Alien Base Assaults
• All UFO missions (crashed, landed, trap) of all UFO types

Alien Overflow: If there are more aliens that can fit in pods, based on the current pod sizes, additional aliens are discarded.

For example, if the current pod size is Small, allowing for a maximum of 4 aliens per pod, and the mission calls for up to 30 aliens in up to 6 pods, then the mission will have 4 aliens per pod x 6 pods = 24 aliens, with the remaining 6 aliens discarded.

Pod Pruning: If there is no alien overflow issue, Long War will pick the number of pods to use randomly based on the number of pods, current pod sizes, and number of aliens. In the process, it may remove excess pods. Specifically:

1. Calculate the number of pods necessary to fit both the fewest and largest number of aliens per pod.
2. Pick a random number of pods to use between those two values, with equal chance of each result.
3. Compare this chosen value with the number of pods called for by the mission type, and reduce the chosen value to that maximum if it exceeds it.
4. Conversely, if the amount lies below the mission's ordinary maximum, pods are discarded randomly until the number of pods remaining equals the chosen value.
5. Finally, each pod gets a balanced share of the total alien pool, so that all pods have a difference of at most 1 alien between them.

For example: Let's say 16 aliens are present in 1 terror and 4 soldier pods (5 total) for a given mission, and pod sizes are currently Small (i.e. 2-4 aliens). As a result, there there could be as few as 2 aliens per pod (requiring 8 pods to fit all 16 aliens) or as much as 4 aliens per pod (requiring 4 pods to fit all 16 aliens). The game picks a random number of pods to use between 4 and 8 (i.e. 4, 5, 6, 7, or 8), with equal chance of each result (in this example, 1 in 5 chance of each outcome). Because the original mission allows for only 5 pods, this means a roll of 5, 6, 7 or 8 would cause 5 pods to be used (this would occur 4/5ths of the time). Conversely, a roll of 4 (which would only occur 1/5th of the time) would cause 4 pods to be used, with a random pod (one of the 4 soldier pods or the terror pod) discarded. With 4 pods used, each would have 4 aliens; with 5 pods used, 1 would have 4 aliens and the remainder would have 3.

Pod Composition

Pods are comprised of a "Pod Leader" and a number of "Supporting Aliens". The leader determines the potential composition of the pod; the supporting aliens are usually either weaker variations of the same type of alien as the pod leader, or actual support units whose functions and capacities are designed to synergize with and improve the pod leader.

Pod Leaders

The first alien in a pod is always the pod leader. The pod leader alien type defines the alien type of the Adjutant, Navigator, and Generic support aliens that can appear alongside it. While some Pod Leaders are predetermined based on the type of mission being conducted, the vast majority are rolled randomly.

Pod Leaders receive various stat boosts and bonus perks, over and above regular aliens, based on their level (see the Alien Life Forms article for more details). A pod leaders level can be random, fixed, or "tough".

• Fixed: Uses a specific, predetermined leader level.
• Random: Uses standard Leader Level randomization rules; every 40 Alien Research increases the maximum level by 1, up to a maximum of 7 at 280 AR. At 360 AR and beyond, the chance for higher level leaders is higher, but before that, each is equally likely.
• Tough: Uses the same calculation as per "Random" from above, then adds +3 to the result. The maximum is still 7. See tough leaders for more info.

Support Aliens

The 2nd through 8th aliens in a pod are the supporting aliens. They can roll randomly to be Adjutants or Navigators, but if not they default to being a Generic support (though note that the 2nd alien in a pod is always guaranteed to be a generic support). The only thing these rolls affect is the type of alien (i.e. Sectoid vs. Thin Man), and have no effect on the aliens level or research upgrades; see Alien Life Forms for more information on how Alien Research upgrades their ground forces.

The pod leader defines the kinds of support aliens can appear. Weaker alien types tend to be surrounded by aliens of the same type, while strong alien types tend to be surrounded by weaker aliens. Some alien leader types have more than one Generic support alien type; in those cases, the support alien type is rolled randomly per pod, and all Generic support aliens generated within that pod will be of that type. For example, Thin Men leaders may have either Seekers or fellow Thin Men as generic supports, but not both. Furthermore, at high enough alien research, the support alien types for certain alien leader types change. This includes Sectoids, Floaters, Mutons, Heavy Floaters, Muton Elites, and EXALT Elite Operatives.

