Concept: Wormhole Junktion

[ViolentBeetle]

Place between 2 and 6 special systems on the galaxy. Flag them as empire cluster to prevent wormholes.
Upon surveying the star, trigger an event talking about some exotic particles and pin wormhole tech.
Add a tech that has wormhole tech as well as controlling one of the special systems as prerequisite.

Researching tech enables special project to activate wormhole junction in one of the special systems. Upon completion, an extragalactic cluster is spawned and connects with all special systems.

Junction cluster is composed of 7 systems in star formation. 6 systems for wormholes (If there's less than 6 destinations, only some spawn wormholes). Wormhole systems are generic (Something along the line of 1 star 3-8 planets) and central system is special. How special it is random. Possible outcomes include.

• Nothing. The cluster is empty. Central system has guaranteed habitable planet.
• Crystal infestation. Lost of crystals are placed in all cluster systems. Central system contains Gaia world.
• Quarantine. Tempset-like squadrons cover the entire cluster. one squadron flies to each system outside the cluster and hold postion there. Central system has relic world with bronze age primitives on it.
• Rampager. Central system contains a powerful space station and a ship. Ship contains an immortal admiral who goes to attack one of the wormholes and starts attacking adjacent systems until it is killed. When killed, respawns more powerful. Naturally deprioritizes those who killed him recently as well as country that opened the cluster (Temporarily). One must take out the station to end this.
• Emerald Empress. A unique green dragon guarding a primitive planet who are her pets. Drops relic when defeated.
• Remnants. The guys from rebel_yell chain with their fancy ships as a non-playable nation (gatebuilder copy?). Neutral by default but hostile if you in war (Their cluster is not to be used in war). Stay hostile if you kill enough of their ships. Control sparsely populated ecumenopolis. You can repatriate the princess so they would stop turning hostile.