This article is for the PC version of Stellaris only.
AI empires act and behave based on their AI Personality type which in turn is dictated by factors like what ethics, traits and government type the empire has. The personality type will direct the empires' behavior in terms of foreign- and domestic policy, fleet budgeting, political behavior and general empire characteristics. The empire's personality can be found in the diplomacy screen, just under the ethics list.
AI behavior can be broken down into characteristics and behavior modifiers:
Characteristics determine whether an empire will take certain actions or not:
- Attack neutrals - Attacks neutral entities (Tiyanki, Nomads, Enclaves, Caravaneers and the Infinity Machine)
- Conqueror – Uses the Claim Wargoal during offensive or defensive wars
- Displacer - Uses the Displacement Purge policy against xeno pops and does not accept refugees
- Dominator – Invades pre-FTL civilizations
- Infiltrator – Uses the Covert Infiltration Observation mission when dealing with pre-FTL civilizations
- Isolationist - Always keeps borders closed and does not accept refugees
- Liberator – Uses the Liberation Wargoal during offensive or defensive wars
- Multispecies – Gives all species Full Citizenship rights
- Opportunist – Is likely to attack another empire if that empire is fighting a war
- Propagator - Aggressiveness changes to 10 when it can't expand
- Purger – Purges xeno pops
- Robot exploiter – Uses the Servitude Artificial Intelligence policy
- Robot liberator – Uses the Citizen Rights Artificial Intelligence policy
- Slaver – Enslaves aliens
- Subjugator – Adopts the Domination tradition tree early and uses the Subjugation Wargoal during offensive or defensive wars
- Uplifter – Uplifts pre-sapients and technologically enlightens pre-FTL civilizations
Behavior modifiers indicate the modification of certain common actions happening as compared to a generalized norm (1.0x).
- Aggressiveness – Affects the chance of declaring wars against empires they hold negative Attitude towards.
- Border friction – Affects how much negative Opinion Border Friction generates.
- Bravery – Affects how much Relative Power is considered when declaring Rivalry or War.
- Colony spending – Affects how many resources the empire will spend in setting up new colonies.
- Combat bravery - Affects the chance of retreating from battle. At 1.0 they will attempt to retreat from an engagement after losing 50% of their fleet.
- Military spending – Affects how many resources the empire will spend on its fleets and armies.
- Threat concern – Affects how much negative Opinion Threat generates.
- Trade willingness – At 1.0 willingness the empire will accept a deal that is equally good for both sides. Lower values mean the empire will only accept deals shifted in its favor.
- Weapon preference - Preferred weapon type the empire will use on its ships.
- Hull ratio - Amount of hull boosters the empire will have on its ships.
- Armor ratio - Amount of armor the empire will have on its ships.
- Shields ratio - Amount of shields the empire will have on its ships.
The above ratios determine what percentage Hull/Armor/Shield attachments the empire's ship designs will have. As an example, an empire with 0.5x Shield ratio and 0.5x Armor ratio will use ship designs where the Utility slots will contain Defense components consisting of 50% Shields and 50% Armor.
When the game is started the personality with the highest weight will be assigned to the AI empire. All existing weight modifiers are additive, not multiplicative.
Note: Any behavior modifier listed above that is not included in a given entry in the below table means its value is equal to the norm (1.0x).
|Available only with the Utopia DLC enabled.|
|Available only with the Synthetic Dawn DLC enabled.|
Fallen empires have unique personalities compared to regular AI empires. They always have only one fanatic ethic.
|Sleeping fallen empires|
|Keepers of Knowledge||
||This Fallen Empire dedicates itself to the hoarding of technologies that it believes should be kept out the hands of young and irresponsible races. Pursuing dangerous lines of research may draw their ire.|
||This Fallen Empire dedicates itself to the preservation and defense of its holy sites. Colonizing systems that they consider sacred is likely to incur their ire.|
||This Fallen Empire dedicates itself to the study of the younger races. Purging and enslaving other species may draw their ire.|
||The Fallen Empire dedicates itself to the defense of its borders against any intrusions. Colonizing systems that border them is likely to draw their ire.|
|Awakened fallen empires|
||This Awakened Empire seeks to control the technological level of all other civilizations in the galaxy. They are likely to attack any empire that will not surrender its technological independence.|
||This Awakened Empire seeks to impose its religious doctrines on the galaxy. They are likely to attack any empire that will not willingly convert|
||This Awakened Empire seeks to protect the lesser races from each other. They are likely to attack any empire that does not accept their enforced peace.|
||The Awakened Empire seeks to restore its lost dominion over the galaxy. They are likely to attack any empire that does not acknowledge their overlordship.|
Machine Fallen Empire
|Available only with the Synthetic Dawn DLC enabled.|
||This Fallen Empire is an ancient artificial intelligence that appears to be operating on some sort of caretaker protocol. It behaves erratically but seems to post no direct threat to us.|
||This Awakened Empire is an ancient artificial intelligence acting as a galactic custodian. It will focus all its efforts on defending sapient life against the ongoing crisis.|
||This Awakened Empire is an ancient artificial intelligence that has gone berserk. It is likely to attack anything and anyone around it.|
If the process of assigning an AI personality to an empire fails (usually due to a glitch) and the AI empire in question is left without an assigned personality when the game begins, the game will assign it the Despicable Neutrals personality as a fallback. Otherwise, this personality type should not appear in a normal playthrough.
|Personality||Characteristics||Behavior modifiers||Prerequisites||Weight & Modifiers||Description|
||What makes a species turn neutral ... Lust for gold? Power? Or were they just born with hearts full of neutrality?|