Navigator

Each supporting alien appearing in spots 3 through 8 has a 30% chance to be a Navigator. Up to 2 Navigators can appear in a pod, so once two are rolled, no more attempts are made. Navigators are not any more likely to have bonuses or upgrades than Generic supports, but they are sometimes of a different type than the generic support aliens. For example, a Sectoid leader is usually supported by Sectoids, but may also be accompanied by Drones, which are the Navigator. Some alien leader types have more than one Navigator alien type; in those cases, the Navigator alien type is rolled randomly per pod, and both Navigator aliens generated within that pod will be of that type. For instance, in the Sectoid example above, the Navigator alien type for a Sectoid leader pod is either Sectoids or Drones; thus, if one or two Navigators are rolled, they are either Sectoids (making them functionally identical to the other generic support Sectoids) or Drones. Furthermore, at high Alien Research, the available Navigators for certain alien leaders change. This includes Sectoids, Floaters, Mutons, and Heavy Floaters.

Adjutant

Each supporting alien appearing in spots 4 through 8 has a 10% chance to be an Adjutant. This check takes priority over the Navigator check; only if a given alien fails to be an Adjutant does the game check to see if they are instead a Navigator. Only one Adjutant can appear in a pod, so once one is rolled, no more attempts are made. Adjutants are a non-leader alien of the same type as the leader alien. They are not any more likely to have bonuses or upgrades than generic supports, but certain pods that have a strong leader alien and weak support aliens can be buttressed by a second alien of the leaders type. For example, most Mechtoids are accompanied by Sectoids and Drones, but sometimes Mechtoids come in pairs; the stronger one is the Pod Leader, while the weaker one is the Adjutant.

Pod Composition Tables

Soldier and Terror Pods

The following tables display the pod leader chances to appear in Soldier Pods and Terror Pods, as well as their associated Support alien type and Navigator. Reminder that the Adjutant is always the same as the leader alien type. If multiple Navigator and Support Alien types are available for a given leader, one is picked at random and applied to all Support or Navigator aliens in a pod. The dates listed are the latest possible date to apply the table. The true determination is based on the amount of Alien Research. Namely, for every 28 points of Alien Research (which, at minimum, is guaranteed to increase by 1 every day), a counter called iMonth increases by 1.

iMonth = Alien Research / 28

Changes in Generic or Navigator supports due to alien research is indicated in Bold. This includes Mutons (iMonth = 8), Sectoids (11), Floaters (12), Heavy Floaters (13), and Muton Elites (14). Furthermore, keep in mind that for the purposes of Landed UFOs, iMonth is increased by +1.

iMonth = 0 (March 1)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	76%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	24%	-	Drone	Drone	Drone
Chryssalid	-	100%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%

iMonth = 1 (~March 29)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	29%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	9%	-	Drone	Drone	Drone
Chryssalid	-	62%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	37%	25%	Floater	Floater	Floater
Thin Man	35%	13%	Thin Man 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%

iMonth = 2 (~April 26)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	21%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	6%	-	Drone	Drone	Drone
Chryssalid	-	47%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	26%	19%	Floater	Floater	Floater
Thin Man	20%	9%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	17%	25%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	10%	-	Floaters 67% Mutons 33%	Muton	Sectoid 50% Floater 50%

iMonth = 3 (~May 24)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	12%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	6%	-	Drone	Drone	Drone
Chryssalid	-	40%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	26%	17%	Floater	Floater	Floater
Thin Man	19%	8%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	16%	21%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	21%	9%	Floaters 67% Mutons 33%	Muton	Sectoid 50% Floater 50%
Cyberdisc	-	5%	Drone	Cyberdisc	Seeker

