Stellaris – How to Vassalise

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Players of other Paradox Interactive games may already be familiar with the concepts of vassalising another state. Stellaris also has a vassal system that empire leaders can make use of.

Vassal is a fancy word for subject; if an empire is your vassal, you are their boss for intents and purposes. Likewise, if you have an overlord, you are their subject and are beholden unto them.

Recommended Read: Stellaris – What Are the Best Ethics?

There are many different forms of vassal, some evil and others benign. When the Overlord DLC was released in 2022, the vassal system received a massive overhaul. This guide will teach you how to acquire your own vassals for your empire.

To make another empire your vassal in Stellaris, you can either ask them peacefully with diplomacy or subjugate them using force. The other way to create a vassal is by releasing one of your sectors to form its own subject empire.


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How to Vassalise in Stellaris

Most mechanics that involve getting another empire to do something have two solutions. The diplomatic way and the diplomatic way that involves blowing up each other ships. Getting other empires to become your vassal is no different.

Getting empires to accept your terms, or even having the opportunity to invade them, will depend on both empires’ relative power

Having a power rating that is superior or overwhelming makes the target empire much more likely to accept becoming a vassal.

How to Vassalise With Diplomacy

Contrary to popular belief, violence is not the only course of action in Stellaris.

The galaxy is infested with enough dangers, so intelligent species shouldn’t be waging war on each other. Empires recruited this way are far more likely to be loyal and compliant to their overlords.

The AI does not want to be a subject if it can avoid it, and getting them to accept will not be an easy task. The factors that determine acceptance are opinion, relative power, and potential threats.

The perfect situation to be in is; your empire is powerful, you are allies, and there is a threat; such as a genocidal empire close by.

The AI will be glad to accept the protection of your empire to keep itself alive. They may even ask to be your vassal before you even have the chance to offer it to them.

To request an empire to become your vassal, first, you will need to contact them via the diplomacy screen. Navigate to the Propose Subjugation option. This will open the vassal contract menu.

Edit the contract as you see fit, and it will have either a red cross or a green tick. If it has a tick, congratulations, they will accept your offer, and you have a new vassal.

If there is a red cross, they will not accept your offer, and you will have to make a few changes to the contract or something else.

Hovering over the cross will display the maths the game has used to come to that decision. The empire may hate you, or the fact that you are not that much stronger than them may be the contributing factor. Change that, and they will soon accept your polite offer.

Not all empires can become vassals. A genocidal empire, for example, will never entertain a subjugation offer. They only want to kill you, not pay homage.

Subjugation Using War

For some players, peace was never an option. Other empires can be bullied into subjugation using your own military might. Not all empires will accept a peaceful resolution, and war is the only way to integrate them.

If your relative power rating to the target empire is superior or overwhelming, you will gain the subjugation Casus Belli. Empires recruited this way will not be happy. Future subjects will have to be closely monitored for signs of insurrection.
To win this war, you will need to occupy all the future subjects systems and invade all of their planets. Once they surrender, you are now their new overlord and can edit their vassal contract as you see fit.

Creating a Vassal Out of A Sector

Sectors are microstates within your empire that you appoint a governor to oversee. You can let them be autonomous, but ultimate control of the sector still belongs to the player.

You may decide to do this if; the size of your empire is becoming a bit difficult to manage or you have gained a sector too far from your empire’s main border to defend properly.

For whatever reason you decide, you can release sectors to form their own subject empires.

The vassal contract must be accepted by the new empire and, as such, can be whatever you want it to be. If you change your mind, you can re-integrate your new vassal back into the empire by paying an influence cost.


That is everything you need to know about how to vassalise in Stellaris.

If you have any questions or suggestions for this guide, please let us know in the comments below. As always, have fun subjugating the galaxy in Stellaris.

Simon Neve

Simon lives in Northern Ireland with his wife and two children. When not caring for his family, Simon enjoys video games, board games, and tabletop roleplaying games. When playing isn't an option he writes about them instead.

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