''Warning: Here be heavy spoilers. More is to come.''

[[foldercontrol]]

[[folder: Player Characters]]
!!'''Dr. Gordon Freeman'''

[[quoteright:300:http://static.tvtropes.org/pmwiki/pub/images/rsz_half-life-gordon-freeman-alyx-vance-hd-wallpapers_979.jpg]]

->'''Age:''' 27.
->'''Education:''' [=PhD=] in Theoretical Physics, [=MIT=].
->'''Employer and Position:''' Black Mesa Research Facility, Research Associate.
->'''Assignment:''' Anomalous Materials Laboratory.
->'''Clearance:''' Level 3.
->'''Administrative Sponsor:''' Classified.
->'''Disaster Response Priority:''' Discretionary.

->'''Voiced by:''' [[TheVoiceless Nobody.]]

The main hero of the ''Half-Life'' series, Gordon Freeman is, at the point where ''Half-Life'' begins, a recently graduated scientist who is about half a hour late for an experiment, taking place deep within the Black Mesa Research Facility. If only he had known that it would soon become the least of his worries that day...

Finding himself at the ground zero of a disaster, trapped between an invasion of aggressive creatures from the dimension Xen and a shadowy military force that wants him and his colleagues dead, Freeman manages to battle his way across the facility in the span of two days, staying alive against all odds, aided by his HEV suit and staunch determination. He is eventually teleported to Xen, where he takes on the leader of the aliens, after which he finds himself face to face with the mysterious G-Man, who offers him a job.

Displaced by G-Man in time and space, Gordon suddenly finds himself in the so-called "City 17", in some undisclosed part of Eastern-Europe two decades after the events at Black Mesa. He discovers that Earth has been conquered by an alien empire called "The Combine", who rules their new colony with an iron fist, and he quickly manages to run afoul of them and is soon hunted by their military. But he also finds out that some of his old friends from Black Mesa has organized a resistance group that fights against the regime, and that he himself has become a revered and famous figure for the rebels due to his actions at Black Mesa. Together with the resistance fighter Alyx Vance, he ignites a full-scale rebellion against the Combine, and manages to bring down their central control-center on Earth.

In the wake of the overthrow of the Combine control, however, Gordon and Alyx, along with the rest of the rebels, soon finds themselves engaged in a even more bloody and desperate struggle to defeat the remaining Combine forces on Earth, and, even more importantly, preventing them from contacting the empire proper for reenforcements...