iMonth = 4 (~June 21)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	10%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	6%	-	Drone	Drone	Drone
Chryssalid	-	32%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	22%	14%	Floater	Floater	Floater
Thin Man	16%	6%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	15%	17%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	22%	7%	Floaters 67% Mutons 33%	Muton	Sectoid 50% Floater 50%
Cyberdisc	9%	24%	Drone	Cyberdisc	Seeker

iMonth = 5 (~July 19)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	10%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	5%	-	Drone	Drone	Drone
Chryssalid	-	29%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	20%	11%	Floater	Floater	Floater
Thin Man	16%	6%	Thin Man 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	13%	15%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	20%	6%	Floater 67% Muton 33%	Muton	Sectoid 50% Floater 50%
Cyberdisc	8%	21%	Drone	Cyberdisc	Seeker
Berserker	-	3%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Mechtoid	8%	9%	Sectoid	Mechtoid	Drone

iMonth = 6 (~August 16)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	9%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	5%	-	Drone	Drone	Drone
Chryssalid	-	26%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	6%	11%	Floater	Floater	Floater
Thin Man	15%	6%	Thin Man 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	12%	13%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	19%	6%	Floater 67% Muton 33%	Muton	Sectoid 50% Floater 50%
Cyberdisc	8%	19%	Drone	Cyberdisc	Seeker
Berserker	20%	11%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Mechtoid	6%	8%	Sectoid	Mechtoid	Drone

iMonth = 7 (~September 13)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	8%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	3%	-	Drone	Drone	Drone
Chryssalid	-	26%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	6%	5%	Floater	Floater	Floater
Thin Man	13%	5%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	11%	14%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	17%	5%	Floaters 67% Mutons 33%	Muton	Sectoid 50% Floater 50%
Cyberdisc	7%	18%	Drone	Cyberdisc	Seeker
Berserker	17%	10%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Mechtoid	6%	8%	Sectoid	Mechtoid	Drone
Sectoid Commander	6%	5%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	6%	4%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%

iMonth = 8 (~October 11)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	6%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	3%	-	Drone	Drone	Drone
Chryssalid	-	20%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	4%	4%	Floater	Floater	Floater
Thin Man	10%	4%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	9%	11%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	13%	4%	Muton 67% Floater 33%	Muton	Muton 67% Seeker 33%
Cyberdisc	9%	15%	Drone	Cyberdisc	Seeker
Mechtoid	10%	8%	Sectoid	Mechtoid	Drone
Berserker	14%	9%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Sectoid Commander	4%	4%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	4%	2%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%
Heavy Floater	14%	9%	Floater 67% Heavy Floater 33%	Heavy Floater	Floater 50% Chryssalid 50%
EXALT	-	3%	EXALT Operative	EXALT	EXALT
EXALT Elite	-	7%	Elite Operative	EXALT Elite	EXALT Elite

iMonth = 9 (~November 8)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	7%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	2%	-	Drone	Drone	Drone
Chryssalid	-	20%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	5%	5%	Floater	Floater	Floater
Thin Man	9%	4%	Thin Man 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	7%	6%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	12%	4%	Muton 67% Floater 33%	Muton	Muton 67% Seeker 33%
Cyberdisc	9%	15%	Drone	Cyberdisc	Seeker
Mechtoid	11%	8%	Sectoid	Mechtoid	Drone
Berserker	7%	8%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Sectoid Commander	4%	2%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	5%	2%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%
Heavy Floater	14%	8%	Floater 67% Heavy Floater 33%	Heavy Floater	Floater 50% Chryssalid 50%
EXALT	-	4%	EXALT Operative	EXALT	EXALT
EXALT Elite	-	6%	Elite Operative	EXALT Elite	EXALT Elite
Muton Elite	8%	5%	Muton 67% Muton Elite 16.67% Berserker 16.67%	Muton Elite	Muton Elite 40% Heavy Floater 30% Mechtoid 30%

