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Stellaris
Stellaris
4.3|Dec 19, 2025
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Stellaris 4.3 "Cetus" Open Beta Updated (2025-12-18)

5/5 Game-Changing

Stellaris 4.3 'Cetus' introduces a complete Refugee Attraction system and a massive overhaul of Naval Capacity, increasing ship usage by 5x while halving tech costs.

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Key Changes

  • 1Naval Capacity usage increased by 5x for most ships (Corvettes now 5, Battleships 40)
  • 2New Refugee Attraction system with specific modifiers for Ethics, Civics, and Origins
  • 3Unemployment rework: Pops now demote to lower strata immediately at month end
  • 4Tech costs halved across the board to compensate for reduced job-based research
  • 5Stability bonuses and job efficiency modifiers reduced by roughly 50% globally
  • 6Frigates buffed with Destroyer speed, +1 Utility slot, and +1 Aux slot
  • 7Armor and Shields now provide (Tier - 1)% Hardening
  • 8Crystal Hull plating now grants flat damage reduction (up to -8)
  • 9Cosmogenesis rework: Fallen Empires now directly oppose experiments, leading to Total War
  • 10Massive species trait rebalance, nerfing high-tier traits like Erudite and Dark Matter Engines

All Changes

🤝Refugee System(30)

  • newRefugees: Added 'Refugee Attraction' modifier to handle pop migration logic.
  • changeRefugees: Refactored refugee logic: pops now prefer empires where their species is dominant.
  • nerfFanatic Xenophobe: Fanatic Xenophobe ethics grant -30% Refugee Attraction.
  • nerfXenophobe: Xenophobe ethics grant -15% Refugee Attraction.
  • buffFanatic Xenophile: Fanatic Xenophile ethics grant +30% Refugee Attraction.
  • buffXenophile: Xenophile ethics grant +15% Refugee Attraction.
  • buffBeacon of Liberty: Beacon of Liberty civic grants +25% Refugee Attraction.
  • buffIdealistic Foundation: Idealistic Foundation civic grants +10% Refugee Attraction.
  • nerfSlaver Guilds: Slaver Guilds civic grants -25% Refugee Attraction.
  • nerfInwards Perfection: Inwards Perfection civic grants -50% Refugee Attraction.
  • buffFree Haven: Free Haven civic grants +50% Refugee Attraction.
  • nerfPompous Purists: Pompous Purists civic grants -25% Refugee Attraction.
  • nerfDystopian Society: Dystopian Society civic grants -25% Refugee Attraction.
  • changeSelective Kinship: Selective Kinship grants +30% attraction for same species class and -20% for others.
  • nerfExperimental Sentencing: Experimental Sentencing civic grants -15% Refugee Attraction.
  • buffMedia Conglomerate: Media Conglomerate civic grants +10% Refugee Attraction.
  • nerfIndentured Assets: Indentured Assets civic grants -25% Refugee Attraction.
  • nerfJudicial R&D: Judicial R&D civic grants -15% Refugee Attraction.
  • buffRogue Servitor: Rogue Servitor civic grants +30% Refugee Attraction.
  • buffBroken Shackles: Broken Shackles origin grants +100% Refugee Attraction.
  • nerfFear of the Dark: Fear of the Dark origin grants -10% Refugee Attraction.
  • nerfNecrophage: Necrophage origin grants -25% Refugee Attraction.
  • nerfCrisis Paths: All Crisis Paths grant -50% Refugee Attraction.
  • buffXeno-Compatibility: Xeno-Compatibility ascension perk grants +100% Refugee Attraction.
  • buffHarmony: Harmony - Kinship tradition grants +20% Refugee Attraction.
  • nerfPopulation Control: Population Control policy grants -10% Refugee Attraction.
  • nerfSlavery: Slavery Allowed policy grants -50% Refugee Attraction.
  • nerfDisplacement Purge: Displacement Purge policy grants -25% Refugee Attraction.
  • nerfPurge: Purge Allowed policy grants -90% Refugee Attraction.
  • buffGreater Good: Greater Good resolutions grant 10% to 50% scaling Refugee Attraction.

🚀Ships & Combat(18)

  • nerfCorvette: Increased Naval Capacity usage for Corvettes to 5.
  • nerfFrigate: Increased Naval Capacity usage for Frigates to 8.
  • nerfDestroyer: Increased Naval Capacity usage for Destroyers to 10.
  • nerfCruiser: Increased Naval Capacity usage for Cruisers to 20.
  • nerfBattleship: Increased Naval Capacity usage for Battleships to 40.
  • nerfTitan: Increased Naval Capacity usage for Titans and Bio-Titans to 80.
  • nerfJuggernaut: Increased Naval Capacity usage for Juggernauts and Colossi to 100.
  • buffNaval Capacity: Increased base Naval Capacity to 40.
  • buffPerdition Beam: Perdition Beams now deal AOE damage to ships within range of the target.
  • buffShip Components: Higher tier Armor and Shields now grant (Tier - 1)% Hardening.
  • buffCrystal-Infused Plating: Crystal-Infused Plating now grants flat damage reduction (-1 to -4).
  • buffCrystal-Forged Plating: Crystal-Forged Plating now grants flat damage reduction (-2 to -8).
  • buffFrigate: Frigates are now faster (Destroyer speed) and have +1 Utility and +1 Aux slot.
  • changeDisruptor: Disruptors now start with 50% bypass (scaling to 80%) and deal +25% damage to shields.
  • nerfNanotech Ships: Added nanite upkeep for nanotech ships.
  • changeAnchorage: Anchorages now provide +5 Naval Capacity (+8 with Logistics Office) but have Trade upkeep.
  • changeEternal Vigilance: Eternal Vigilance AP now grants +20% home territory ship fire rate instead of free platforms.
  • buffSiege Combat Computer: Torpedo Combat Computers renamed to Siege Combat Computers; grant up to +100% damage vs Starbases.

