Piratez Lore

[JustTheDude/CABSHEP]

Every race besides Mutons looks fairly diffrent from humans. Mutons have "perfect" proportions and shape of a human. Feets looks just like ours, hands also (three fingers, but well... "Aliens"), just like insides (without cybernetics). Only their face looks very diffrent. I have two theories that in my opinion fits best:

Mutons are abducted humans "mutated" (As their name can hint "Muton" = "Mutated") with some alien gene and then with purple skin grafted on them and green suit on top of that.

Second (and more probably) theory is that Mutons are mutated Cydonians, race that inhabited Mars, but lost with Ethernals.

[Martin]

Notice that muton and ethereal faces are similar, when you look at the autopsy picture the ethereal looks like starved muton with closed eyes and some funny growths around her (or his?) neck. These might be vestigial external gills, suggesting aquatic larval stage. The muton lacks these, so theither they were surgicaly removed or the ethereal is neotenic.

[JustTheDude/CABSHEP]

Check the imagine of Muton's autopsy and it's description. They have special "skin" grafted to their body and on the imagine you can see it's left eye and area around it is light-blue - Original skin of Mutons.

Mutons are the only humanoid alien that can't close their eyes. They also lack "cheek" bones of Ethernals. Also they lack nose, unlike Ethernals.

Mutons from intro are more detailed and more differences can be seen.

They might originate from the same species with Ethernals discovering their Psychic potential and enslaving lesser brothers.

[Martin]

Looking at the into, the overall skull shape still looks reasonably similar with very thin jaws barely half the width of the upper face, with muton having massive mastication muscles the ethereal (who are mentioned to suffer form severe muscle athropy) lacks. In the intro, the red muton is shown blinking, so obviously they can close their eyes (not being able to do so woudl be a critical design flaw for a cyborg soldiers anyway)

[Solarius Scorch]

While I don't think it's canon, and I don't know if it should be canon, I think the Mutons being genetically related to Ethereals (or even the same species) is possible.
Now I'm trying to decide if this idea is genius or lame.