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This article has been verified for the current PC version (3.2) of the game.

Wars are not decided only in space. In order to capture enemy planets, entire armies will be needed, along with the preparation and battlefield awareness to properly use them. However planets may only be invaded if the system's starbase has been occupied.

CombatEdit

 
Although secondary to space battles, ground warfare is a vital aspect of many wars.

Ground combat takes place between the planet owner's defense armies and the invader's assault armies. The number of armies that can be engaged in combat on either side is five plus one-fifth of the size of the planet. Armies not engaged in combat will be placed a row behind the fighting armies and replace any killed army.

Generals are leaders who command armies and give them bonuses. However Generals have a 5% chance to die whenever one of their armies is killed.

Each army has a morale value, and once morale drops low enough the army will be negatively affected with the following modifiers:

Morale Penalty
50% −25%   Army damage
0% −75%   Army damage

Armies gain experience from combat and can rank up. Higher rank armies are more effective in combat.

An attacker can always attempt to retreat. However there is a significant chance that each retreating army is destroyed while attempting to return to space, making retreat a risky endeavour and something to do only in very poorly chosen engagements.

Planet devastationEdit

Planet devastation is a measure of how much damage has been caused to the planet's population centers. It goes from 0 to 100% and the higher it is the more damage defensive armies take and the more likely pops are to be killed. Every 1% planetary devastation causes a 1% decrease in   Housing,   Amenities,   Trade Value,   Resources from Jobs,   Upkeep from Jobs,   Growth Speed and   Immigration Pull.

Planet devastation is caused by orbital bombardment and assault armies. Assault armies have a Collateral Damage modifier that determines how fast they cause planetary devastation. Defense armies do not cause any.

  Devastation   Damage to armies   Kills pops   FTL inhibitors functional   Tree of Life alive
0% 50%      
25% 100%      
50% 100%      
75% 200%      

Planet Devastation recovers by 0.05% daily if planet is not being invaded or bombarded.

Defense armiesEdit

Defense armies are automatically recruited by certain buildings from the species working them and can be robotic or organic. They are stationed on planets and used to defend against enemy armies. While they are stronger one-for-one than assault armies and their loss does not cause War Exhaustion, their static nature means that investment is necessary to fend off a concentrated attack. Their combat ability is also improved by certain technologies.

The type of army recruited depends on the pop working the building that spawns them. Defense armies do not incur any upkeep beyond that of the building that creates their Job. Defense armies do not cause Collateral Damage.

Army Type Army Damage Morale Damage Health Morale Pop Species
  Defense Army 2.25 - 4.50 2.25 - 4.50 250 250 Organic
  Robotic Defense Army 1.50 - 3.00 1.50 - 3.00 250 immune Robot
  Drone Grid 1.65 - 3.30 1.65 - 3.30 220 immune Machine Unit
  Sentinels 6.00 - 12.00 30.00 - 60.00 1400 immune Event

Assault armiesEdit

An empire can recruit armies of any species that is present within its borders, as long as there are members of that species living on the planet which the army is recruited from. Unlike Defense Armies, they are based in space and each recruited army will board a transport ship. Transport ships are unarmed but automatically upgraded with the latest defense components.

The amount of armies from a species an empire can have at the same time is limited to the number of pops of that species living within the empire, except for   Clone Army. Armies without species like   Xenomorph Army are unlimited as well.

