Aliens
This page describes mechanics of Alien faction in game. For story spoilers, see Aliens/Lore

The Aliens, or Hydra as they're sometimes referred after the first autopsy, are a non-playable faction. They have their own set of missions separate from human factions.
Aliens usually start on a Kuiper Belt asteroid (such as Haumea, Makemake, Orcus, or Quaoar) with a tier 3 Base and a tier 3 Habitat. They have 1 councilor on Earth and 5 more on Gunships that will soon crash land on Earth. They also start with a Destroyer that will arrive in early 2024. Aliens will expand from the edge towards the core of the solar system but will generally avoid attacking human fleets or habs until they are provoked.
Alien ships bringing councilors to Earth will create an UFO Crashdown Site visible to everyone. Other alien phenomena are created by alien councilor missions and have the be surveyed. Investigating an alien phenomena site will increase Xenology research by 1%.
Alien Agents
Alien councilors always have 25 loyalty, high security, respectable espionage and a set of unique missions. While powerful, these alien agents are usually unable to board a plane, forcing them to travel on foot, only moving between adjacent provinces. As the game progresses, regions that are owned or subverted by pro-alien groups may open up their airports, allowing alien councilors to fly between these regions.
Alien councilors are dangerous, and are notoriously difficult to deal with. Killing and detaining them is required to unlock certain research options, and to prevent the devastating outcomes of their activity.
Alien Threat Level

This panel represents our intelligence section's best estimate about the degree to which the aliens regard our faction as a threat. It is based on our monitoring of pro-alien groups and visible alien activity in the Solar System.
We believe hostile actions against the aliens or their proxies on Earth, and/or a large visible space presence, increases their concern about us, and we may expect the aliens to attack our interests on Earth and in space should the alert monitor reach the maximum level. We also suspect they may launch one-off retaliations in response to direct action by our operatives against them, but they may also lose interest if we avoid opposing them or their proxies on Earth directly for a time.
Our analysts emphasize this is an imperfect estimate. We will correct our estimates when the aliens take direct action against us or by speaking with one of them directly.
The estimate will turn entirely red if we conclude the aliens are in a total war footing against our interests.
~ Terra Invicta Codex, 0.4.85.
Alien Threat meter becomes visible in the Intel panel once the Alien Operations council engineering project has been completed. Alien threat is scored from 0 upwards, with every 10 points increasing the threat level by 1. Alien Threat Level caps at 5, at which point the aliens will start attacking a faction's habs and fleets. The points can go above 50, making it harder to lower it. Gaining threat via hostile actions will worsen relations with The Servants and The Protectorate as well.
See Diplomacy for more details on how threat is gained, reduced, and estimated.
Alien Xenoforming
Scattered and garbled reports of unusual plantlife have now given way to confirmed sightings of vegetation never before seen on Earth. Strange growths have erupted from the affected land, connected by a pulsing lattice of tendril-like roots. Although this unknown flora appears superficially plant-like, its connected nature is more analogous to fungal growth. Furthermore, small movements have been detected among and around these growths, suggesting that whatever has been done to the local environment has enabled other, as yet undocumented, forms of alien life to survive here on Earth.
While these changes remain localized for now, the ultimate purpose of this "xenoforming" is as yet unclear. Do our visitors similarly require it for their own survival, it is to gain some strategic foothold, are they growing something else within the affected environments — or do they seek to transform our entire world into a simulacrum of theirs?
~ Detect Xenoforming Milestone, Terra Invicta, 0.4.86.
