Warfare

Version

This article has been verified for the current PC version (4.0) of the game.

War

As long as there is at least one empire present that is not Fanatic Pacifist, war is an almost inevitable aspect in any game and can be anything from a small border skirmish to a massive interstellar war of conquest. Wars are how mid-game and end-game borders are usually drawn.

When an AI empire is about to declare war, it will first move fleets towards the border of the target. Targeted empires that have any military intel on the aggressor will receive a warning, with higher military intel levels providing a more accurate estimate on when war will be declared.

Depending on diplomatic agreements, wars may have more than one empire on either side. In that case the empire that declared war and the empire that was declared war upon will be designated as the war leaders for their respective sides. Only war leaders can offer or accept surrenders or status quos. AI allies in a war will occasionally send their fleets to follow the fleets of the war leader.

Casus belli and wargoals[edit | edit source]

In order for an empire to start a war, it needs a Casus Belli – a reason to declare war. Each casus belli grants access to at least one type of wargoal, which represents the purpose of the war. Once a war is declared, the attacked empire has a year to choose its wargoals.

Status quo effects do not include the defender's capital. In case of status quo the defender will retain its capital system regardless of occupation.

Casus belli and wargoals	Requirements	Surrender acceptance	Victory effect	Status quo effect
Claim Conquer	Has existing claims on the target's systems	−10 per system −100 per colonized system	Gain ownership of all systems with claims from the loser, even if not occupied. All systems occupied by the loser are returned, regardless of claims. Generate 25% less threat from conquering.	Each side keeps all systems they have fully occupied if they have claims on them. Generate 25% less threat from conquering.
Counterattack Counterattack	The Enemy of My Enemy resolution (3) Target is not a member of the Galactic Community Target is at offensive war with a Galactic Community member	0	Gain ownership of all systems with claims from the loser, even if not occupied. All systems occupied by the loser are returned, regardless of claims. Generate 33% less threat from conquering.	Each side keeps all systems they have fully occupied if they have claims on them. Generate 33% less threat from conquering.
Animosity Humiliate	Either: Rivalry Castigation Proclamation resolution (4) Defender	−25	Gain 100 Influence. Loser loses all of its Influence, gains −33% monthly influence gain and −10% happiness for 10 years. If the loser had the Supremacist Diplomatic Stance policy, it is changed to Belligerent.	Each side keeps all systems they have fully occupied if they have claims on them.
Ideology Impose Ideology	War philosophy policy set to Liberation Wars Target is not a Gestalt Consciousness	−100	Loser and all its individualist subjects are forced to shift ethics towards those of the victor and their rulers are replaced. Loser will leave a federation if it's part of one and any rivalry with the attacker is ended. Authority is also shifted to that of the winner unless the winner has Corporate authority, in which case the loser will gain the Oligarchic authority and the Merchant Guilds civic. If the loser has the Shared Burdens, Crusader Spirit or Divine Sovereign civics it loses them.	If at least 1 colonized system is fully occupied, then all systems fully occupied by the attacker will be turned into an empire with the attacker's ethics and the Liberated origin.
Despoliation Plunder	Barbaric Despoilers civic	−25	Take 250 Energy and 250 Minerals from the loser for every planet they control, regardless of how much they actually have. Loser gets −20% Energy and Minerals for 10 years. During the war, if the attacking empire invades and captures the capital of the defending empire, there is a 50% chance to steal one of the defenders owned Relics.	Each side keeps all systems they have fully occupied if they have claims on them.
Pirate Raid Plunder	Letters of Marque civic	−25	Take 500 Energy and 50 Minerals from the loser for every planet they control, regardless of how much they actually have. Loser gets −20% Energy and Minerals for 10 years.	Each side keeps all systems they have fully occupied if they have claims on them.
Expropriation Expel Corporation	Commercial Pact with the target empire Members of the same Federation Corporate empire has at least one branch office on an owned planet	−50	Corporate empire closes all branch offices on the attacker's planets. Gain 1000 Energy per branch office.	Corporate empire closes all branch offices on the attacker's planets. Corporate empire gains 1000 Energy per branch office.
Hostile Takeover Seize Assets	Both empires have Corporate authority Target has at least one branch office Criminal Heritage civic	−75	All branch offices on planets whose owners have a commercial pact or federation with victor are transferred to the victor. If loser is part of a federation, branch offices on other members' planets are kept.	None
Claim the Galatron Take Galatron	Target empire used the Galatron relic War philosophy policy set to Unrestricted Wars Gestalt Consciousness	−40	Gain the Galatron relic and 100 influence. Loser loses all of its Influence and gains −33% monthly influence gain and −10% happiness for 10 years.	Attacker gains 1000 energy.
Galatron Access Denied Seize Galatron	Target empire used the Galatron relic Target empire has closed borders Driven Assimilator civic Genocidal	−40	Gain the Galatron relic and 100 influence. Loser loses all of its Influence and gains −33% monthly influence gain and −10% happiness for 10 years.	Attacker gains 1000 energy.
Trial of Advancement Council Seat	Target is a member of the Imperial Council By Trial of Advancement resolution	−100	Replace the loser in the Imperial Council.	None
Punishment Humiliate Stop Atrocities Outlaw AI Cleanse Holy Worlds Decontaminate Border Territories	Only available to fallen empires Either the fallen empire's demand was refused or they were rivaled	0	The refused demands are enforced. If the losing empire is not a Gestalt Consciousness, its ruler will also be killed by the winning fallen empire, unless they are the Ancient Caretakers. Loser loses all of its Influence, gains −33% monthly influence gain and −10% happiness for 10 years. If the loser had the Supremacist Diplomatic Stance policy, it is changed to Belligerent. If the loser had the Cosmogenesis ascension perk it also gains −50% research speed for 10 years.	None