* AsskickingEqualsAuthority: By the time of VideoGame/HalfLife2, he doesn't have any definitive rank in the rebellion, but he pretty much commands any rebel squads he comes across, who are all too willing to ZergRush a position if he so much as looks at it, all because he's good at killing things.
* {{Badass}}
** BadassBookworm: His doctoral thesis is ludicrously titled ''"Observation of [[OurWormholesAreDifferent Einstein-Podolsky-Rosen]] Entanglement on [[TeleportersAndTransporters Supraquantum Structures]] by Induction Through Nonlinear [[GreenRocks Transuranic Crystal]] of Extremely Long Wavelength (ELW) Pulse from [[YourHeadAsplode Mode-Locked Source Array]]"''. In laymen's terms... looking at teleportation effects on crystals when you fire lasers at them. Which suspiciously sounds like the experiment you are conducting at the start.
** BadassBeard
** BadassNormal: Regularly fights his way through augmented transhuman soldiers and super powered aliens.
* CrowbarCombatant: Provides the trope image.
* TheDreaded: He steadily builds up a reputation throughout his adventures in Half-Life; by the midpoint of the game, the marines know exactly who he is and are actively hunting for him specifically. By the end, the Nihilanth is able to directly address him by name.
-->'''Nihilanth''': '''''FREEEEEEEEEEEEEEMAAAAAAAAAAN!'''''
* [[DidYouJustPunchOutCthulhu Did You Just Kill The Nihilanth?]]
* DudeWheresMyRespect: Averted. His reputation actually seems to do more work than him. He's pretty badass, but it was his reputation, not his actions, that caused most of the rebellion on Earth against the Combine.
* FamedInStory: By ''Half-Life 2''.
* TheHero
* HeroicMime: The whole time.
** Exception would be when he was breathing during the Black Mesa Incident, if that counts.
** In ''Half-Life 2'', Gordon also utters mild grunts of pain sometimes when he's on fire or falls from leg shattering heights.
** Alyx lampshades it early on when they meet: "Man of few words, aren't you?"
* IconOfRebellion: In ''2''.
* ImplacableMan: Gordon Freeman didn't really ''mean'' to save the world by slaughtering hundreds of soldiers and aliens at Black Mesa. They were just in the way of the exit.
* InformedAbility: Gordon is a theoretical physicist, but the most technically complex things he does in the games are plug machinery in and solve rudimentary physics puzzles. [[FridgeBrilliance Of course, his young age most likely means he only got his Ph.D. a couple years ago at most, so he wouldn't have had time to rise very high in the Black Mesa hierarchy before all hell broke loose.]] Barney [[LampshadeHanging hangs a lampshade on that]] in the second game.
--> '''Barney:''' Good job, Gordon. Throwing that switch and all? I can see your MIT education really pays for itself.
* LightningBruiser: He can take quite a bit of punishment, thanks to the suit, but can also run at ridiculous speeds and carry more firepower than the 82nd Airborne.
* LivingLegend
* MemeticBadass: InUniverse and out!
* NiceJobBreakingItHero: The entire Black Mesa Incident, duh! Well, all Gordon did was push the crystal in. But still, all hell broke loose on his watch.
* RightManInTheWrongPlace: The TropeNamer, as described by the G-Man.
* PoweredArmor: His HEV Suit.
* OneManArmy: While his suit is a big part of it (it gives him about 4 times as much health as a regular soldier when fully charged, can automatically reload his holstered weapons, and applies morphine and other assistance to [[CriticalExistenceFailure keep him going at full strength even when badly wounded]]), it is still pretty amazing considering he is just a scientist.
** The best example is probably at the end of Episode 2. [[spoiler: The rebel's main headquarters comes under attack from multiple directions. Dozens of combine EliteMooks storm through the roof on dropships and set up numerous defensive positions, a bunch of [[LightningBruiser Hunters]] break in to support them, and a dozen striders, each supported by 2-3 Hunters, start attacking the base. After the rebel personnel get completely slaughtered, they just send Freeman, thinking that he's all they'll need to repel hundreds of heavily armed and armored dark energy rifle wielding super soldiers, and a bunch of giant tripod death machines supported by dozens of other, smaller tripod death machines. [[CurbStompBattle They're right.]] [[CrowningMomentofAwesome Completely.]]]]
* SpecsOfAwesome
* TheVoiceless
* WeaponOfChoice: His trademark weapon is a red crowbar he found in a tool kit at Black Mesa.
** Alternatively, he's also depicted wielding a pump-action shotgun.
** From ''Half-Life 2'' onwards, the Gravity Gun.

!!'''Barney Calhoun'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/Clipboard01_7670.png]]

->'''Age:''' Unknown.
->'''Education:''' 2 years Martinson College, Undecided Major.
->'''Employer and Position:''' Black Mesa Research Facility, Security Guard.
->'''Clearance:''' Level 3.
->'''Disaster Response Priorities:''' Preservation of research equipment and materials, welfare of personnel, and personal safety.

->Voice Actor: Mike Shapiro (''Half-Life 2'' and ''Episode One'')

The player character in ''Blue Shift'', Barney Calhoun was a security guard at Black Mesa, and arrived to his duties at the same time as Gordon. Unlike Gordon and Adrian, he was the only player character in the first ''VideoGame/HalfLife1'' not to have an [=HEV=] Suit, and the only main character to escape from Black Mesa on his own, along with a few scientists.

In ''Half-Life 2'', Barney, posing as a Combine Civil Protection security guard, saves Gordon from heading to Nova Prospekt. Helps Gordon in the Resistance movement in City 17, and for ''Episode One'', helps some of the residents evacuate. Last seen boarding a train outbound from City 17 by the end of ''Episode One'' with the help of Gordon and Alyx, his whereabouts are unknown in ''Episode Two''.

