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This article may contain outdated information that is inaccurate for the current version of the game. It was last updated for 1.0.

Slavery boosts a population unit's food and minerals production at the cost of its energy and research production, as well as the Mod pop happiness.png Happiness of both the pop and of onlookers.

Enslavement and emancipation[edit]

With the slavery policy active, the player can enslave and emancipate pops through the planet surface panel. This can not be done on worlds governed in sectors. However the Sector AI has notorious issues with proper enslaving, often enslaving on the wrong tiles or even every pop. As such setting slaves up manually and then disallowing the governor to manage slaves is adviseable.

The slavery options availible depends on the pop to be enslaved, the Empire Ethos and can happen in any of 3 severity levels:

  • Non-Individualist.png Individualist empires can enslave everyone, but it is primarily an option for Collectivist.png Collectivist due to the happiness effects on the Enslaved pops.
  • Xenophobe.png Xenophobe have the option to enslave every species but their main species.
  • Every empire with AI policy set to servitude can enslave Synths Pops. Lower Tier robots can never be enslaved.

The two severity levels are Full and Regulated, with "Reproduction Prohibited" being an optional addition to Full:

  • Full + Reproduction gives the same benefits and drawbacks as normal Full slavery. Additionally if there are no free pop left on a planet, already growning pops of that species are canceled and no new growing pops of that species can spawn on the planet. This incurs an additional -5% Happiness penalty on top of slavery itself.
  • Full gives the Full bonus. However it does incur Diplomatic Penalties and the Docile Slaves faction will push for regulation
  • Regulated gives less bonus, but placates the Docile Slaves faction and reduces the diplomacy penalty making it generally the better longterm option.

An enslaved pop produces +20% Food.png Food and Minerals.png Minerals, but -33% Energy Credits.png Energy and -75% Physics Research.pngSociety Research.pngEngineering Research.png research. This basically means that slave pops should work food and mineral tiles; leaving power plants and research to free pops. It doesn't mean that slaver empires actually suffer reduced energy and research output (since slave pops doesn't and shouldn't work those tiles). Regulated Slavery reduces the bonus by -10% in both areas, but placates the Docile Slaves faction. The Edict "Share the Burden" is there specifically to offset that penalty.

Production of Food and Minerals can be increased in various ways:

  • Leader trait iron fist.png Iron Fist governor increases slave productivity by 15%
  • Slave Processing Facility increases productivity by 15%
  • Tech repeatable improved slave mineral output.png Stimulant Diet is a repeatable technology, wich adds +5% to both mineral and food production of slaves.
  • Decadent.png Decadent trait has an interesting effect - without at least one slave pop on a planet its owners will suffer -10% productivity themselves (general unhappiness penalties will still apply as usual though).

Slavery and Happiness[edit]

As can be expected, people are not exactly happy to be enslaved or even the prospect of being enslaved. Non-Collectivist.png Collectivist pops suffer a happiness penalty from being enslaved. This penalty is worsened massively for a short time after the pop is freed. Individualist.png Individualist pops suffer happiness penalty from being enslaved, from having slavery allowed and from having slaves in the same planet (based on number of slaves). Individualist pops can never be happy with slavery being in use. Unless they are also Collectivist.png Collectivist, Xenophile.png Xenophile and Materialist.png Materialist pops suffer similar happiness penalties when Aliens and T3 Robots are enslaved.

Slaves automatically join one of the slavery related factions, wich can cause issues due to slave uprisings, but also takes them out of normal factions.

Slaves do not get any Happines modifier to Ethic divergence. As poor happiness no longer incurs a penalty by default, this mostly cuts off any Happiness Bonus the slave might aquire.

Enslaved pops do not trigger Xenophobia, making Decadent viable with Xenophobia.

(Un)happiness effects[edit]

The baseline unhappiness of being enslaved is -15% for the slaves, and an empire-wide happiness penalty on free folks. The penalty is calculated from the fraction of slaves on the planet or one-half of the fraction of slaves in the empire, whichever is worse. The maximum penalty would be -100% for full enslavement of a pop's own species and -50% for aliens. Emancipated slaves will bear a grudge (-30% happiness) for five years, but other pops will not.

Baseline values modified by pops' Slavery Tolerance. Collectivist.png Collectivist and Fanatic Collectivist.png Fanatic Collectivist pops have 100% tolerance, and suffer no penalty for being enslaved or seeing slaves. Individualist.png Individualists and Fanatic Individualist.png Fanatic Individualists will be more upset by 50% and 100%. The Alien Slavery Tolerance of Fanatic Xenophobe.pngXenophobe.png Xenophobe ethics works the same way, but only if the enslaved pop is a different species than the xenophobic pop (notice that xenophiles do not have mirroring modifiers here).

Slavery tolerance does stack, which can produce interesting results. For example, fanatic collectivists under Transcendent Empire will have +30% happiness while enslaved and also will make other available collectivists even happier, while freaking out all their less crazy neighboring empires, and an individualist xenophobe under any other government will have baseline unhappiness from alien slaves even despite his xenophobia and general acceptance of xenoslavery policy.

Additional flat happiness penalties:

  • Decadent.png Decadent pops gain -10% if slavery is prohibited, but do not suffer additional happiness penalties because of slavery legality regardless their ethics.
  • Xenophile.png xenophile and Fanatic Collectivist.pngCollectivist.png collectivists suffer -5% if slavery is legally limited to xenos (-10% for Fanatic Xenophile.png)
  • Individualist.png Individualist pops have -5% happiness modifier if slavery is fully legal (-10% for Fanatic Individualist.png).
  • Slaves gain additional -5% if their procreation is prohibited.
  • As mentioned, emancipated slaves will suffer -30% for 5 years.


Understandably, slavery can be reasonably carried out only in a tolerant empire. Since slavery impact is empire-wide, any conquered non-tolerant pops will likely begin with a large happiness malus for seeing others being enslaved, which curiously gets removed once they themselves are enslaved. This can create a situation in which conquered pops can only be managed as slaves. It is wise then to shift to produce Energy Credits.png energy and Physics Research.pngSociety Research.pngEngineering Research.png research with the tolerant free people, since slaves are terrible at those.

Slaves with the fanatic-collective ethic suffer no happiness penalty from being enslaved. Strangely, however, it appears that POPs without fanatic collective on a slave world are usually happier as slaves than they are emancipated, due to severe modifier from "was enslaved" and adjacency to slaves.

Importantly, however, slavery can cause both internal and external strife; if your citizens or neighboring empires are opposed to slavery (for instance because they are individualists or fanatic individualists) then this can cause serious civil and diplomatic issues. Allowing slavery gives a +10 modifier to other slaver nations, but -10 to all nations prohibiting it.

You can enslave any pop, but it is best done on pops that are different from the loyalist starting position. Doing so also moves the POP into a 'Slave' faction, removing any past allegiances they might have had; useful in the face of potential rebel uprisings. Presently, it is not possible for slaves to revolt by themselves.


Game concepts
Governance EmpireGovernment typesPoliciesEdictsLeaderFactionsPopulation
Exploration ExplorationMapSpeciesAnomalyEventsFTLFallen empirePre-FTL speciesSpaceborne aliens
Colonization ColonizationCelestial bodyEconomyBuildingsTechnologyConstructionSpaceportFleet
Diplomacy DiplomacyTradeSubject empireAlliances and federationsAI personalities
Warfare WarfareSpace warfareLand warfareOrbital bombardmentMilitary stationShip designer
Others EthosTraitsTerraformingGenetic modificationSlaveryCrisisPreset empiresEaster eggs