Combine overworld

From Combine OverWiki, the English Half-Life Wikia

"Attention: Mission Failure Will Result In Permanent Off-World Assignment" - Overwatch Dispatcher

Very little is known about the Combine homeworld known as the Combine Overworld, as it has never been directly mentioned in any of the Half Life games, exept for a vague outburst by Arne Magnusson in the chapter To The White Forest.

Through the portal at the end of Half Life 2 a skyline of many Citadels can be seen. Also, the sky is red, but that may be from the color of the portal.

What little information or speculation that can be made suggests that the Combine Overworld's climate is very different from that of Earth, as all Combine species seen so far feature a sort of breathing apparatus (The Advisor has a small black cup over its snout and the Combine Overwatch all feature obvious masks). This suggests that the Combine Overworld does not support oxygen or nitrogen, the primary gases of Earth's atmosphere. When Breen escaping through the portal at the end of Half Life 2 is mentioned that he could not survive in the environment beyond the portal, and Advisor (presumably) says he could do so with a new 'host body' which Breen accepts.

This raises interesting questions as to why the Combine are interested in occupying Earth. One answer to this is Combine's apparent need to drain Earth of its resources. Although this could be because it is a very old world that can no longer support the needs of the Combine. The age of the world is supported by their level of advanced technology, though they may have stolen it.