* AscendedExtra: From being a stock security guard in ''VideoGame/HalfLife1'' to the star of ''Blue Shift'' to a major character in ''VideoGame/HalfLife2''.
* {{Badass}}
** BadassNormal: Went through ''Blue Shift'' with only security guard equipment.
* CallBack: In ''Half-Life'', Barney invites Dr. Freeman to join him on the firing range and grab a beer with him. In ''Half-Life 2'', he mentions he still owes Freeman a beer.
* TheLancer: Fills the gap for Alyx in ''Half-Life 2'' during the chapter ''Follow Freeman!''
* NiceGuy
* OneManArmy: In "Blue Shift"
* PrecisionFStrike: Gives one at the end of the chapter noted above.
--> '''Barney:''' And if you see Doctor Breen tell him I said "FUCK YOU!"
** Of course, [[SoundEffectBleep it's censored by Dog closing the entrance into the Citadel that you just entered]], but the dialog is intact in the game files.
*** Also, the subtitles censor a different portion of the word "fuck" than is covered by the audible crash.
* PutOnABus: More accurately, the second-to-last train to leave City 17 at the end ''Episode One.''
* ReverseMole: Works within the Civil Protection and uses it as a means to help civilians escape from the city
* RebelLeader: He seems to be the rebels ''de facto'' field commander, behind in rank only to Eli and maybe Gordon.
* TookALevelInBadass: Barney handles himself well in ''Blue Shift'' (even surviving through Xen, for one), but when we meet up with him in the second game, he's one of the leaders of the Resistance, their mole in Civil Protection, and once the revolution hits the streets, a competent field commander.

!!'''Corporal Adrian Shephard'''

[[quoteright:164:http://static.tvtropes.org/pmwiki/pub/images/Adrian_Shephard_8928.png]]

->'''Age:''' 22.
->'''Training:''' United States Marine Corps, Special Forces.
->'''Assignment:''' Hazardous Environment Combat Unit, Santiago, Arizona.
->'''Mission:''' Classified.

The player character in ''Opposing Force'', Adrian Shephard was one of the men in his unit assigned to Black Mesa to do a full containment, cleaning out the witnesses, and finding Gordon Freeman. However, his transport was ambushed and shot down before he was given his mission, which leads him to work together with Black Mesa's scientists and security guards despite them becoming increasingly distrustful of him as the game progresses. In some of his attempts to escape and regroup with any members of his team, the G-Man both helped and hindered him along the way.

He was ultimately detained by the G-Man in AnotherDimension at the end of ''Opposing Force'', now pending further evaluation.

* {{Badass}}: Well, he is a highly trained marine with the best equipment that his unit can provide, but he still is way better at fighting than the other soldiers.
* CoolPet: One of his weapons is a Spore Launcher, which is a small which he uses to shoot at bigger aliens. The reason it is considered a pet is that if the player is standing still long enough while equipping it, Shepherd will actually pet it.
* TheFaceless: Has only two character art pictures of him, both with his gas mask on. His multiplayer image is just a generic HECU soldier.
* FateWorseThanDeath: We don't know much about his detainment, but it's probably like this.
* FingerlessGloves: Yet he [[FridgeLogic wears a gas mask]].
* GiantSquid: This is essentially the final boss that Shepherd kills.
* LongBusTrip: Despite the facts that ''Opposing Force'' ends with Shephard in in a state from which he could easily be brought back, and Gabe Newell himself have stated that Valve is planning to "bring him back one of these days", no mentioning of him has been made in any of the ''Half-Life'' sequels.
* OneManArmy
* WalkingArmory: Notable in that his weapons not only includes various types of guns but also alien lifeforms.
* YouRemindMeOfX: G-Man uses variant 1 towards Shephard, and mentions his ability to survive against all odds as the main reason. G-Man also mentions that this why he saved Shepard's life and argued against his employers' wishes to kill him.

!!'''Gina Cross '''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-gina_cross_416.jpg]]

->'''Age:''' 31.
->'''Employer and Position:''' Black Mesa Research Facility, Research Associate and Hazardous Environment Supervisor.
->'''Education:''' [=PhD=] in Applied Physics, Caltech.
->'''Clearance:''' Level 4.

-> Voice Actor: Kathy Levin

Dr. Gina Cross is one half of the protagonist team in Half-Life: Decay and a Black Mesa scientist. What happened to her after the events of ''Decay'' is unknown.

* ActionGirl
* AscendedExtra: A hologram of her appeared in ''Half Life'' and ''Opposing Forces''. She can also be seen on security camera footage in ''Blue Shift''.
* RedOniBlueOni: The Blue Oni to Green's Red Oni.

