Summary
Artificial intelligence in grand-strategy games can often become the bane of the players or simply just devolve as another resource for them to exploit in order to gain the upper hand while playing. Uniquely,Stellaristries to solve this issue by having multiple AI personalities in the game based on their picked ethics, traits, and government type.
Among those AI personalities, some were quite rare to be encountered inStellarisdue to the mixture of their traits that might require a player to customize or have the exact same combination within its randomly generated empires. Furthermore, some also might be locked behind time as it requires the player to advance at a certain time point of the game or is a personality of one of the fallen empires in the game.

1Migratory Flock
This particular AI personality is relatively peaceful, with a wish to expand, explore, and spread their species throughout the galaxy. When encountered, this civilization will prioritize having a migration treaty to allow their people to move freely into other empires without any extra cost while being friendly to their neighbors.
Although the AI personality is one of the common ones, the occurrence of this particular personality is quite rare due to a civilizationneeding a particular traitto be classified as a Migratory Flock. Therefore, unless the player specializes a custom empire to spawn in-game, a Migratory Flock AI will be quite hard to encounter.

2Ancient Caretaker
A fallen empire dedicated to caring for the species of its long-lost precursors.
This particular AI personality is reserved only for one of the fallen empires, which can have varied personalities themselves. Ancient Caretaker primarily keeps to themselves as a civilization, even though they havenumerous technological advantages in their arsenal.
Once in a while, they might send a request for the player to have them give up one of their population to ‘safeguard’ the player’s species. However, it might inflict negative modifiers on the player’s civilization should the request be accepted.

3Keepers of Knowledge
A fallen empire personality dedicated to gaining technologies across the galaxy.
Similar to the Ancient Caretaker, Keepers of Knowledge mainly keep to themselves and are one of the possible personalities for fallen empires; they focus on hoarding technologies for themselves and might be tempted to help other civilizations should their request be accepted.
Usually, they will request a high-level Leader from the player, typically a Scientist, for their own collection and interest in gaining more technology. However, should a player refuse to do their bidding, their disposition towards the player might decrease, which could lead to a war between a humongous fallen empire against a new player empire.

4Indolent Overlord
Overlord that heavily relies on their vassals (requires Imperial Fiefdom origin).
This personality is quite rare on normal playthroughs due to its specific conditions for spawning for an AI empire. The Indolent Overlord AI personality only spawns when a player has the origin of Imperial Fiefdom, becoming the overlord for the civilization with the exact origin.
Typically, Indolent Overlords didn’t seek to actively expand their empire, preferring to only sit backwhile using their influenceto order their vassals to gather everything else from the galaxy. However, should their vassals decide to gain independence, the overlord might be tempted to use their advantage to keep their vassals in check.

5Splintered Species
AI Personality for pre-FTL sentient civilizations with lots of potential.
This particular AI personality is reserved only for pre-FTL civilizations that are not quite there yet to be space-faring civilizations. From their response to meeting the player, one can gauge what the potential of the civilization would be in the future.
Hostile reactions typically meant that the civilization would have a xenophobic ethic and potentially become a menace to the galaxy as a fanatic purifier. On the other hand, a peaceful reaction could mean for the civilization to be more friendly to the others by being xenophile.

6Despicable Neutrals
Quite a rare AI Personality that only happens in AI empires with less-than-ideal circumstances.
Not many players have seen this particular personality, and rightly so, because this personality only occurs when there is a bug within the game. Normally, this AI personality would only appear when an AI civilization encounters a bug that took away its initial personality and, in turn, makes it personality-less.
Players often have reports of the personality disappearing within the AI civilization when they subjugated a particularly hostile AI civilization, such as a fanatic purifier or determined exterminator. However, it could also occur in normal civilizations as well, due to the unpredictability of the bugs within the game.

7Benevolent Corporation
A specialized AI Personality for the Minamar Specialized Industry (requires Broken Shackles or Payback origin).
Similar toIndolent Overlord, which starts with vassals, this particular AI personality is reserved only for a special AI civilization called Minamar Specialized Industry. Moreover, they are only available whenever a civilization has either Broken Shackles or Payback origin since they have a specialized storyline for them.
Typically, similar to Indolent Overlord, the civilization is not expansionist and prefers to keep to themselves. However, civilizations under their ‘contract’ might break free, which results in an opening for other civilizations near Minamar’s to incite a war and disturb the peace within the area.

8Benevolent Interventionists
AI Personality of an awakened empire bent on keeping the galaxy in peace with any means necessary.
This personality only appears when a certain fallen empire is awakened, specifically the Enigmatic Observers. Unlike other awakened empires that might convert other empires to their side with a negative modifier, Benevolent Interventionists only ask for the playerto join their federationand not attack other empires in it.
Moreover, they will not ask for resources from their signatories and instead just ask them to be peaceful with each other. However, signatories might also get dragged into a galactic war since awakened empires would declare war on each other, culminating in a ‘War in Heaven.’

9Fanatical Befrienders
Rare AI Personality that only wishes to be friends with everyone in the galaxy, including fanatical purifiers.
To balance the monstrosity and hostiles that exist in the galaxy, an AI personality that only wishes to befriend everyone also exists. Fanatical Befrienders can spawn at a very rare rate, except when forced to spawn by players via empire customization and spread their friendliness across the galaxy.
Unfortunately, they are often unable to get out of the early game phase due to their friendly disposition. More often than not, they will be subjugated by their more hostile neighbors around their territory. Should a player manage to befriend and keep one safe, a Fanatical Befriender is guaranteedto be a loyal allyby your side.

10Metalhead
Very rare AI Personality with only one goal in sight: Metals.
If fanatical purifiers are not metal enough, Metalhead will be more to the player’s liking as they are hellbent on making sure everyone’s life is miserable in the galaxy. Their high aggressiveness made sure that they wouldn’t seek peace against their neighbors, even strong ones like Fallen Empires.
To balance their aggressiveness, Metalheads will be quite resourceful in finding necessities for wars, such as focusing on minerals and alloys for their fleets. Being neighbors with one will prove to be a headachefor the new players ofStellaris, but it also poses a significant challenge that will be fun to navigate.