iMonth = 10 (~December 6)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	6%	-	Sectoid	Sectoid	Drone 50% Sectoid 50%
Drone	3%	-	Drone	Drone	Drone
Chryssalid	-	19%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	5%	4%	Floater	Floater	Floater
Thin Man	9%	4%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	7%	6%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	11%	4%	Muton 67% Floater 33%	Muton	Muton 67% Seeker 33%
Cyberdisc	9%	14%	Drone	Cyberdisc	Seeker
Mechtoid	11%	8%	Sectoid	Mechtoid	Drone
Berserker	7%	7%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Sectoid Commander	9%	4%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	5%	3%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%
Heavy Floater	11%	8%	Floater 67% Heavy Floater 33%	Heavy Floater	Floater 50% Chryssalid 50%
EXALT	-	3%	EXALT Operative	EXALT	EXALT
EXALT Elite	-	6%	Elite Operative	EXALT Elite	EXALT Elite
Muton Elite	7%	4%	Muton 67% Muton Elite 16.67% Berserker 16.67%	Muton Elite	Muton Elite 40% Heavy Floater 30% Mechtoid 30%
Sectopod	-	6%	Drone	Sectopod	Seeker

iMonth = 11 (~January 3)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	6%	-	Sectoid 50% Elite Operative 50%	Sectoid	Mechtoid 50% Elite Operative 50%
Drone	3%	-	Drone	Drone	Drone
Chryssalid	-	18%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	5%	4%	Floater	Floater	Floater
Thin Man	9%	4%	Thin Man 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	7%	5%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	11%	4%	Muton 67% Floater 33%	Muton	Muton 67% Seeker 33%
Cyberdisc	9%	14%	Drone	Cyberdisc	Seeker
Mechtoid	11%	7%	Sectoid	Mechtoid	Drone
Berserker	7%	8%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Sectoid Commander	9%	4%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	5%	2%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%
Heavy Floater	11%	8%	Floater 67% Heavy Floater 33%	Heavy Floater	Floater 50% Chryssalid 50%
EXALT	-	3%	EXALT Operative	EXALT	EXALT
EXALT Elite	-	6%	Elite Operative	EXALT Elite	EXALT Elite
Muton Elite	7%	3%	Muton 67% Muton Elite 16.67% Berserker 16.67%	Muton Elite	Muton Elite 40% Heavy Floater 30% Mechtoid 30%
Sectopod	-	6%	Drone	Sectopod	Seeker
Ethereal	-	3%	Muton Elite 67% Heavy Floater 33%	Ethereal	Muton Elite 50% Mechtoid 50%

iMonth = 12 (~January 31)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	6%	-	Sectoid 50% Elite Operative 50%	Sectoid	Mechtoid 50% Elite Operative 50%
Drone	2%	-	Drone	Drone	Drone
Chryssalid	-	18%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	5%	4%	Floater 67% Heavy Floater 33%	Floater	Floater 50% Heavy Floater 50%
Thin Man	8%	3%	Thin Man 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	7%	5%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	10%	4%	Muton 67% Floater 33%	Muton	Muton 67% Seeker 33%
Cyberdisc	8%	13%	Drone	Cyberdisc	Seeker
Mechtoid	11%	8%	Sectoid	Mechtoid	Drone
Berserker	6%	7%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Sectoid Commander	8%	4%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	5%	2%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%
Heavy Floater	9%	7%	Floater 67% Heavy Floater 33%	Heavy Floater	Floater 50% Chryssalid 50%
EXALT	-	3%	EXALT Operative	EXALT	EXALT
EXALT Elite	-	6%	Elite Operative	EXALT Elite	EXALT Elite
Muton Elite	11%	4%	Muton 67% Muton Elite 16.67% Berserker 16.67%	Muton Elite	Muton Elite 40% Heavy Floater 30% Mechtoid 30%
Sectopod	-	8%	Drone	Sectopod	Seeker
Ethereal	4%	3%	Muton Elite 67% Heavy Floater 33%	Ethereal	Muton Elite 50% Mechtoid 50%