Army Cost   Time   Upkeep   Damage Morale Damage   Collateral Damage   Health   Morale   War Exhaustion Requirements Species
  Assault Army   100 90 1 1.50 - 3.00 1.50 - 3.00 100% 200 200 100% Biological
  Slave Army   50 60 0.5 1.50 - 3.00 1.12 - 2.25 150% 200 150 50%   Slave Processing Facility Biological (enslaved)
  Clone Army   75 30 0.75 1.50 - 3.00 1.50 - 3.00 125% 200 200 50%   Gene Banks Biological
  Robotic Assault Army   150 90 1.5 1.50 - 3.00 1.50 - 3.00 150% 400 immune 50%   Droids tech
  Robotic Workers Allowed
Robot
  Psionic Army   250 120 2.5 3.00 - 6.00 4.50 - 9.00 50% 350 500 300%   Telepathy Biological (psionic if Utopia is installed)
  Xenomorph Army   200 100 2 3.00 - 6.00 6.00 - 12.00 500% 400 immune 25%   Morphogenetic Field Mastery None
  Gene Warrior Army   300 150 3 3.00 - 6.00 3.00 - 6.00 75% 500 500 300%   Gene Seed Purification Biological
  Undead Army   100 60 0.75 1.50 - 3.00 2.40 - 4.80 125% 200 immune 50%   Necromancer jobs Biological
  Hunter-Killer Army   100 90 1 1.50 - 3.00 1.50 - 3.00 200% 200 immune 50%   Machine Intelligence Robot
  Battle Frame Army   200 120 2 2.25 - 4.50 3.00 - 6.00 200% 500 immune 100%   Machine Intelligence
  Adaptive Combat Algorithms
Robot
  Mega-Warform   800 500 8 6.00 - 12.00 9.00 - 18.00 400% 1200 immune 400%   Machine Intelligence
  Biomechanics
None
  Cybrex Warform   250 500 8 7.50 - 15.00 15.00 - 30.00 500% 1400 immune 400%   Cybrex War Forge relic
Can only be recruited on the capital
None
  Titanic Beast   300 90 1 4.50 - 9.00 9.00 - 18.00 300% 1000 600 200% Titanic Lifeforms event chain
Only 3 can be recruited
None
  Azizian Army   250
  50
90 1 4.50 - 9.00 9.00 - 18.00 100% 1000 400 100% Ice Alien event chain
Only 3 can be recruited
None
  Imperial Legion   300 150 3 3.75 - 7.50 3.75 - 7.50 75% 600 600 300%   Galactic Emperor
  Imperial Legions resolution
Only 12 can be recruited
None
  Psionic Avatar event only none 7.50 - 15.00 15.00 - 30.00 100% 1400 immune 500%   Shroud event None
  Nanite Warform event only none 15.00 - 30.00 90.00 - 180.00 500% 3600 immune 400%   A Quiet Stroll event None

Army rankEdit

As armies fight battles they will increase in rank, improving their stats based on their experience points. Armies get +2 experience points each time they deal damage and +1 when they take damage.

Rank Exp Points Effects
Regular 0 - 100 None
Experienced 100 - 1000   +10% Damage
  +10% Morale
Veteran 1000 - 10000   +20% Damage
  +20% Morale
  +10% Health
Elite ≥ 10000   +40% Damage
  +40% Morale
  +20% Health

Army starting experience can be increased by +100 by each of the following:

Orbital bombardmentEdit

Orbital bombardment occurs when a fleet is in orbit around a hostile planet, and is generally a precursor to invasion. Genocidal empires can even opt to skip the invasion entirely and simply exterminate all life on the surface. Orbital bombardment causes damage to any defensive army but also   Devastation. Effectiveness is based on the Fleet Size of the fleet in orbit, where maximum effectiveness is reached at 200 Fleet Size.

Stance Planet damage Army damage Pop kill chance Other effects Requirements
  Selective 50% 100% 25%
  • Does not kill the last 21 Pops
  • Does not bomb planets with no armies on it
None
  Indiscriminate 100% 150% 50%
  • Does not kill the last 11 Pops
    Pacifist
  Armageddon 150% 200% 100%
  • If the last pop is killed, the planet becomes a   Tomb World

One must be true:

  •   Fanatic Purifiers
  •   Determined Exterminator
  •   Become the Crisis
  Javorian Pox 20% 150% 150%
  • Does not kill   Mechanical Pops
  • If the last pop is killed, the planet becomes a   Tomb World
  Javorian Pox Sample relic activation
    Pacifist
  Raiding 100% 50% 100%
  • Abducts pops instead of killing them
  • Species with Displacement, Neutering or Extermination species rights will still be killed
  • Does not cause Terror Bombing opinion if successfully abducted
  • Does not kill or abduct the last Pop
One must be true:
  •   Barbaric Despoilers
  •   Nihilistic Acquisition

Orbital Bombardment Damage dealt to enemy planets can be increased by the following:

Source Damage
  Overwhelming Force tradition +20%
  Orbital Trash Disperser component +25%
  Munitions Plant juggernaut aura +30%
  Death from above, lvl   crisis stage +20%

Orbital Bombardment Damage taken from enemy fleets can be reduced by the following:

Source Damage
  Planetary Shield Generator building -50%
  Survival of the Fittest tradition -25%
  Never Surrender tradition -25%
  Fortress World designation -10%
  Fortress Station designation -10%
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