Effects
Alien Xenoforming provides several beneficial effects for the Aliens, and also some beneficial effects for humanity:
| Category | Conditions | Effect |
|---|---|---|
| Megafauna Spawning | >100 levels of xenoflora growth | Spawn a Megafauna army and lose 50 growth levels. |
| Megafauna Healing | >75 levels of xenoflora growth | Allow Megafauna to heal in region. |
| Alien Army Healing | >75 levels of xenoflora growth | Additional 0.5% HP regen per day for alien armies in the region. |
| Councilor Missions |
Abductions
|
Gain attack modifier bonus of region xenoflora growth level / 20 × Difficulty. |
|
Enthrall Elites
|
Gain attack modifier bonus of average xenoflora growth level in nation / 20 × Difficulty. | |
| Mission Detection | Alien Councilor | Reduce noise by region xenoflora growth level / 5 |
| Climate Change | Every Month | Remove 0.002875ppm CO2 × average xenoflora growth level. |
| Unrest Rest Value | Alien Nation | Reduce by average xenoflora growth level in nation / 20 |
| Region Secession |
To Adjacent Alien Nation
|
Increase chance by region xenoflora growth level / 10000 |
| Annual Population Growth | None | Reduce by region xenoflora growth level × 0.005%. |
| Enable Random Event | >0.25 levels of xenoflora growth | Alien Friend enabled. |
| >25 levels of xenoflora growth | Hunters enabled. | |
| >25 levels of xenoflora growth | Terror from the Depths enabled. | |
| >25 levels of xenoflora growth | Indigo Dreams enabled. | |
| >25 levels of xenoflora growth | Pretenders enabled. | |
| Visible to owning faction | Unfriendly Locals enabled. |
Increase
Alien Xenoforming is increased by the following:
| Source | Can Create New | Can Add to Existing | Conditions | Added Xenoflora Growth Levels |
|---|---|---|---|---|
| UFO Crashdown | Yes | Yes | None | 0.001 |
| Xenoform Councilor Mission | Yes | Yes | Critical Success | 11 to 20 |
| Normal Success | 1 to 10 | |||
| Sudden Flowering event | Yes | Yes | >0 Abductions | 23.75 to 78.75 Depends on choice. |
| Hunters event | No | Yes | >25 Xenoflora Growth Levels, Pick the Pro-Alien option. |
23.75 to 26.25 |
| Mysterious Obelisk event | Yes | Yes | >1 Abductions, Pick Observe Obelisk option, 20% Chance |
47.5 to 52.5 |
| Pretenders event | No | Yes | >25 Xenoflora Growth Levels, <7 Cohesion, Pick Leave Alone option |
23.75 to 26.25 |
| Unfriendly Locals event | No | Yes | Xenoflora visible to owning faction, Region in Australia, Pick Xenofauna Harmony option |
100 |
| Daily Xenoflora Spread | Yes | No |
>50 to 80 Xenoflora growth levels
|
0 to 1 |
| Daily Xenoflora Growth | No | Yes | None | Xenoflora Growth Levels (Up to a cap.) |
The amount of xenoflora growth levels needed for xenoflora to spread is scaled by region size and type. Specifically, it needs X levels, where X is calculated as follows:
- Set X = (region area in km2) ^ 0.7 / 250, but capped between 50 and 70.
- Round X down to the nearest integer.
- Add 10 to X if the Region is Rugged.
The passive Daily Xenoflora Growth in a region is capped at X levels, where X is calculated as follows:
- Set X to a random value between 0.025 and 0.065.
- Divide X by 2 if the Region is Rugged.
- Divide X by 2 if the Region has Latitude above 50 or below -50.
- Multiply X by 2 if the Region has an Alien Facility.
- Multiply X by the amount of atmospheric CH4 in ppm, then divide by 1.5.
- Multiply X by the amount of atmospheric CO2 in ppm, then divide by 400.
Reduction
Alien Xenoforming can be reduced in the following ways:
| Attacker | Mission | Bonuses | Conditions | Removed Xenoflora Growth Levels |
|---|---|---|---|---|
| Nuke | None | No Space Defense Facility | All Xenoflora Growth Levels | |
| Region Damage | None | None | Xenoflora Growth Levels × Damage Strength | |
| Space Fleet | Bombard | None |
Green Lasers,
|
Depends on weapon. |
| Army | Assault Alien Asset | None | Normal Success | Xenoflora Growth Levels × Army Militech / 10 |
| Critical Success | Also Halve Xenoflora Growth Levels. | |||
| Councilor | Assault Alien Asset | None | Normal Success | (20 to 40) / (Turns per Month) |
| Remove 1 Abduction | Critical Success | (40 to 80) / (Turns per Month) | ||
| Unfriendly Locals Event | Various Event Bonuses/Penalties | Xenoflora visible to owning faction, Region in Australia, Did not pick Xenofauna Harmony option |
100 | |
| Alien Friend Event | Various Event Bonuses/Penalties | >0.25 Xenoflora Growth Levels, Picked Terminate Friend option |
23.75 to 26.25 | |
| Pretenders Event | Various Event Bonuses/Penalties | Picked Humanity First unique option | 23.75 to 26.25 | |
| Indigo Dreams Event | ||||
| Haunted Forest Event | ||||
| Terror from the Depths Event | Various Event Bonuses/Penalties | >25 Xenoflora Growth Levels, Region can access oceans, Picked Naval Warfare option (Needs a navy) |
23.75 to 26.25 | |
| Hunters Event | Various Event Bonuses/Penalties | >25 Xenoflora Growth Levels, Picked Anti-Alien option |
23.75 to 26.25 | |
The Xenoflora Defoliants, Xenological Culls, and Invasive Species Containment projects each multiply the damage done by Armies and Councilors against Xenoflora by 125%, compounding. So researching all three will almost double the amount of xenoflora growth levels reduced by army and councilor assault alien asset missions.