💰Economy & Jobs(12)

  • buffTechnology: Tech costs have been reduced by 50% across the board.
  • changeEmpire Size: Base Empire Size from pops halved; base size from colonies increased to 20.
  • changeUnemployment: Unemployed pops now demote to Civilian or Maintenance Drone strata at the end of the month.
  • removeUnemployment: Removed the 'Rising Unemployment' event chain.
  • nerfStability: Most stability bonuses have been reduced by 50% to 66%.
  • nerfJobs: Reduced job-based research production and most job efficiency modifiers.
  • changeSoldier: Soldiers are now Specialist jobs with 1 Alloy upkeep.
  • buffBureaucrat: Bureaucrat jobs now produce slightly more unity.
  • changeColony Ship: Private colony ships now use Trade for cost and upkeep instead of Energy.
  • changeAutomation Buildings: Automation buildings are now job-specific and no longer scale upkeep based on district count.
  • nerfEcumenopolis: Ecumenopoleis districts and Arcology Project now cost Alloys instead of Minerals.
  • changeStrategic Resources: Strategic resource production moved primarily to district specializations.

🏛️Origins & Civics(7)

  • nerfCosmogenesis: Cosmogenesis: Fallen Empires now oppose experiments, leading to Total War at Stage 5.
  • buffCybernetic Creed: Cybernetic Creed Factions now produce Minerals, Alloys, Consumer Goods, or Engineering.
  • buffStorm Chaser: Storm Chaser origin capital buildings now provide storm shelter effects automatically.
  • nerfGenesis Guides: Genesis Guides: Reduced rewards from colonizing to 250 Unity and 5 Influence.
  • buffSlingshot to the Stars: Slingshot to the Stars now provides -15% cost reduction for outposts (excluding Influence).
  • buffDark Consortium: Dark Consortium now starts with a larger Dark Matter deposit.
  • nerfVirtuality: Clustered Capacity (Virtuality) job efficiency reduced from +175% to +75%.

🧬Species Traits(7)

  • nerfErudite: Erudite: Researcher job efficiency reduced from +30% to +20%.
  • nerfFertile: Fertile: Pop Growth Speed reduced from +30% to +20%.
  • nerfVat Grown: Vat Grown: Organic Pop Assembly reduced from +33% to +25%.
  • nerfDark Matter Engines: Dark Matter Engines: Job efficiency reduced from +40% to +20%; upkeep increased to 0.03.
  • nerfMatrix Trading: Matrix Trading: Trade job efficiency reduced from +50% to +20%; upkeep increased to 0.02.
  • changeRare Crystal Exterior: Rare Crystal Exterior: Replaced +20% Metallurgist efficiency with +30% Habitability.
  • changeSpecies Traits: Strong, Very Strong, and Weak traits now affect Soldier efficiency.

🐛Bug Fixes(5)

  • fixEvent Ships: Fixed event ships failing to scale their naval capacity usage.
  • fixShip Limits: Fixed ship limits for Progenitor Hive, Titans, Colossus, and Juggernauts.
  • fixOvertuned: Overtuned is now correctly blocked from early genetic ascension.
  • fixDuelists: Fixed Duelists double-dipping on council position bonuses.
  • fixPlanet Forgers: Fixed Planet Forgers giving habitable worlds to origins like Shattered Ring.

🖥️Performance & AI(2)

  • changePerformance: Reduced worker tasks for thread pools to match physical cores instead of logical cores.
  • changeAI Behavior: AI empires now prefer having 3 or fewer underdeveloped colonies (<1000 pops) before expanding.

Summary

Refugee System Rework

The 'Cetus' update introduces a new 'Refugee Attraction' modifier that determines where displaced pops flee. This system replaces old logic with a more intuitive model where pops prefer empires with their own species or compatible ethics. Xenophile ethics and 'Free Haven' civics now provide significant attraction bonuses, while slavery and purging drastically reduce it.

Combat & Naval Capacity Overhaul

Naval Capacity has been fundamentally restructured. Most ships now consume 5x more capacity than before (e.g., Corvettes use 5, Battleships use 40), and base capacity has been increased to 40. Combat mechanics see the introduction of Armor and Shield Hardening on higher-tier components, and Crystal Hull plating now provides flat damage reduction. Frigates have been buffed with increased speed and extra slots.

Economic & Job Efficiency Rebalance

To address power creep, tech costs have been halved while job-based research production has been reduced. Stability bonuses and job efficiency modifiers have been cut by roughly 50% across the board. The unemployment system is simplified: pops now demote to lower strata immediately at the end of the month, removing the 'Rising Unemployment' event chain.

Origin & Civic Adjustments

Major balance passes have been applied to Origins like 'Cybernetic Creed' and 'Storm Chaser.' Cosmogenesis players will now face direct opposition from Fallen Empires, culminating in Total War at Stage 5. Additionally, high-tier species traits like Erudite and Dark Matter Engines have seen significant efficiency nerfs.

← OlderStellaris 4.3 "Cetus" Open Beta now availableDec 11, 2025Newer →Stellaris 4.3 "Cetus" Open Beta Updated (2026-01-15)Jan 15, 2026

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