iMonth = 13 (~February 28)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	6%	-	Sectoid 50% Elite Operative 50%	Sectoid	Mechtoid 50% Elite Operative 50%
Drone	2%	-	Drone	Drone	Drone
Chryssalid	-	17%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	4%	4%	Floater 67% Heavy Floater 33%	Floater	Floater 50% Heavy Floater 50%
Thin Man	8%	4%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	6%	5%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	10%	3%	Muton 67% Floater 33%	Muton	Muton 67% Seeker 33%
Cyberdisc	8%	13%	Drone	Cyberdisc	Seeker
Mechtoid	10%	7%	Sectoid	Mechtoid	Drone
Berserker	6%	7%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Sectoid Commander	8%	4%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	6%	5%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%
Heavy Floater	9%	7%	Heavy Floater 67% Floater 33%	Heavy Floater	Heavy Floater 50% Chryssalid 50%
EXALT	-	3%	EXALT Operative	EXALT	EXALT
EXALT Elite	-	5%	Elite Operative	EXALT Elite	EXALT Elite
Muton Elite	10%	4%	Muton 67% Muton Elite 16.67% Berserker 16.67%	Muton Elite	Muton Elite 40% Heavy Floater 30% Mechtoid 30%
Sectopod	3%	8%	Drone	Sectopod	Seeker
Ethereal	3%	3%	Muton Elite 67% Heavy Floater 33%	Ethereal	Muton Elite 50% Mechtoid 50%

iMonth = 14+ (~March 28)
Pod Leaders			Supporting Aliens (#2 to #8)
Leader Type	Soldier %	Terror %	Generic	Adjutant (#4 to #8) 10% per alien, Max 1	Navigators (#3 to #8) 30% per alien, Max 2
Sectoid	6%	-	Sectoid 50% Elite Operative 50%	Sectoid	Mechtoid 50% Elite Operative 50%
Drone	2%	-	Drone	Drone	Drone
Chryssalid	-	17%	Chryssalid	Chryssalid	Chryssalid 67% Zombie 33%
Floater	4%	4%	Floater 67% Heavy Floater 33%	Floater	Floater 50% Heavy Floater 50%
Thin Man	8%	4%	Thin Men 67% Seeker 33%	Thin Man	Sectoid 50% Thin Man 50%
Seeker	6%	5%	Seeker	Seeker	Seeker 50% Drone 50%
Muton	10%	3%	Muton 67% Floater 33%	Muton	Muton 67% Seeker 33%
Cyberdisc	8%	13%	Drone	Cyberdisc	Seeker
Mechtoid	10%	7%	Sectoid	Mechtoid	Drone
Berserker	6%	7%	Muton 67% Floater 33%	Berserker	Berserker 50% Floater 50%
Sectoid Commander	8%	4%	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Mechtoid (Variant Pod)	6%	5%	Muton 50% Sectoid 50%	Mechtoid	Sectoid Commander 50% Drone 50%
Heavy Floater	9%	7%	Heavy Floater 67% Floater 33%	Heavy Floater	Heavy Floater 50% Chryssalid 50%
EXALT	-	3%	EXALT Operative	EXALT	EXALT
EXALT Elite	-	5%	Elite Operative	EXALT Elite	EXALT Elite
Muton Elite	10%	4%	Muton Elite 50% Muton 25% Berserker 25%	Muton Elite	Muton Elite 40% Heavy Floater 30% Mechtoid 30%
Sectopod	3%	8%	Drone	Sectopod	Seeker
Ethereal	3%	3%	Muton Elite 67% Heavy Floater 33%	Ethereal	Muton Elite 50% Mechtoid 50%

Command Pods

One command pod appears in every crashed UFO mission. They do not move or patrol.

Before the first Alien Base Assault, all Command pods are led by Outsiders, and most Command pods except for large UFOs are staffed exclusively by Outsiders (Thin Men can appear in some cases if the Command pod for a UFO has 3 or more aliens). Afterwards, Command pods for all UFOs except Scouts and Fighters are led either by Sectoid Commanders or, following the collection of the Ethereal Device, Ethereals.

