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When Do The Unbidden Appear?
How To Defeat The Unbidden
Who Are The Aberrant And The Vehement?
In Stellaris, the Unbidden are beings from a dimension of pure energy. These extradimensional invaders come to the galaxy in an attempt to make the universe similar to theirs - regardless of what that means for its inhabitants. Their ships have some of the game's most dangerous weaponry, making them a particularly powerful foe.
Related: Stellaris: How To Defeat The Contingency
The Unbidden will arrive without warning, so you may need to adapt your strategy on the fly if this Crisis suddenly triggers. Defeating them requires strong fleets of your own, along with advanced technology and a healthy dose of tenacity.
When Do The Unbidden Appear?
The Unbidden can appear in the galaxy any time after the campaign's Endgame Year. This is chosen during New Game setup, and by default the Endgame Year is 2400. The more time passes after that point, the more likely it is that a Crisis will occur. The Unbidden will never threaten the galaxy if the Contingency or the Prethoryn Scourge have already done so.
The chance of the Unbidden appearing increases if any empire has researched Jump Drive or Psi Jump Drive, or if the Galactic Council has passed the Extradimensional Experimentation resolution.
Unlike the Contingency and the Scourge, the Unbidden Crisis begins with no warning given to any empire. The first Unbidden Starbase will simply spawn in a random system, destroying and replacing any existing Starbase. Every player will receive a notification when that happens, but at that point, the invasion has already begun.
The location of the Unbidden's spawn point, the Extradimensional Portal, is revealed to all empires thirty days after it opens. If it's within sensor range you might be able to see it before that point, but if it's close enough to pick up on sensors your nearby systems are in terrible danger.
Related: Stellaris: Psionic Ascension Guide
How To Defeat The Unbidden
The Unbidden aren't interested in conquering planets and will simply bombard them until they become Barren Worlds. Their goal is to establish Starbases in as many systems as possible, eventually conquering the entire galaxy. As they expand, the invaders will construct Dimensional Anchors which stabilize their main portal. The location of all Dimensional Anchors can always be seen in the Situation Log.
The Unbidden's overall power will snowball quickly during the early parts of their invasion, since they get faster reinforcements the more systems they control. The overall size of the Unbidden navy is around two thousand ships, and they will not receive reinforcements if they are above that limit.
Unbidden ships use Matter Disintegrators, extremely powerful energy weapons. Shields are therefore critical for surviving any engagement with them. When the Unbidden first appear, refit all of your ships by replacing any Armor with the best Shields you can get.
Sending Science Ships to investigate the debris after a fight with the Unbidden can give you a chance to develop Matter Disintegrators of your own. They're not great against the Unbidden, but will be an exceptional weapon against rival empires once the Crisis is resolved.
The Unbidden make heavy use of Shields themselves, but their ships have no Armor. Autocannons, railguns, and missiles are therefore very effective against them, as are Disruptors. Unbidden fleets are glass cannons, fragile if you have the right counters but capable of devastating firepower.
The only way to stop the Unbidden is to destroy the Extradimensional Portal. It is always heavily defended, and cannot be destroyed until all the Unbidden's Dimensional Anchors are neutralized. Destroying the Portal earns the Rift Sealed Achievement / Trophy. The Unbidden will no longer receive reinforcements, but any remaining fleets and stations must be eradicated to end the Crisis.
Related: Stellaris: How Does Space Combat Work?
Who Are The Aberrant And The Vehement?
If the Unbidden successfully take control of fifteen percent or more of the galaxy, a second and third Extradimensional Portal will open over the next few years. Each Portal spawns a different faction of invaders, the Aberrant and the Vehement. Both are independent factions that function identically to the Unbidden, essentially doubling and tripling the threat to the galaxy upon their arrival.
If the Aberrant and Vehement arrive, the Crisis will not end until all Extradimensional Portals are destroyed. However, destroying a Portal will eliminate the owning invader faction's reinforcements, so it's worth focusing on the weakest one to take it out as quickly as possible.
Despite having the same goal of conquering the galaxy, the Unbidden, Aberrant, and Vehement are enemies of one another. The three factions will fight each other if their fleets meet, potentially providing an opening for the galaxy's defenders to exploit.
Next: Stellaris: How To Defeat The Prethoryn Scourge