Notably, with all 3 projects, an army only needs 5.12 militech to clear out a entire region full of xenoflora with every assault.
Megafauna
Where previously the land altered by the alien visitors was almost eerily still, now mountainous and monstrous silhouettes move through the unearthly vegetation. There were, until now, still those who refuted the presence of extraterrestrial beings on our world, but the startling footage of these immense new entities is something to demolish the convictions of even the most staunch unbeliever.
Their titanic bulk blots out the light; the land trembles at their step. Trees and buildings are pushed aside as if they were tissue paper, or are uprooted by vast tendrils as if they were mere seedlings, and, even miles away, the very air seems to bend at their deafening cry. All the world knows it now: giants are among us.
~ Alien Megafauna Spawns Milestone, Terra Invicta, 0.4.86.
A Megafauna is an army that can only fight other armies and cause damage to regions. It cannot occupy regions, or oppress unrest. Nor can it be attached to a navy, or cost a nation Investment Points to upkeep.
The Miltech level of a Megafauna army is 2 + the total number of abductions on earth / 100, but capped at 6. So it only takes 400 total abductions (slightly more than 1 per region) to reach the miltech cap of 6.
- When in battle with other armies, a megafauna is not that different from any normal army.
- When in battle with a region, a megafauna simply does its miltech × its health % / 2000 damage to the region every day.
- Outside of battle, megafaunas can only heal in the Alien Nation or in regions with >75 Xenoflora Growth Levels.
In practice, megafaunas deal fairly negligible amounts of damage. Their inability to heal properly means they quickly exhaust their health and die before causing too much destruction.
That can change significantly after the Alien Nation is created, which gives megafaunas a safe harbor to recover in, and rampant xenoflora growth can lead to giant hordes of hundreds of megafaunas.
The following projects help to handle the megafauna threat:
- The Megafauna Necropsy and War Dog Necropsy projects each multiply damage done to megafaunas by 125%, compounding.
- The Urban Armoring project reduces the damage done by Megafaunas to your regions by 50%.
- The Xenofauna Harmony project, which is only available to The Servants and The Protectorate, completely eliminates all damage done by Megafaunas to your regions, and encourages them to move to other regions.
Alien Surveillance
Earth Surveillance Fleets
Survey human behavior from a close Earth orbit. Grants the equivalent of one abduction in every Earth region.
~ Earth Surveillance Fleet Operation Description, Terra Invicta, 0.4.86.
Conditions
An alien fleet can perform an Earth Surveillance operation under the following conditions:
| Category | Requirement |
|---|---|
| Location | The fleet must be in an Earth Interface Orbit |
| Not Busy | The fleet cannot be in combat or in transfer. |
| Ship Module | The fleet must contain at least one ship with a functional Alien Surveillance Module. |
The operation will take 192 days to complete. During this time, any combat would force the operation to abort. Progress is not saved, so the fleet would have to restart the operation from the beginning.
Effects
For each region on Earth, there is a (region population / 10 million) chance that the aliens will gain X Abductions in the region, where X is the number of ships in the alien fleet that have a functional Alien Surveillance Module.
Every ship in the alien fleet then exhausts their Alien Surveillance Module, which means they need to return to an alien space dock to restore its functionality.
Earth Surveillance Habs
As the Campaign progresses, the aliens will attempt to found a Surveillance Platform, Orbital, and Ring hab within the Earth-Luna planetary system. These habs serve the same role as their earth surveillance fleets.
