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"Somewhere in that sequence, they would have had to establish a connection with the far side. What you have there young lady, is the specific contact code for the Combine Overworld."
Arne Magnusson[src]

The Combine Overworld is apparently the Combine's original homeworld, although this might also be another world conquered by the Combine. Dismaying the fact that it might have been another world conquered by the combine, there is a very strong possibility that maybe there could be a citadel in every 314 planets that the Combine had overtaken, but that could be wrong. It is also possible that, due to the multiple citadels seen, the Combine Overworld is not a traditional planet, but rather, a sort of interdimensional hub.



The Citadel model ("portalspire.mdl") used in the map.

Very little is known about this world, as it has never been directly mentioned in any of the Half-Life games, except for a vague outburst by Arne Magnusson in the Episode Two chapter To The White Forest.

Through the portal seen at the end of Half-Life 2, an orange skyline of what appears to be many Citadels can be seen. This is probably the Combine Overworld. The two Combine Gunships attacking Gordon come from that location, hinting Synths are also built there.

The Combine Overworld's climate seems to be different from that of Earth. The Advisor for instance has a small black cup over its snout, suggesting it cannot breathe Earth's air. All Overwatch forces have completely airtight outfits, even though the wearers are humans on Earth; this suggests that although they do not need it on Earth, it could be useful in other locations such as worlds with a different atmosphere (although the outfits do not feature oxygen tanks). The Overwatch Voice also tells several times to Overwatch troops that "mission failure will result in permanent off-world assignment", hinting any Overwatch unit is meant to be able to operate in other Combine-controlled worlds, the Overworld itself or other unknown Combine colonies. This suggests that the Combine Overworld does not support oxygen or nitrogen, the primary gases of Earth's atmosphere. Before Breen attempts to escape through the portal at the end of Half-Life 2, he says to an Advisor that he cannot survive in the environment beyond the portal; the Advisor (presumably) answers he could do so with a new 'host body', which Breen hesitantly accepts.

Behind the scenes

In the original final showdown conversation at Breen's office, Breen was to mention the "Aleph universe" as the universe Eli and Alyx were to be sent;[1] this might be referring to the Combine Overworld. Interestingly, "Aleph" is the name of the main protagonist of Prospero, Valve's first game project, that the team probably recycled for it.[2] "Aleph" is also the name of the first letter in the Hebrew, Arabic, and Persian alphabet, which makes sense as the homeworld is the "first" world.


Overworld through portal

The in-game appearance of the Combine Overworld in Half-life 2.

  • The Citadels seen through the portal are very similar to an early version of the City 17 Citadel used in cut propaganda posters.

List of appearances


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