The vortiguants in Half-Life have the green things around their necks and arms which possibly signifies that they are enslaved (by the Combine, perhaps). I just played the Xen portion of the original game and there are areas with barrels with alien grunts in them, it looks like they are “manufactured” there. Do you think it is possible that the grunts are basically vortiguants altered and cloned by the Combine, the same way as people are made into overwatch soldiers?
It might be possible, allthough I think they are two different verisions of the same race, since they both have a third arm on their chest. But I think that the grunts are just Vort soilders, without the Vortigaunt powers of lightning. They do fight together and not against each other. And in the factory-part of Xen, we can see the Grunt “eggs” being manufactured and guarded by Vortigaunts, so my final guess is that Nihilanth uses Vorts as slaves, or combine uses vorts as slaves, to create stronger soilders. The nihilanth also looks enslaved when you look closely.
yeah I agree, alien grunts are thee… “CombineSoldiers” of xen, and Vortigaunts are the “enslaved humans” as well Nihilanth is the “Dr.Breen” who oversees operations in xen for the combine
Replace “Combine” with “Nihilanth” and that’s the general consensus.
Also, The Combine are nowhere to be found in Half-Life. They literally do not enter the story until the 7 hour war. The Nihilanth is on the run from The Combine. The only reason he invades Earth when the experiment fails (or succeeds, in Gman’s eyes) is because it can put one more step between himself and The Combine. People generally believe that The Combine are the reason Nihilanth has metal bits sticking out of his backside, as well as the scars he has.
We’ve been talking about this stuff since the mod was announced. We’ve (and others not on this forum) asked Mark Laidlaw (the guy who wrote Half-Life and Half-Life 2) just about everything we could think of. This info might not be the most accurate, but it’s probably as close as you’re going to get without being Mark Laidlaw.
Vortigaunts/Alien Grunts and Controllers/Nihilanth are somehow connected.
Nihilanth was created by Combine along with controllers to control Vorts and gain control of Xen.
Nihilanth went rogue.
Nihilanth enslaves Vorts, using them to create biologically altered monstrosities of themselves, the grunts.
not bad, but that’s only one of many possible theories.
It wouldn’t have been to get control of Xen - the Nihilanth fled to Xen to escape the Combine.
So? If they created the Nihilanth in order to gain control of Xen and the Vorts it shows they have no other way of getting there. Hence it being the perfect place for the Nihilanth to hide.
It’s one of many possible theories sure, but imo it’s the only one that has any semblance of sense at all ( that I’ve heard ).
True, I didn’t think of it that way. 
Although IIRC Marc Laidlaw said the Nihilanth had never been captured by the Combine, so there is that.
I’ve been thinking about it recently and generated a theory that perhaps it was created by the vorts in their own Black Mesa/Aperture Science style incident, possibly as a way of defending themselves against enslavement by the Combine, but in the end it enslaved them instead.