- Overlord redirects here. For the game expansion, see Overlord (DLC).

Vassalization request towards a Machine Intelligence empire
A subject is an empire that has limited autonomy and is subservient to another, usually strong empire, called the overlord. Their fleets tend to follow their overlord's. In the default galaxy map mode, subjects have the same color as their overlord.
An empire can become a subject willingly via diplomacy; the acceptance depends on a number of factors, particularly relative power. Additionally, having an overall superior or overwhelming relative power enables an empire to use the
Subjugation casus belli to forcefully make another empire a subject.
Subjects, except Satrapies, receive a −50% penalty to their
diplomatic weight. In addition, operation difficulty is reduced between subjects and their overlord.
Loyalty[]
Subjects have a secondary opinion type towards their overlord called Loyalty that ranges from −100 to 100. Subjects with negative loyalty have the Disloyal attitude, which prevents any diplomatic agreements; subjects with positive loyalty have the Loyal attitude, which increases acceptance of diplomatic agreements. Loyalty can also be used as part of trade deals between the overlord and the subject. Sectors released as subjects start with 50 loyalty.
Loyalty is gained or lost monthly based on subject's opinion and terms of agreements; ethics compatibility, relative power, and overlord holdings have a lesser impact as well. A
Pledge of Loyalty can also be negotiated via trade, adding
+1.5 monthly loyalty for the duration of the trade deal; if the subject's
opinion of the overlord is at least 150, the Pledge of Loyalty adds
+2.5 monthly loyalty instead.
If an overlord has multiple subjects, each subject gains −1 monthly loyalty for every other subject. This penalty can be delayed by the
Feudal Society civic,
Franchising civic, or the
Shared Destiny ascension perk.
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Available only with the Overlord DLC enabled. |
Loyalty also grants experience to specialized subjects. In addition, the Suzerains and Sovereignty resolutions -
and
Bureaucratic Surveillance - increase or reduce
monthly loyalty as well.
Terms of agreement[]
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Please help with verifying or updating this section. It was last verified for version 3.10. |
All subjects and overlords have an Agreement towards each other, which may include certain obligations for the subject or the overlord. Agreements may only be changed once every 5 years. Reforming the government to add the Feudal Society or
Franchising civics removes incompatible terms from all agreements. Many agreement terms are restricted by subject type, primarily
Tributary, or by the Suzerains and Sovereignty resolutions.
The influence cost to propose a change in the Agreement Terms is 50 + 5 for each point of immediate change in
loyalty; the total change in loyalty is summed across all terms, so that positive and negative changes can "cancel out" their costs.
For example, changing Holdings Limit from 0 to 1 (or vice-versa) changes loyalty by −5 and thus costs an additional 25 influence; similarly, changing from Sensors from Independent Sensors to Unified Sensors (or vice-versa) changes loyalty by +5 and so also costs an additional
25 influence; however, changing both Holdings Limit from 0 to 1 and Sensors from Independent Sensors to Unified Sensors "cancels out" the total loyalty change and thus costs no additional influence.
The initial terms of agreement for subjects created by the Subjugation and Imposed Inclusion casus belli as well as their starting
Loyalty are determined by the overlord's
Subjugation War Terms policy.
