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This article may contain outdated information that is inaccurate for the current version of the game.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 1.5.

Slavery boosts a population unit's usefulness for the empire at the cost of its energy and research production, as well as the Mod pop happiness.png Happiness of the pop. Patch 1.5 adds 3 settings for Enslavement of a Species and several forms of slavery through the species rights system. Slavery can no longer be controlled on a per-pop basis and the sector no longer has control which pop will be enslaved.

Enslavement and emancipation[edit]

With the Slavery policy active, an empire can choose which species can be enslaved as well as how they are enslaved via species rights. Enslavement is done automatically based on the species and (in some types) what they are working on.

There are the following Enslavement options:

Option Description Note
No Slavery Full Citizenship and Residency. All pops of this species are free, but not necessarily able to produce leaders. This is the default for every species that cannot be enslaved.
Caste System Pops are only enslaved if slavery would not give them a production penalty for any resource on their tile. In particular buildings that produce Unity and Mineral tiles under Domestic Servitude are not included, due to the penalties. This type is only available for Authoritarian.png Authoritarian empires.
Full Slavery Every pop of this species is enslaved. Production of the tile is not considered. Instead the slaves use is dictated by the slavery. This is a requirement for a certain set of slavery types. It is only available for Xenophobe.png Xenophobe empires and cannot be applied to the empire's founding species.

Slavery types are as follows:

Type Pop Effects Notes Description
Chattel Slavery Minerals.png +10% Minerals
Food.png +10% Food
Energy Credits.png -33% Energy Credits
Research.png -75% Research Output
Unity.png -75% Unity Output
Mod pop happiness.png -20% Happiness
Chattel Slaves have their rights curtailed to maximize productivity, and commonly work with Food.png Food and Minerals.png Mineral production. Chattel Slavery is the most common form of slavery in the galaxy. Whether for life or a limited time, unrestricted access to the labor of others is in some parts seen as a privilege with numerous counter-duties attached, and elsewhere considered a self-evident prerequisite for a functioning society.
Domestic Servitude Minerals.png -25% Minerals
Energy Credits.png -25% Energy Credits
Research.png -50% Research Output
Unity.png -50% Unity Output
Mod pop happiness.png -10% Happiness
Domestic Servants increase the Happiness of free Pops but are less productive than other slaves or even free Pops.
  • +10% Mod pop happiness.png Happiness to free Pops on the planet (this bonus cannot stack).
  • Requires the Utopia.png Utopia DLC.
Domestic servants spend much of their time tending to the needs of free Pops - some are assigned to individual domiciles, while others tend to public spaces. The split in their duties reduces their "hard" resource output, but the quality of life gains for free Pops frequently outweigh this drawback.
Battle Thralls Mod army damage mult.png +20% Army Damage
Energy Credits.png -15% Energy Credits
Research.png -50% Research Output
Unity.png -50% Unity Output
Mod pop happiness.png -10% Happiness
Battle Thralls have a lesser penalty to Energy Credits.png Energy and Research.png Research production and make excellent soldiers for local Armies.
  • Requires the Slaves citizenship policy.
  • Requires the Utopia.png Utopia DLC.
Battle thralls are weaponized serfs, often trained from birth in the martial arts and conditioned for absolute obedience. While prized as soldiers, the battle thralls fare poorly in fields where they cannot utilize their sheer physical strength and resilience.
Livestock Food.png +3 Pop Food Output
Mod pop happiness.png -30% Happiness
Livestock Pops can not be employed to produce resources, but are instead regularly culled to increase the Food.png Food supply.
  • Requires the Slaves citizenship policy.
  • Requires the Utopia.png Utopia DLC.
Livestock is Pops!

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

  • Leader trait iron fist.png Iron Fist governor trait increases slave productivity by +10%
  • Building slave processing.png Slave Processing Facility building increases productivity by +10%
  • Civic slaver guilds.png Slaver Guilds Civic increases slave productivity by +10%
  • Tech artificial moral codes.png Share the Burden edict increases productivity by +10%
  • Tech repeatable improved slave mineral output.png Stimulant Diet is a repeatable technology, which adds +5% to both Minerals and Food production of slaves
  • Enslaved pops (regardless of type) do not receive happiness related bonuses or penalties to production.

Slavery strategy[edit]

  • All types of slavery will heavily penalise science research and Unity generation, and species being fully enslaved should not use either of those building types for best efficiency.
  • Caste System is highly selective. It allows using all the bonuses from the slavery where it can help, without any of the penalties. This setting will maximize the Slavery types output, without causing the same level of Unrest and while also completely ignoring any penalties. It is the default setting for Authoritarian empires. However, in some situations getting at least one pop enslaved for bonuses and similar effects can be tricky.
  • Chattel Slavery works best with slaves in Mines or Farms but is nearly useless for science, and the least effective for energy credit production.
  • Domestic Servitude provides a happiness bonus to free pops while also making the slave less unhappy, but is less useful for production than the other slavery types. It can be used to offset the penalty for a repugnant Xeno Slave or boost production across the planet.
  • Battle Thralls are obviously the best option for creating armies, but it also has the least penalty for generating energy credits, while leaving mineral production at the default level.
  • Livestock are completely useless except to generate 3 food per pop per month. This yield is independent of what the tile would normally produce, so no building or tile yield has to taken into account. It is unclear if planetary or empirewide bonuses apply. One should not waste Minerals or Energy on building anything on a Lifestock tile. It should also probably only be used as a stopgap to increase earlygame growth or getting over shortages.
  • Setting a slave race to Limited Military Service will allow building of armies with that species.
  • Any planet with slaves should have a full complement of defensive armies to ensure that unrest is contained.


  • The direct bonus is the increased production from the pops themselves or from free pops on the same planet.
  • It also boosts Authoritarian or Xenophobe Ethics attraction for free pops on the same planet.
  • Slaves can not join Factions and use the baseline Happiness of 50% regardless of Ethics (see below).
  • Slaves operate on an Impoverished Conditions Living Standard. Under Caste System this will override the Living Standards selected for the species as a whole.
  • As a combination of increased income and poor living standards, slaver empires tend to have a lot more Minerals available - but this can vary based on the Slavery type used for the species.
  • Using Caste System, a player can move pops with ethics they wish to suppress to tiles where they become slaves, thus preventing them from strengthening an unhappy faction. The slave unrest does then have to be counteracted though. So this isn't a perfect fix.


  • Slaves are unhappy. -20% for Chattel Slavery and -10% for Domestic Servitude. This is in addition to the penalty from their Living Standards (usually -20% as well).
  • As a result of poor Happiness, slaves will produce considerable Unrest. Also unrest events associated with slavery can be triggered on much lower levels of uncompensated Unrest. Considerable Armies and other Unrest suppression will be needed to counteract this.
  • Slaves are drawn towards Egalitarian ethics. As they cannot join factions, this ties more into the Dangers section below.
  • As slaves cannot join Factions, a large number of pops will not be eligible for forming of factions. This will delay the forming of happy factions and the associated Influence income considerably.
  • Slaves and especially Xeno Slaves have a higher impact on the Unity cost to unlock Traditions.
  • Extremely Egalitarian empires will have issues with the use of slavery.


  • A Unrest-incited slave rebellion is always a danger. The rebel slave empire will try to join an Egalitarian empire after conquest of the planet.
  • The "Stop Atrocity" wargoal has two effects: First it will cripple the Mineral (and possibly Food) income of the empire. Secondly all the former slaves will emancipate as Xenophobes or Egalitarians and are extremely likely join factions almost instantly. This could actually result in even worse Unrest than the slaves themselves.


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