Subjugation wargoals[edit | edit source]

Subjugation wargoals seek to end the independence of the targeted empire and subordinate them to the attacker as a subject. If the targeted empire has any subjects of its own, the effects will apply to them as well, and if the loser is part of a Federation, it will leave it. Subjugation wargoals cannot be used against a fallen empire, the Custodian or the Galactic Emperor or if all owned systems of the targeted empire are already claimed by the attacker. All of these wargoals have a surrender acceptance of −100.

In case of a status quo, if at least 1 colonized system is fully occupied then all systems fully occupied will be turned into a new empire with the Liberated origin and the victory conditions will be imposed upon it. The colony with the most pops becomes the new empire's capital.

Casus belli and wargoals	Requirements	Victory subjugation
Subjugation Vassalize Make Tributary Make Subsidiary	Superior relative power to the target empire. Driven Assimilator Devouring Swarm Fanatic Purifiers and not same species Determined Exterminator and not machine species	Subject (initial terms of agreement and Loyalty depend on the Subjugation War Terms policy)
Hegemon Establish Hegemony	President of a level 3+ Hegemony federation Target is not in federation	Hegemony member
Scion Bring Into Fold	Scion origin	Scion of the same overlord
Imposed Inclusion Bring Into Fold	Galactic Nemesis ascension perk Genocidal	Subject (initial terms of agreement and Loyalty depend on the Subjugation War Terms policy)
Imperial Crusade Force Into Imperium	Imperial Crusade resolution	Galactic Imperium member

Paired wargoals[edit | edit source]

The following wargoals are paired together. If an empire starts a war with either of the paired wargoals, the defender will automatically use the other wargoal and cannot pick another one.

