Stellaris – How to Vassalise

How to Vassalize in Stellaris

In Stellaris, as in other Paradox Interactive games, players may already be familiar with the concept of vassalizing another state. Just like in other Paradox games, Stellaris also has a vassal system that empire leaders can utilize.

A vassal is essentially a subject; if an empire becomes your vassal, you become their boss in all but name. Similarly, if you have an overlord, you become a subject and owe allegiance to them.

With the release of the Overlord DLC in 2022, the vassal system in Stellaris underwent a significant overhaul. This guide will teach you how to acquire your own vassals for your empire.

How to Vassalize in Stellaris

Most mechanics in Stellaris that involve getting another empire to do something have two solutions: the diplomatic way and the way that involves blowing up each other’s ships. Vassalizing other empires is no different.

The likelihood of other empires accepting your terms, or even giving you the opportunity to invade them, depends on the relative power of both empires.

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

How to Vassalize With Diplomacy

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

The galaxy is already filled with enough dangers, so intelligent species shouldn’t be waging war on each other. Empires that are recruited through peaceful means are far more likely to be loyal and compliant to their overlords.

The AI in Stellaris doesn’t want to be a subject if it can avoid it, so getting them to accept becoming a vassal will not be an easy task. The factors that determine acceptance include opinion, relative power, and potential threats.

The perfect situation to be in is when your empire is powerful, you are allies, and there is an imminent threat, such as a genocidal empire nearby.

The AI will gladly accept the protection of your empire to ensure its survival. They may even ask to become your vassal before you have the chance to offer it to them.

If you want to request an empire to become your vassal, you will need to contact them via the diplomacy screen. Then, navigate to the Propose Subjugation option, which will open the vassal contract menu.

Edit the contract according to your preferences, and it will either have a green tick or a red cross. If it has a tick, congratulations, they will accept your offer and become your new vassal.

If there is a red cross, it means they will not accept your offer, and you will have to make some changes to the contract or consider other factors.

Hovering over the red cross will display the calculations the game has used to make that decision. The empire may hold animosity towards you, or the fact that you are not significantly stronger than them might be a contributing factor. Make the necessary adjustments, and they will soon accept your offer.

However, not all empires can become vassals. For example, a genocidal empire will never entertain a subjugation offer since their only objective is to eradicate you, not become subjects.

Subjugation Using War

For some players, peace may never be an option. Other empires can be coerced into subjugation through military force. Not all empires will accept a peaceful resolution, and war becomes the only way to integrate them.

If your relative power rating compared to the target empire is superior or overwhelming, you will gain the subjugation Casus Belli. However, empires recruited through war will not be happy subjects. They will need to be closely monitored for signs of insurrection.

To win this war, you will need to occupy all the systems of the future subject empire and invade all of their planets. Once they surrender, you become their new overlord and can edit their vassal contract as you see fit.

Creating a Vassal Out of A Sector

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

You may decide to release sectors to form their own subject empires for various reasons. For example, if the size of your empire is becoming difficult to manage or if you have gained a sector that is too far from your empire’s main borders to defend properly.

Whatever your reasons, you can release sectors to form their own subject empires. The vassal contract must be accepted by the new empire, and as such, it can be customized to your liking. 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 vassalize in Stellaris.

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