This article is for the PC version of Stellaris only.
An Empire is a group of planets and star systems that are ruled by the same government and controlled by a single player (or AI). Empires may have a variety of governments such as a democracy, oligarchism, despotism or imperial rule.
Ethics are the most defining features of a space empire; they affect the behavior of AI empires, likely technologies, available policies and edicts, valid government types, the opinions of other empires, and - perhaps most importantly - provide the fuel for internal strife in large and diverse empires.
It should be noted that the name of the player empire and its government structure can always be changed in the government window.
The capital is the ruling seat of an empire and is oftentimes its most important world. An empire's capital can be moved once every 10 years for a cost of 250 influence and it will always have +100% governing ethics attraction as well as the option to build an Empire Capital-Complex, the highest level of administrative building. Certain buildings, such as level IV research labs and resource extractors, can only be built in the empire capital. Moving the capital or conquering another empire's capital downgrades an existing complex and removes capital-exclusive buildings.
An empire's capital planet and system are marked by star corners on the system and galaxy maps.
Core systems are those where the controlling player (or AI) manages the system's planets and buildings directly. As an alternative, players may assign systems into sectors by which planets micromanage themselves. The empire capital system is always part of the core systems and cannot be transferred to a sector.
All planets within core systems or a sector share the same leader slot (filled by a governor). The leader's bonuses provided by their governor traits are shared throughout the planets within that sector. Whether alien and slave populations can inhabit core worlds is determined by a policy.
The base number of maximum core worlds is 3. An empire may increase their core worlds via the following:
- +2 Pacifist ethic
- +4 Fanatic Pacifist ethic
- +2 Efficient Bureaucracy civic
- +2 Completing all Expansion traditions
- +1 Colonial Bureaucracy research
- +1 Galactic Bureaucracy research
- +1 Administrative Efficiency research (repeatable)
- +5 Imperial Prerogative ascension perk
|Available only with the Utopia DLC enabled.|
|Available only with the Utopia DLC or the Synthetic Dawn DLC enabled.|
If the number of directly controlled systems exceeds this limit, the empire suffers the modifier Inefficient Planet Management incurring −10% monthly influence and −10% monthly energy credits for every system above the limit.
A Sector is an autonomous administrative region under the control of a Governor. Sectors govern themselves independently of the player (or AI), though the empire remains responsible for the defense and protection of its sectors and can issue some priorities and orders to the sector government regarding construction of buildings etc. Sectors are created and managed by clicking on the empire tab at the top left of the screen. Sectors can be created and removed at will and can also be assigned a name.
Each sector has its own stock of energy and minerals. These stocks will be filled with sources within the sector's borders, except that some of its income are sent to the national stockpile depending on what tax level the player has selected for it. The sector's source of income can be taxed by 0/25/50/75% for Energy Credits or Minerals separately. Additionaly, sectors allow for the option to transfer 75% of the their stockpiled resources immediately at a 100 influence cost. The cost is reduced to 25 during defensive wars. Food, Research, Unity, and Strategic resources income are empire-wide and are, therefore, not stockpiled by sectors.
Sectors remain an integrated part of the empire, but handle development of planets and the construction of stations and defensive armies within their region themselves. Players can choose to set a a focus for them, which will influence their building path: balanced (no special focus), agricultural (focusing on food), industrial (focusing on minerals), research (focusing on research output) and financial (focusing on energy credits). They can be permitted or forbidden to replace existing buildings, requested to respect existing resource deposits, build orbital stations, spaceports, civilian ships, robots or to colonize planets available within the sector's borders.
The exact limit for direct control of planets depends on various factors, such as government type and technologies. The sector's capital will be the first planet added to the sector. Star systems can be added to and exchanged between sectors at any time, but each sector must always be a single contiguous region of connected space. If a sector becomes non-contiguous due to conquest or other actions a penalty will be applied to its production with a (-25% reduction in ).
The technologies to increase the maximum number of core worlds and sectors are both techs that may be researched repeatedly, although at an increasing cost. Sector limit gets increased by 1 for every 4 owned planets.
There is no limit to the number of stars within a given sector.
Empire Modifiers are gained through a variety of actions such as event choices or diplomacy with enclaves. They affect the entire empire and as such bring large benefits or penalties.
Permanent Empire Modifiers are always positive and last the entire game. They can only be gained through events.
Renewable Empire Modifiers are always positive and last as long as an empire can afford their upkeep costs.
Victory conditions are predefined goals that ensure victory of the game. In single-player mode, victory conditions are disabled if the game is started without AI players.
There are three ways to achieve victory in Stellaris:
- Domination, which requires owning 40% of all colonizable planets. Those owned by vassals and tributaries count while planets owned by allies and federation members do not.
- Conquest, which requires conquering or subjugating all independent empires except for fallen empires. In singleplayer Conquest victory is disabled if the game is started without AI players.
- Federation, which requires all members of a single federation to collectively own 60% of all colonizable planets. A human player can only win by this method while holding the federation presidency.
Any independent empire, even an AI empire, can declare victory. However, AI empires do not pursue these victory conditions and can only meet them coincidentally, as driven by their AI personalities. Vassals and protectorates cannot claim victory under any circumstances.
All players may continue the game session normally even after an empire declares victory.