Command Pods
Command Pod Leaders	Supporting Aliens
	Generic	Adjutant 10% per alien, Max 1	Navigators 30% per alien, Max 2
Outsider	Outsider	Outsider	Outsider 67% Thin Men 33%
Sectoid Commander	Outsider 50% Sectoid 50%	Sectoid Commander	Mechtoid 50% Outsider 50%
Ethereal	Muton Elite 67% Heavy Floater 33%	Ethereal	Muton Elite 50% Mechtoid 50%

EXALT Pods

All pods led by an EXALT leader, whether they are in EXALT missions or mid-to-lategame Terror pods, follow this structure. A given EXALT pod leader usually has a 25% chance to be an Operator, Heavy, Sniper, or Medic, though some leaders are fixed as Operators in certain early game EXALT missions. Note that the generic support type for EXALT Elite Operatives changes when iMonth >= 6 (i.e. Alien Research >= 168).

EXALT Pods
Pod Leaders	Supporting EXALT
	Generic	Adjutant 10% per support, Max 1	Navigators 30% per support, Max 2
EXALT Operator	EXALT Operator	EXALT Operator	50%: EXALT Heavy 50%: EXALT Sniper
EXALT Heavy	EXALT Operator	EXALT Heavy	50%: EXALT Sniper 50%: EXALT Medic
EXALT Sniper	EXALT Operator	EXALT Sniper	50%: EXALT Heavy 50%: EXALT Medic
EXALT Medic	EXALT Operator	EXALT Medic	50%: EXALT Heavy 50%: EXALT Sniper
EXALT Elite Operator	EXALT Operator (AR >= 168: Elite Operator)	EXALT Elite Operator	50%: EXALT Elite Heavy 50%: EXALT Elite Sniper
EXALT Elite Heavy	EXALT Elite Operator	EXALT Elite Heavy	50%: EXALT Elite Sniper 50%: EXALT Elite Medic
EXALT Elite Sniper	EXALT Elite Operator	EXALT Elite Sniper	50%: EXALT Elite Heavy 50%: EXALT Elite Medic
EXALT Elite Medic	EXALT Elite Operator	EXALT Elite Medic	50%: EXALT Elite Heavy 50%: EXALT Elite Sniper

Geoscape

Aliens begin the invasion by taking over a target country to establish a base of operations, choosing a random continent that is not the same as the players starting continent and then choosing a random country in said continent. At some point in March of the first year, the chosen country will inexplicably leave XCOM, seemingly without warning; in reality, the aliens launched a large-scale operation called an Infiltration mission in which they capture and control the local leadership, setting up a Base to project their influence and coordinate operations. To prevent further Infiltration missions, XCOM will have to maintain a constant pressure over the aliens in the coming months, denying the aliens success in their ground and air operations so that they view XCOM as a more important Threat, or denying and starving the aliens of Resources; either is sufficient to prevent aliens from capturing countries instantly, though XCOM will still have to deal with the spread of panic which, if allowed to reach critical levels, provides aliens with a window to capture countries smoothly and easily without the use of the relatively expensive Infiltration mission.

Air Operations

The Aliens conduct various UFO missions in the air to achieve their nefarious ends and support their invasion effort. Missions are planned monthly, at the start of the month, and take into consideration Alien Resources and the Threat Level the aliens perceive XCOM to represent. Damaging, shooting down, destroying and/or raiding UFOs is one of few means of denying & depriving the aliens of resources; ironically, doing so also increases threat, so XCOM always finds itself caught between protecting countries from a surge in alien resources and protecting itself from a surge in perceived threat.

The Aliens primary strategy is to invade and take over the globe; they perform this by capturing countries, tending to focus on those adjacent to their existing holdings first before expanding outward to other continents. This tendency is governed primarily by an RNG that is biased towards focusing efforts on the highest Panic countries, though there is always a possibility of another target being chosen. Bombing runs and Terror missions are used to spread Panic to targeted countries to allow the aliens a window to infiltrate and control the local leadership and then install a base; with enough resources, however, the aliens will attempt Infiltration missions to capture countries directly regardless of panic levels.