Terms | Effects | ![]() |
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Overlord requirements | Subject requirements | |
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Subject Integration | ||||||
Integration Permitted | Overlord can use the Integrate Subject interaction | −50 | −4 |
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Integration Prohibited | Overlord cannot use the Integrate Subject interaction | +5 | +0.5 | |||
Diplomatic Freedom | ||||||
Limited Diplomacy |
|
−15 | −1 |
|
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Restricted Voting |
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−5 | 0 |
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Independent Diplomacy |
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+5 | +0.5 | ![]() ![]() |
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Expansion | ||||||
Expansion Prohibited | Subject cannot construct outposts | −15 | −1 |
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Expansion Regulated | Subject must pay the overlord an additional 50% of the ![]() |
−5 | 0 | ![]() ![]() |
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Expansion Permitted | Subject can construct outposts | +5 | +0.5 | (unless A Voice for All resolution passed)
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Overlord Conflicts | ||||||
None | The subject joins none of the overlord's wars | 0 | 0 | |||
Defensive | The subject joins only the overlord's defensive wars | −1 | ||||
Offensive | The subject joins only the overlord's offensive wars | −2 | ![]() ![]() | |||
All | The subject joins all of the overlord's wars | −3 | ||||
Subject Conflicts | ||||||
None | The overlord joins none of the subject's wars | −10 | 0 | ![]() ![]() |
||
Defensive | The overlord joins only the subject's defensive wars | +5 | +0.5 | |||
Offensive | The overlord joins only the subject's offensive wars | +10 | +1 | ![]() ![]() |
||
All | The overlord joins all of the subject's wars |
+15 |
+1.5 | ![]() ![]() |
||
Holdings Limit | ||||||
0 | The overlord cannot construct any holdings across the subject's worlds | 0 | 0 | |||
1 | The overlord can construct 1 holding across the subject's worlds | −5 | −0.4 | |||
2 | The overlord can construct 2 holdings across the subject's worlds | −15 | −1 | ![]() |
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3 | The overlord can construct 3 holdings across the subject's worlds | −30 | −2 |
|
| |
4 | The overlord can construct 4 holdings across the subject's worlds | −50 | −4 |
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||
Sensors | ||||||
Independent Sensors | Subject does not receive sensor data from the overlord | −5 | 0 | ![]() ![]() |
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Unified Sensors | Subject receives sensor data from the overlord | 0 | +0.25 | (unless Borderless Authority resolution passed): |
Contribution[]
Contribution terms of agreement dictate whether the subject or the overlord will pay something to the other empire. They are adjustable in 15% increments as a proportion of the subject's income. A negative value means that the overlord pays the subject (a subsidy) and a positive value means that the subject pays the overlord (a tax). Any contribution other than 0% blocks regular diplomatic trading of those resources.
Type | Resources | ![]() |
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Minimum and maximum amounts | ||||||
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Basic | ![]() ![]() ![]() |
0 to −45 | +3.7 to −3.7 | −45% to +45% | +30% to +75% | +30% to +75% | −75% to −30% | −45% to +45% | +30% to +75% | −75% to +45% |
Advanced | ![]() ![]() |
0 to −45 | +3.7 to −3.7 | −45% to +45% | 0% to +75% | 0% to +45% | −75% to 0% | −45% to +45% | +15% to +75% | −75% to 0% |
Research | ![]() ![]() ![]() |
0 to −90 | +3.7 to −3.7 | −45% to +45% | 0% to +75% | 0% to 0% | −45% to +45% | +30% to +75% | −75% to −30% | −75% to 0% |
Strategic | ![]() ![]() ![]() |
0 to −135 | +3.7 to −3.7 | −45% to +45% | 0% to +75% | 0% to +30% | −45% to +45% | −45% to +45% | 0% to +75% | −75% to 0% |
A Bulwark or
Prospectorium's required subsidy (basic and research respectively) increases by 15% for each tier the subject reaches: 45% at tier 2, 60% at tier 3. Additionally, a tier 2 or 3 Prospectorium must pay at least a 30% tax of their strategic resources.
Subject types[]
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Please help with verifying or updating this section. It was last verified for version 3.10. |
There are five types of regular subjects, three types of specialized subjects and five types of fallen empire subjects.
Negotiable subjects[]
Type | Subject Requirements | Special Terms | Description |
---|---|---|---|
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A vassal is a subject of another empire, often with little to no self-rule. Having signed a pact with a foreign power, they are often at the whims and mercy of their overlord, forced to bend to whatever rules and regulations their liege wishes. For some weakened empires, this is the final stopgap before they are consolidated properly into the fold, as they are signing away their autonomy bit by bit. | |
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A protectorate is a subject that is considerably weaker than their overlord, reduced to the point where their vassalage is considered a boon to them. Protected from the dangers of the greater galaxy, they can stabilize and improve their homeland as their liege looks out for them. |
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A tributary is a fairly autonomous subject, still in charge of their own affairs both internally and politically. They pay a considerable amount of tribute for their overlord's protection, and as long as the money is flowing, they are mostly free to do whatever they want. | |
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A subsidiary is a subject with a considerable amount of self-rule, free to attend to their own affairs. They have signed away some of their independence for a deal where both sides are expected to support and aid one another. | |
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Subject contributes 30% of their ![]() |
A Satrapy is a Subject type continuing the traditions of the Great Khan that is obligated to provide their Overlord with both ships and resources. |
Specialized subjects[]
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Available only with the Overlord DLC enabled. |
Specialized subjects cannot be integrated and have additional effects. They can gain experience to increase in tier and gain additional effects. To reach tier 2, they need 1200 experience, and to reach tier 3, they need 3600 experience. Experience is gained monthly at a value of a tenth of the subject's loyalty. Empires with the
Imperial Fiefdom origin will become a specialized subject of their choice shortly after the game starts. Protectorates cannot be made into a specialized subject; any other regular type of subject can be turned into a specialized subject through the agreement screen.