Casus belli and wargoal 1	Casus belli and wargoal 2	Requirements	Victory effect	Status quo effect	Notes
Subject Independence	Subject Assert Overlordship	Subject and overlord Subject not in a federation with overlord	If the subject wins, it becomes independent and the former overlord loses all claims on the former subject's systems.	The subject becomes independent and the former overlord gains claims on the former subject's systems.
Secession Leave Hegemony	Secession Assert Hegemony	President refused member to leave federation Federation is at war	If the attacker wins, it leaves the federation and the president loses all claims on the former member's systems. If the president wins, both empires gain a temporary −20 opinion towards each other.	The attacker leaves the federation and the president gains claims on the former member's systems.	All empires that have the same casus belli and are part of the same federation can be invited as attackers.
Allegiance War Secret Fealty	Allegiance War Maintain Servitude	Secret Fealty from one of target's subjects	If the attackers win, all empires that pledged Secret Fealty to the main attacker will become the attacker's subjects and gain +2.5 Monthly Loyalty for 10 years. If the defender wins, the attacking subjects will gain +5 Monthly Loyalty for 5 years and cannot pledge Secret Fealty during that time.	The subject cannot pledge Secret Fealty for 5 years.	All empires which swore secret fealty to the attacker will join the attacker's side.
Imperium Restore Community	Imperium Crush the Rebellion	Imperium: Spark Rebellion operation	Losers gain −60% Diplomatic Weight for 6 years. If the attackers win, the Galactic Imperium becomes the Galactic Community again. If the defenders win, the Galactic Imperium gains +100 Imperial Authority.	All attackers leave the Galactic Imperium and form a federation.
Imperial Rebuke Imperial Rebuke	Animosity Humiliate	Rivalry Galactic Emperor	Gain 100 Influence. Loser loses all of its Influence, gains −33% monthly influence gain and −10% happiness for 10 years. If the loser had the Supremacist Diplomatic Stance policy, it is changed to Belligerent. If the defenders win, the Galactic Imperium loses −25 Imperial Authority.	None

Total War[edit | edit source]

Certain paired wargoals have as their objective the complete destruction of the opposing empire and will cause a Total War. In Total Wars all occupied systems automatically change ownership. Their new owner will be the participant with the highest claim count on it or the nearest war participant (usually the one that conquered the system) if none of them claim the system. In case of a status quo each side keeps all currently conquered systems.

During a Total War surrender is not possible - both empires will have a −1000 Surrender acceptance and the war continues until either one side is fully conquered or a status quo peace is declared. If an empire conquers every owned colony of another empire, the conquered empire is immediately destroyed, ending the war through Debellation. If the destroyed empire had starbases in uncolonized systems that were not conquered, they are removed, making the territory neutral again. All empires in the galaxy will receive an event notifying them of the defeated empire's demise.

Casus belli and wargoal 1	Casus belli and wargoal 2	Requirements	Notes
Containment End Threat	Subjugation Domination	Awakened Empire
	Purification Cleansing	Fanatic Purifiers or Determined Exterminator
	Hunger Absorption	Devouring Swarm or Behemoth Fury crisis level 5
	Sublimation Assimilation	Driven Assimilator
	Existential Expulsion Wipe Them Out	Existential Campaigns technology or Galactic Nemesis ascension perk	Starbases are instantly destroyed instead of being captured in battles.
Colossus Total War	Stop Colossus Stop Colossus	Either empire has a Colossus	War will not end if the colossus is destroyed
Renegade Containment Preemptive War	Self-Defense End Threat	Mutual Defense resolution 5 One empire is not a member of the Galactic Community
Payback End Threat	Payback Impounding Assets	Payback origin Unlocked by event chain
Crisis War Crisis War	Crisis War Crisis War	Declare Crisis resolution	Can be ended by the Repeal Crisis resolution
Event War in Heaven	Event War in Heaven	Awakened Empire	Used by both Awakened Empires against one another during the War in Heaven.
Event Machine Uprising	Event Machine Uprising	Creator empire and AI rebellion	Victor gains 2000-6000 Unity and 200-600 Influence
Event Worst Contact	Event Worst Contact	Fear of the Dark first contact choice

Claims[edit | edit source]