The Aliens will attempt to Scout out and then Hunt down satellites to deny XCOM their primary means of engaging UFOs, with the RNG biased towards protecting their own bases from being raided before striking at XCOM-controlled airspace to deny XCOM air superiority. The Aliens' available intelligence on XCOM satellites is abstracted somewhat: they will spend their monthly Hunt missions - representing satellites they've located through other means - to strike at XCOM satellites directly; conversely, they'll spend their monthly Scout missions to try and locate satellites, spawning an additional Hunt mission over and above their monthly supply if the mission is successful. Where they are Scouting or Hunting is completely random, though they will always run the designated missions in countries with a Satellite over them.

If the Aliens consider XCOM a large enough threat, they will begin to focus their efforts on sabotaging XCOM operations directly. Above-average resources and threat is sufficient grounds to get them to send a ground team after your Interceptor Bases, though they'll only start doing so once XCOM has built it's first Firestorm. They'll even initiate an assault on XCOM Headquarters directly, though this requires a few months of maximum threat and resources to get the aliens to take such drastic & costly measures. High threat will also increase the likelihood that the Aliens will attempt to trap XCOM ground forces by sending a larger contingent of aliens to a given landed UFO than normal, though keep in mind that only UFOs that have successfully landed can be traps.

The Aliens also run various missions across the globe to support their invasion efforts: Research missions to give their air and ground forces a statistical edge in combat and Harvest missions to increase their supply of Resources so that they can field more missions and more powerful UFOs. Denying the Aliens the ability to do either helps in the long term, though the need to respond is not as dire as it is for other missions. On top of that, at high enough threat, the Aliens will often try to avoid XCOM-controlled countries when harvesting resources, though being forced to choose less optimal sites reduces the return. Lastly, Aliens will also conduct Abduction missions - for nebulous and mysterious reasons that may tie in with their overall purpose for invasions. Abduction missions don't particularly help the aliens or hurt XCOM, though failing to respond to them will still spread panic.

Alien Bases

As the Aliens expand their coverage over the globe, they install Bases to exert pressure and psionic control over the local governments. Where XCOM fails to present itself as an adequate threat and given a surge in resources, the Aliens will capture target countries directly with a large scale military operation; that said, a country too busy managing it's own panicking citizens due to unchecked alien activity will effectively hand itself over on a silver platter. Regardless of the method, the country will withdraw from the Council, and soon an Alien Base will be constructed on the target country to cement their foothold.

Alien Bases provide aliens with a selection of benefits:

1. They exert control over a target country, preventing it from returning to the XCOM project while the base is intact. Captured countries will no longer provide XCOM funding & will not make requests to the Council; as a consequence, XCOMs means of acquiring additional income & personnel is disrupted. Finally, XCOM will be deprived of any country & continent bonuses associated with the given country, though XCOMs starting country bonus (if the aliens manage to capture XCOMs starting country) will not be removed.
2. They provide the Aliens a monthly supply of Bonus Research, which steadily increases the capabilities of their air and ground forces. More research means more alien types and higher-leveled aliens, as well as more powerful UFOs.
3. They provide the Aliens with a steady supply of Resources, which allows them to run more dangerous air operations more frequently & using more powerful UFOs.

To rob the aliens of these benefits, these bases can be assaulted, though locating them requires progressing far enough through the main research path to research Alien Operations and unlock production of the Skeleton Key (as per vanilla), as well as installing an Satellite over the target country. However, unlike vanilla, multiple bases can be assaulted per playthrough (one for each country that leaves the XCOM project); in fact, doing so returns the country to the fold and allows it to resume its funding and make requests.

Strategic Target

For some UFO sorties, including UFOs conducting Terror attacks, Bombing campaigns, and Infilatration missions the aliens select a "strategic target" from among those countries that are geographically adjacent to existing alien bases, prioritizing those with the highest panic.

The above diagram shows all adjacencies. Every time the aliens select a strategic target, they select the three countries with the most panic from among a list of all countries adjacent to any alien base.

The strategic target selected is:

90% of the time: The country with the most panic

5% of the time: The country with the second-most panic

5% of the time: The country with the third-most panic

This random selection is performed for each individual UFO sortie and is calculated at the beginning of the month when the mission is scheduled.