Subject empire

Version

This article has been verified for the current PC version (3.2) of the game.

A subject empire is an Empire that has a special diplomatic relationship with another empire of superior strength. In the default galaxy map mode subjects have the same color as their overlord.

An empire can become a subject either forcefully through wargoals or willingly, though the latter requires both a superior relative power and a positive attitude towards the superior party. If an empire becomes a subject willingly it brings a temporary +30 Opinion. If it becomes a subject forcefully it brings a temporary -30 Opinion

If they have fleets available, subject fleets tend to follow the overlord's.

Subject types

There are a number of types of subjects available depending on the overlord's government. Most of them have to pay a certain tribute to the overlord.

Type	Tribute	Intel	Other effects	Overlord requirements
Tributary	25% Energy income 25% Minerals income	30		Corporate
Vassal		40		Corporate Less than 50% technological superiority Neither empire has Inward Perfection
Protectorate		40	Subject gains −80% Research Cost towards technologies researched by the overlord Overlord gains +0.25 Monthly Influence Subject cannot sign Research Agreements At less than 50% Technological Level difference the Protectorate becomes a Vassal	Corporate More than 50% technological superiority Neither empire has Inward Perfection
Subsidiary	25% Energy income	40		Corporate authority
Dominion	25% Energy income 25% Minerals income	30	Ethics are shifted towards Fanatic Spiritualist if not Gestalt Consciousness	Doctrinal Enforcers awakened empire
Satellite	33% Research income	30		Watchful Regulators awakened empire
Signatory		30	Slavery and Purge policies stay set to Prohibited	Benevolent Interventionists awakened empire
Thrall	25% Energy income 25% Minerals income	30		Jingoistic Reclaimers awakened empire
Scion		40	Can use the Bring Into Fold Wargoal	Scion origin
Satrapy	10% Energy income 20% Minerals income 30% Naval income	10	House a Void Dwelling in the capital system	The Horde Subject didn't rebel before

If an empire switches its authority to or from Corporate, its subjects' types are changed.

Subject actions

For subject empires the attitude is replaced by loyalty, expressing how content they are living under their Overlord’s rule. If a subject becomes disloyal they refuse any deal with the overlord and have a chance to start a war for independence, always waiting for an opportunity when something depletes the overlord's relative power (a taxing war, a larger uprising, a crisis, etc.). The loyalty is determined by the subject's opinion of the Overlord, which aside from the normal factors is also affected by the total military strength of all the subjects relative to the Overlord as well as that of those who support their independence.

An Empire is able to support the independence of another Empire's vassal. Doing this will count the supporting empire's fleet for the "relative power of subjects" opinion modifier, causing the subject to rebel if they stand a good chance of victory. If they do, the Empire supporting them automatically joins their war for independence.

Subject empires do not suffer from border friction and can therefore in some cases be utilized as buffer states between two empires that otherwise would have significant border friction issues.

The opinion penalty from Relative Power is reduced by 50% with the Feudal Society civic and by 33% with the Franchising civic.

Integration

Vassals and Protectorates that an empire possess for longer than 3 600 days can be peacefully "integrated" by paying influence, at a rate of 5 influence a month. The base cost is 50, increased by 1 for each pop and 10 for each planet. Empires with the Shared Destiny ascension perk benefit from a -50% influence cost to integrating subjects. Only one subject can be integrated at a time.

Once the integration is completed, all planets and ships of the subject are transferred to the overlord; the ships and starbases retain their graphic type. All leaders, resources and armies are removed; new scientists are required for their science ships.

Warning! If the player's empire is integrated by another empire the game is automatically lost!

Releasing as a vassal

A player can create a vassal from their own territory by releasing one of their sectors as a vassal from the "Sectors" tab by clicking the "Create Vassal" button next to the sector they want to release. The player can then transfer additional systems to their vassal through the Trade option "Transfer System" if they so choose.

Sometimes it is preferable to conquer systems and then release them as a vassal since this will create a vassal that shares the overlord's ethics and government. Notably, the vassal will be granted all its overlord's technology. The option to release a vassal is not available to Machine Intelligences (except when you have no robot pops in the sector), Genocidal empires, species with Stellar Culture Shock, or the Hive-Minded and Nerve Stapled traits.