While casus belli and wargoals represent the purpose of a war, claims represent territorial ambitions — the systems which will be controlled by the victor. Which systems can be claimed depends on an empire's War Philosophy policy, with the Unrestricted Warfare philosophy allowing for the claiming of any system not owned by a fellow Federation member. It is possible to claim the same system multiple times to gain a stronger claim on it, up to 10 times, which can outbid the competing claims of allies when going to war together. If multiple empires have the same number of claims on a system, the oldest claim is considered the strongest and if both claims are equally old, then the winning claim will be decided according to the claiming empires' tag IDs (the player empire has tag ID 00 and thus has first priority if involved). In general, claims are expensive in the early game and become less so later on to allow for more decisive wars to be fought. Claims cannot be rescinded while at war but can be strengthened.

Claims have a base cost of 50 influence, modified by the following:

+25 per hyperlane distance from owned territory
+25 if the system has an upgraded Starbase (i.e. not just an Outpost)
+25 if the system is colonized
All costs are increased by +100% during an offensive war
All costs are reduced by −20% if the claimed system belongs to a Rival

If the modifier reaches a total of −100%, then claims will cost 0 influence.

Defenders can freely claim systems owned by their attackers in a defensive war regardless of their War Philosophy policy. Any system lost by any side during a conquest war or total war will give the former owner 10 claims on it.

Winning war with any non-conquest wargoals will always enforce all claims made by the victorious empires before any other effects, regardless of whether these systems were occupied. For example, an empire winning a war with the subjugation wargoal will annex all claimed systems from the loser before making a Vassal of the loser's remaining systems.

Federation warfare[edit | edit source]

The Federation is the more serious counterpart of the Defensive Pact and the inviting attackers mechanic, and serves as a way of ensuring that all participating empires will fight together on the same side in a given war. While a federation does offer a unique amount of defensive cooperation, builds trust and allows military cooperation between member states' fleets and the federation fleet, establishing a conquest strategy can be made more difficult because of the need for consent of the members to declare war, and each member's expectation of a fair share of spoils from each war (which, if not met, will result in an opinion penalty). Depending on the federation's laws, declaring war can require a unanimous vote, a majority vote or just the president's decision. Federation war declarations are dependent only on the president's War Philosophy, which makes this one of the only ways that a Fanatic Pacifist empire can be part of a war of aggression (the other way being through subject terms of agreement).

The empire that wishes to declare war can ask the other federation members for their war goals by using the "Suggest Demands" button. However, AI empires will be very hesitant to declare war on empires that are much stronger than them or have very powerful allies. In that case, the "Suggest Demands" button will not give any results. One exception to this are wars of liberation or to a lesser extent subjugation: usually AI will agree to a liberation or subjugation war even if all the war goals are assigned to the player. The resulting splinter empire could then be made a subject and later integrated by the player.

In case a federation member is attacked, all allies automatically join the war as defenders without need for a further declaration of war. In this case, the member being attacked has a free hand in choosing federation war goals, which could be all in its own favor.

Ending wars[edit | edit source]

Wars can end in two ways: With the surrender of either side or with a negotiated Status Quo peace.

Surrender means that the victor's wargoal is enforced; any claims the winning side has on the losing side are automatically ceded regardless of occupation status and the defeated empire is forced to keep borders open towards the attacker for 10 years. All wars except those of independence have a negative surrender acceptance, which are countered by factors such as relative navy strength (up to +50), war exhaustion (up to +100) and occupation percentage (up to +100). If an empire and all of its allies (if any) has lost control of all of its systems and/or colonized planets during the war, then a surrender will occur automatically.

Status Quo means that the war has reached a point where neither side is able to score a decisive victory against the other or all wargoals have been achieved decisively before any major battles took place, and both sides agree to cease hostilities and settle for whatever gains or losses they have acquired/suffered. Under a Status Quo peace, all fully occupied systems claimed by a belligerent empire are ceded to the belligerent with the strongest claim. In the case of a tie, whoever has the oldest claim on the system is considered the stronger claimant. In addition both sides must keep their borders open towards each other for 10 years. Since surrender is not possible in a Total War, they can end only in Status Quo or the destruction of one empire. Status Quo can be enforced by either side as soon as 24 months have passed since the opposing side reached 100% war exhaustion, and if both sides reach 100% war exhaustion, then Status Quo is enforced automatically after 24 months.