Earliest Creation
The aliens are not allowed to found these Surveillance Habs until a certain number of years have passed. The exact number of years depends on the campaign settings:
| Hab | Cinematic | Normal | Veteran | Brutal |
|---|---|---|---|---|
| Surveillance Platform | 13 | 9 | 3 | 1 |
| Surveillance Orbital | 15 | 11 | 5 | 2 |
| Surveillance Ring | 17 | 13 | 7 | 3 |
These numbers are also divided by the Alien Progression Speed. This is a slider you can adjust in Custom Campaign settings. It is 100% on Long Campaign mode and 200% on Accelerated Campaign mode.
Effects
Every month, for each region on Earth, there is an X% chance that the aliens will gain 1 Abduction in the region, where X is twice the sum of alien surveillance hab module tiers. If the region is part of the Alien Nation, then X is set to 100 instead.
Alien surveillance habs have static designs, so X is easy to compute:
- The Alien Surveillance Platform has exactly one Alien Observation Post, so it adds 2 to X.
- The Alien Surveillance Orbital has exactly two Alien Surveillance Arrays, so it adds 8 to X.
- The Alien Surveillance Ring has exactly two Alien Watchtowers, so it adds 12 to X.
So if the aliens have built all three, then each region has a 22% chance each month to gain 1 Abduction. Unless it is part of the Alien Nation, in which case the region has a 100% chance each month to gain 1 Abduction.
Alien Assault Carrier
An alien transport has set down in the ■■■■■ region in ■■■■■. Reconnaissance imagery shows it disgorging what appear to be troops and war machines. We believe we only have 30 days to stop it.
Any attempt to assault the landing using armies will surely be regarded as a declaration of war upon the aliens and their interests on Earth.
~ UFO Landing UI Notification, Terra Invicta, 0.4.86.
An Alien Assault Carrier is a slow transport ship that carries 3 Invader Armies to Earth. This is usually the first serious threat that a player has to face:
- Shooting down the Assault Carrier generates 30.72 to 46.08 alien hatred, lighting the spark for a long and grueling war in space.
- Yet that is usually preferable to letting it land, because the aliens gain significant benefits from landing assault carriers on earth.
Earliest Creation
The aliens are not allowed to build Assault Carriers until a certain number of years have passed. The exact number of years depends on the campaign settings:
| Difficulty | Cinematic | Normal | Veteran | Brutal |
|---|---|---|---|---|
| Years since Campaign Began | 16 | 12 | 6 | 0 |
These numbers are also divided by the Alien Progression Speed. This is a slider you can adjust in Custom Campaign settings. It is 100% on Long Campaign mode and 200% on Accelerated Campaign mode.
Effects
The aliens appear to have moved to the next stage of their plan for Earth. This is no midnight visitation or surreptitious abduction: This is an open declaration that they are here, and they are powerful. We believe they are preparing to deploy an army of alien war machines -- our visitors having dispensed with all attempts at subterfuge, and arriving on Earth en masse, in plain sight and conspicuously well-armed. Whether this show of force is intended to be a deterrent or is but the vanguard of a full-scale invasion may well depend upon humanity's response to it.
~ Aliens Land Army Milestone, Terra Invicta, 0.4.86.
As soon as the first Assault Carrier touches the Earth, the Aliens Land Army milestone is completed for all human factions. Simultaneously, the ManyAliensOnEarth flag is permanently set to true. This flag is used for many purposes, but its primary role is serving as one of two conditions needed for the alien faction to recruit their councilors directly on earth. Consequently, any attempts to remove all alien councilors from Earth are henceforth significantly more difficult.
30 days later, the Alien Assault Carrier disappears, its parts salvaged and re-purposed to create 3 Invader Armies that start at 50% health but will quickly recover to full if not immediately engaged in combat.
Invader Armies
An Invader Army mainly differs from normal armies in the following ways:
- It does not cost any Investment Points to upkeep.
- Its miltech level is not attached to any nation. Instead, it is 6.75 + the total number of abductions on earth / 5000, but capped at 9. So it takes 11250 total abductions to reach the miltech cap of 9.
- It takes far less splash damage from nukes. Though the nuke will still automatically kill the strongest army in the region.
- Whenever it increases its occupation of an enemy region, it also conducts 1 Abduction.
A nation that is being invaded by Invader Armies may find its Abductions increasing once per day per Invader Army. So even if the Invader Armies eventually fail to conquer the nation, the sheer number of Abductions generated may open the doors for the Alien Councilors to enthrall the nation's elites, handing it over to The Servants.