!!'''Colette Green'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-colette_green_7665.jpg]]

->'''Age:''' 37.
->'''Employer and Position:''' Black Mesa Research Facility, Research Associate.
->'''Education:''' [=PhD=] in Electrical Engineering, Carnegie Mellon.
->'''Clearance:''' Level 4.

-> Voice Actor: Lani Minella

Dr. Colette Green is one half of the protagonist team in Half-Life: Decay and a Black Mesa scientist. What happened to her after the events of ''Decay'' is unknown.

* ActionGirl
* BloodKnight
* RedOniBlueOni: The Red Oni to Cross' Blue Oni.

[[/folder]]

[[folder: Supporting Characters]]
!!'''Alyx Vance'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/alyxv_1183.png]]

-> Voice Actor: Merle Dandridge (''Half-Life 2'', Episodes ''One'' and ''Two'')

The heroine of ''Half-Life 2'', Alyx Vance helped Gordon Freeman time and again in his work with the Resistance. She also follows Gordon the whole way throughout Episodes ''One'' and ''Two''.

* ActionGirl
* {{Adorkable}}
* AmbiguouslyBrown: See MixedAncestry below.
* ArmorIsUseless: See MadeOfIron; bizarrely enough, she can survive much more damage than other human [=NPCs=] (bar Barney and Freeman himself), even though she's not wearing any kind of armor, just a jacket and hoodie.
* {{Badass}}
** BadassInDistress: [[spoiler:In the initial ''Half-Life 2'', she gets bagged by the Combine during the revolt, and almost ends up sent through a Combine portal before Mossman saves her. In ''Episode Two'', she gets skewered by a Hunter and is rendered OnlyMostlyDead until the Vorts save her.]]
* BoyishShortHair
* ButNotTooBlack: Noticeably fairer-skinned than her father, commonly mistaken for a tanned Caucasian woman (even though she's half African-American, half Malaysian). In discussions praising notable People of Color in video games, she tends to get left off the list as a result.
* DeadpanSnarker
* {{Defictionalization}}: After many years and requests from fans, Valve now sells her Black Mesa hoodie in their online store.
* {{Deuteragonist}}: Of the ''Half-Life 2'' series.
* [[spoiler: DisneyDeath: In ''Half-Life 2: Episode Two'' she gets stabbed in the back by a Hunter, and just manages to say "Gordon... Help...." before she passes out, appearing to be dead. Her condition goes from critically injured to no pulse left just before the Vortigaunts manage to save her.]]
* ExpositionFairy
* FingerlessGloves
* {{Handgun}}: Her main weapon throughout the Half Life 2 series is a seemingly custom made machine pistol she carries around in her jacket.
* TheLancer: To Gordon for the Episodes.
* MasterOfUnlocking
* MadeOfIron: It takes an ungodly amount of punishment to kill her, and unlike Freeman and Shephard, there is no in-game justification for it.
* MessyHair
* MissingMom
* MissionControl: Adopts this role occasionally (such as a couple times in ''Half-Life 2''), though she does a ''lot'' more of accompanying the hero into the field.
* MixedAncestry: She has a black father and a Malaysian mother.
* MyNaymeIs: Al'''y'''x.
* NerdsAreSexy: She's very knowledgeable about science and mechanics. Most of DOG is her work.
* PreAsskickingOneLiner: "Hah! No you don't!" ''[beats the shit out of four armed Metrocops in about five seconds]''
* PrecisionFStrike: She responds to [[spoiler: Mossman's attempts to justify her betrayal]] with "[[ShutUpHannibal Enough of your bullshit!]]"
* RescueIntroduction: She and Gordon meet when she saves him from a group of Metrocops.
-->[[PreAsskickingOneLiner "Hah! No you don't!"]]
* SecondaryFire: Her custom machine pistol is capable of both semi-automatic and automatic fire.
* SpitefulSpit:
-->'''Breen:''' ''[to Eli]'' Will you let your stubborn short-sightedness doom the entire species, or...''[touching Alyx's face]''...will you give your child the chance her mother never had?\\
''She spits in his face.''\\
'''Alyx:''' How dare you even ''mention'' her!
* TraumaCongaLine: Where to start? For the first years of her life, she lives in the dormitories of Black Mesa, a [[NoOSHACompliance dangerous and accident-prone]] research facility. Then, her mother is killed during the Black Mesa Incident. She only survives because [[spoiler:the G-Man]] saves her life, putting her in his debt unknowingly. Fast forward to when she meets Gordon Freeman, leading to events in which her father is captured by the Combine. In the end, when the [[spoiler:dark matter reactor explodes, killing Breen]], she only [[spoiler:survives because the Vortigaunts teleport her out of the wreckage]]. In the beginning of ''Episode Two'', she is [[spoiler:stabbed twice by the long blades of a Hunter and survives, once again, because of the Vortigaunts.]] Finally, after [[spoiler:Eli, Magnusson, and Kleiner launch the rocket and Gordon and Alyx are about to get into a helicopter to save their friend Mossman, a pair of Advisors smash through the building and kill Eli right in front of her.]]
* UnkemptBeauty
* [[WhyDidItHaveToBeSnakes Why Did It Have To Be Hunters?]]
* WrenchWench