War exhaustion[edit | edit source]

War Exhaustion goes from 0% to 100%, and measures the total weariness and attrition suffered by all empires on one side in a war. War exhaustion goes up from suffering losses during space and ground warfare, destruction of planets (either from Colossus weapons or Armageddon Bombardment), and a passive accumulation over time called Attrition. When a side's war exhaustion hits 100% they can be forced into a Status Quo peace after 24 months. The speed at which war exhaustion accumulates is influenced by factors such as ethics, traditions, technology and the amount of claims being pressed - an empire that is fighting to hold onto a handful of border systems will tire faster in a costly conflict than one whose very independence is being threatened. War exhaustion also means that an empire that is losing a war can still fight to minimize their territorial losses by inflicting high war exhaustion on the enemy.

War exhaustion gain can be lowered by the following factors: If these modifiers add up to −100%, then no War exhaustion will ever be accumulated.

War exhaustion gain0
Source	Effect
Relentless Aggression crisis perk ( Level 2)	−75%
Never Surrender tradition	−25%
Gestalt Consciousness ethic	−20%
Nationalistic Zeal civic	−20%
Supremacist diplomatic stance	−20%
Demobilization Initiative resolution (5)	−20%
Last Resort Doctrine resolution (4)	−15%
Independent Tribunals resolution (3)	−10%
Belligerent diplomatic stance	−10%
Interstellar Campaigns technology	−10%
Galactic Campaigns technology	−10%
Media Conglomerate civic	−5%
Display of Power agenda	−5%
Impenetrable Border agenda	−5%
Military Buildup agenda	−5%
Reverence for Life resolution (2)	−5%

War names[edit | edit source]

Wars will always be named after the attacker and the defender, followed by one of the following names depending on the wargoal:

Name	Wargoal	Other requirements
War	Any	Offensive war against a Fallen Empire
Federation War Galactic War Great War War of the Alliances	Any	War between two Federations
Annexation Attempt Territorial Invasion War of Aggression War of Conquest	Conquer
War of Beliefs War of Ideologies War of Philosophies	Impose Ideology
Border War Confrontation War of Humiliation War of Rivalry	Humiliate	Regular empire
Punitive Expedition	Humiliate	Fallen Empire
Anti-AI Police Action	Outlaw AI	Holy Guardians Fallen Empire
Buffer Zone Creation	Decontaminate Border Territories	Militant Isolationists Fallen Empire
Holy Purge	Cleanse Holy Worlds	Holy Guardians Fallen Empire
Moral Intervention	Stop Atrocities	Enigmatic Observers Fallen Empire or Benevolent Interventionists Awakened Empire
Freedom Struggle Independence War Secessionist War War of Independence War of Liberation	Independence	Attacker is either: A subject A member of a Hegemony Federation A Secret Fealty recipient
Servitude Campaign War of Obedience War of Overlordship War of Subjugation	Vassalize
Tributary War	Make Tributary
Enforced Sponsorship	Make Subsidiary
The War In Heaven	War in Heaven
Holy World War	Make Dominion	Target destroyed a Holy World
Intervention War Preemptive Action Preventative War Self Protection War	End Threat
War of Cleansing Xeno Filth Removal Xeno Purification	Cleansing	Fanatic Purifiers civic
Extermination Campaign Organic Disinfection Program Organic Euthanization War	Cleansing	Determined Exterminator civic
Absorption War Biomass Accumulation Great Gorging	Absorption	Devouring Swarm civic
Machine Uprising	Machine Uprising
Subsidiary Acquisition	Make Subsidiary
Hostile Takeover	Hostile Takeover
Embargo War Expulsion War War of Expropriation	Expel Corporation
War for the Galatron	Take Galatron
Crisis War	Crisis War