Alien Facility
The aliens are moving forward with whatever their plans are for Earth and are establishing fixed, defended installations in what they must consider their territory.
~ Alien Infrastructure Milestone, Terra Invicta, 0.4.86.
Effects
An Alien Facility provides several beneficial effects for the Aliens:
| Category | Effect |
|---|---|
| Mission Detection | -6 Mission noise for alien councilors in the region. |
| Flight | Allow alien councilors to fly to and from the region. |
| Xenoflora | 2x cap on daily xenoflora growth in the region. |
| Alien Army Healing | Additional 1% HP regen per day for alien armies in the region. |
| The Alien Nation | Allows The Servants to give the nation to the aliens via the Assume Control councilor mission. |
Creation
An Alien Facility is built wherever and whenever the Build Facility councilor mission is performed. All alien councilors can perform this mission. The Servants unlock a special org that grants them this mission after researching The Alien Nation project.
The following conditions need to be true for the Build Facility councilor mission to be used:
| Category | Requirement |
|---|---|
| Cost | 500 Money must be paid by councilor's Faction. |
| Reach | The councilor must be able to travel to the target region. |
| Unique | The region cannot already have an alien facility. |
| Nation Control | The Servants or Aliens must own every control point in the nation. |
| Abductions | The region must have at least 15 Abductions. |
| Occupation | The region cannot be occupied or being occupied by war enemies. |
Destruction
An Alien Facility can be destroyed in the following ways:
| Attacker | Mission | Bonuses | Conditions |
|---|---|---|---|
| Space Fleet | Bombard | None |
Green Lasers,
|
| Army or Councilor | Assault Alien Asset | Remove 20% of abductions in region (rounded down to nearest integer). | None |
| Gain 2.25 to 3.75 exotics. | None | ||
| Complete Access Alien Tech Milestone. | None | ||
| Complete Access Salamander Corpus Milestone | An Assault Carrier has landed | ||
| Complete Access Hydra Corpus Milestone | An Assault Carrier has landed | ||
| Faction can see Alien Councilors | |||
| 50% Chance OR Mission Critical Success | |||
| Complete Access Live Salamander Milestone | An Assault Carrier has landed | ||
| Mission Critical Success | |||
| Complete Access Live Hydra Milestone | An Assault Carrier has landed | ||
| Faction can detain Alien Councilors | |||
| Mission Critical Success | |||
| 50% Chance |
Alien Administration

The aliens have carved a nation out of the former territory of ■■■■■. Through human politicians there, the new alien nation is presenting itself to the world as a unifying force capable of solving Earth's problems.
With the aliens as the power behind the throne, the nation appears invulnerable to usual attempts to assume political control - crackdowns, purges and coups simply will not succeed. Only an internal rebellion or an outright invasion has a chance to remove the aliens from power.
~ Alien Nation Founded UI Notification (war variant), Terra Invicta, 0.4.86.
The Alien Administration is a nation that is created either when an #Invader Army occupies a region or when The Servants transfer territory to the aliens. The control points of the Alien Nation are always under the alien faction's control, and ordinary coups cannot succeed. The only ways to remove regions from the Alien Nation are:
- Secession
- Raising unrest and wrecking cohesion in the Alien Nation can cause non-capital regions of the Alien Nation to randomly break off to form their own nations or to join existing human nations that have claims on them.
- Revolution
- Once every 4 days, the game checks whether Unrest in the Alien Nation is >9.9.
- If so, a revolution occurs. But in contrast to revolutions in human nations, revolutions in the Alien Nation do not change who owns the control points.
- Instead, regions within the Alien Nation may randomly break off to form their own nations or to join existing human nations that have claims on them.
- And then the aliens will gain 80 hatred, split up among the factions responsible for raising unrest in the Alien Nation.
- War
- Wars involving the Alien Nation differ from normal wars in that regions are never occupied.
- Instead, every time an alien nation's region is occupied, it breaks off to form its own nation or to join an existing human nation that has claims on it.
- If the capital of the alien nation is occupied, then all regions within the Alien Nation may randomly break off to form their own nations or to join existing human nations that have claims on them.
- And then the aliens will gain 80 hatred, split up among the factions responsible for conquering the Alien Nation.
| Terra Invicta mechanics | |
|---|---|
| Factions | |
| Council | |
| Earth | |
| Space | |
| Aliens | |
| Modding & Settings | |