Overlord effects do not stack if there are multiple specialized subjects of the same type. The Relay Network effects require a Hyper Relay connection between the overlord and subject's capital systems and only apply to overlord systems connected to the same Hyper Relay network.
Type | Effects for subject | Tier 1 | Tier 2 | Tier 3 |
---|---|---|---|---|
![]() Overlord gains:
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+50% | +50% | +75% |
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+50% | +50% | +75% | |
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+50% | +75% | +100% | |
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+50% | +75% | +100% | |
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−25% | −50% | −75% | |
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+5% | +15% | +25% | |
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+5% | +15% | +25% | |
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+2 | +5 | +8 | |
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— | — | −0.3% (−0.5% with ![]() | |
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−20% | −35% | −50% | |
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−20% | −35% | −50% | |
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−20% | −35% | −50% | |
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— | +1 | +1 | |
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— | +2 | +2 | |
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— | ![]() |
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— | ![]() |
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Technologies Unlocked | ![]() |
— | — | |
Technologies added as research options |
|
|
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— | — | ![]() | |
![]() Overlord gains:
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−10% | −25% | −50% |
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+10% | +20% | +30% | |
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+10% | +20% | +30% | |
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+10% | +20% | +30% | |
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+10% | +20% | +30% | |
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−30% | −40% | −50% | |
20% Yearly chance to discover a resource cache | Only ![]() ![]() |
Also ![]() ![]() ![]() ![]() |
Also ![]() ![]() ![]() | |
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— | +1 | +1 | |
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— | +2 | +2 | |
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— | ![]() |
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— | ![]() |
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Technologies added as research options | — |
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— | — | ![]() | |
![]() Overlord gains:
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+20% | +30% | +40% |
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+1 | +1 | +1 | |
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−30% | −40% | −50% | |
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+30% | +40% | +50% | |
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+30% | +40% | +50% | |
20% Yearly chance to discover a research cache | ![]() |
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— | +1 | +1 | |
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— | +2 | +2 | |
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— | ![]() |
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— | ![]() |
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— | — | ![]() |
Fallen empire subjects[]
Fallen empire subjects have preset terms of agreement. They do not allow subject integration or holdings.
Type | Proposing empire | Diplomatic Freedom | Expansion | Overlord Conflicts | Subject Conflicts | Resource Contribution |
---|---|---|---|---|---|---|
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None |
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None |
Luminarium[]
Luminarium is a subject type only possible for the Formless. The Formless gain +100% Jump Drive Range and −90% Jump Drive Cooldown and the overlord gains −50% Physics Research Cost. Aside from Contribution their terms of agreement cannot be changed.
Integration[]
Subjects that have Integration Permitted in the terms of agreement can be integrated into the overlord empire after 10 years via a diplomatic action, transferring ownership of the subject's systems, ships, and relics to the overlord; the subject's leaders, stockpiled resources, and armies are not transferred. Only one subject can be integrated at a time. Integration costs 5 influence per month and has a base cost with the following formula:
If the player empire is integrated, the game is automatically lost.
References[]
Exploration | Exploration • FTL • Anomaly • Archaeological site • Relics • Pre-FTL species • Fallen empire • Events • Spaceborne aliens • Enclaves • Guardians • Marauders • Caravaneers |
Celestial bodies | Celestial body • Colonization • Terraforming • Planetary features • Planet modifiers |
Species | Species • Traits • Population • Pop modification • Species rights • Ethics • Leader |
Governance | Empire • Origin • Government • Civics • Policies • Edicts • Factions • Technology • Traditions • Situations |
Economy | Resources • Planetary management • Districts • Buildings • Holdings • Jobs • Designation • Trade • Megastructures |
Diplomacy | Diplomacy • Relations • Galactic community • Federations • Subject empires • Intelligence • AI personalities |
Warfare | Warfare • Space warfare • Land warfare • Starbase • Ship • Ship designer • Crisis |
Others | The Shroud • L-Cluster • Unique systems • Preset empires • AI players • Easter eggs |