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 that reached at least Steam Age
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. Can be lowered or increased by the AI Aggressiveness game setting.
- Border friction – Affects how much negative Opinion Border Friction generates.
- Bravery - Affects how willing the empire is to declare rivalry or go to war with someone stronger. List below shows required relative power of the empire with the personality compared to potential targets.
- 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.
These preferences determine how an empire designs its ships. They are ignored if the AI is facing an enemy heavily focused on a certain type of weapon or defense.
- Weapon preference - Preferred weapon type the AI personality will use on its ships.
- Hull ratio - Amount of utility slots used for hull boosters on ships.
- Armor ratio - Amount of utility slots used for armor on ships.
- Shields ratio - Amount of utility slots used for shields on ships.
As an example, an empire with 0.5x Shield ratio and 0.5x Armor ratio will design ships where the Utility slots will contain 50% Shield and 50% Armor components.
When the game is started the personality with the highest weight will be assigned to the AI empire. 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).
Note: Species with the Lithoid or Necroid archetype will use a racial room regardless of personality.
|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.|
||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.|
|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.|
||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.|
|Available only with the Nemesis DLC enabled.|
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 (though it has been known to appear on occasion, especially in older versions of the game). As a fallback personality, Despicable Neutrals has no behavior modifiers, but it does have a rather funny and memorable description: "What makes a species turn neutral ... Lust for gold? Power? Or were they just born with hearts full of neutrality?" This is a quote from the Futurama television series.