I've been curious about the Sophon armor/spacesuits that we always see them in. Are they personalised life support? Temperature control? What do they look like under there? 

The suits probably do a wide variety of things from basic life support to displaying data for them and recycling sweat into drinking water. They are hyper-efficient researchers, after all, so less distractions means more productivity.

Underneath the suits they probably look a lot like your stereotypical "little gray alien." Their suit design (especially in the first game!) seems like it draws heavily from that idea.

Endless Space 2: Early Access - Sophon's Vision Official Cinematic 

At 0:35 you can see what they look like underneath 

And Dragontyron basically hit it on the head with his explanation; the suits are all around life support suits and provide basic functions as well as constant HUD feed. On top of that, the Sophons are known to have quite frail bodies so the suits likely double as protective armor. 

Thanks!

Of course!

Good trailer I`m wondering why it didn`t make it into the game. Could be a good intro to tell at least a bit more about the universe.

There is also the possibility that the suits display all types of social media and video games on the HUD. After all, the Sophons are pretty consumerist, at least among the younger generations.

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