!!'''Dr. Eli Vance'''

[[quoteright:206:http://static.tvtropes.org/pmwiki/pub/images/eliv_6086.png]]

-> Voice Actor: Robert Guilliame (''Half-Life 2'', Episodes ''One'' and ''Two'')

A major character in ''Half-Life 2'', Eli Vance is one of the survivors of the Resonance Cascade incident, a lead member of the Resistance, and Alyx's father. Also known to be a Harvard graduate.

* AscendedExtra: Remember that scientist in ''Half-Life 1'' that sent you up for help after the Resonance Cascade and opened the door for you? That's Eli. Made more obvious in [[VideoGame/BlackMesa the Source, Fan-Made Remake]].
* ArtificialLimb: Eli apparently lost his left leg during an [[NoodleIncident incident involving a bullsquid.]] He has a makeshift prosthetic now.
* DeadpanSnarker
* DistressedDude: One of the major goals driving the plot is Alyx's quest to rescue her father, twice.
* [[spoiler:DroppedABridgeOnHim: When he saw Gordon and Alyx off at the end of ''Episode Two'', he was killed by Combine Advisors.]]
* ISeeThemToo: So far, he has been the only character who has acknowledged G-Man aka "our mutual friend"'s existence to Gordon.
* IWantGrandkids: Hey, you can't blame him, considering the Combine's anti-reproduction suppression field in the past years.
* MyGodWhatHaveIDone: The personal cutscene between Gordon and him in ''Episode Two'' pretty much made him admit [[spoiler: he was doing oversight for the test leading up to the Resonance Cascade.]]
-->''"When he came in, I knew I should have aborted that damn test. [[ForWantOfANail But I didn't]]. The whole world went to hell that day."''
* RebelLeader

!!'''[=D0G=]'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/D0G_9829.jpg]]

A walking junkpile that moves like a robotic gorilla, but has an effective mindset of a dog, hence his name. Fiercely loyal to and protective of Alyx, and her friends by extension.

* BerserkButton: Alyx in danger.
* BigFriendlyDog: You play catch with him as part of Alyx's training regime for the gravity gun.
* TheBigGuy
* CurbStompBattle: Him versus any Combine forces short of a Strider. His favored method is to pick up ground vehicles and throw them at the enemy.
* DavidVersusGoliath: [[spoiler: Him versus a Strider.]]
* RobotBuddy
* WhatAPieceOfJunk: Consider him a junky old robot at your own peril if you're a Combine. He ''will'' thrash you.

!!'''Dr. Isaac Kleiner'''

[[quoteright:191:http://static.tvtropes.org/pmwiki/pub/images/isaac_kleiner_3882.png]]

->Voice Actor: Harry S. Robins (''Half-Life 2'', Episodes ''One'' and ''Two'')

A major character in ''Half-Life 2'', Isaac was the man who recommended Gordon Freeman to Black Mesa Research Facility's Civilian Recruitment Division. Also a survivor of the Resonance Cascade incident at Black Mesa. [[RuleOfThree Was also]] Gordon's theoretical physics teacher at the Massachusetts Institute of Technology.

* AbsentMindedProfessor
* AmbiguouslyJewish: Has a Hebrew given name and a German surname, and named his pet headcrab after a Jewish actress.
* {{Adorkable}}
* AscendedExtra: Like Barney, he's a stock scientist from the original game turned into a main character in the sequel.
* BaldOfAwesome
* CrouchingMoronHiddenBadass
* FluffyTamer: He keeps a 'de-beaked' headcrab as a pet. Her name is [[Creator/HedyLamarr Lamarr]].
* NoodleIncident: It has to do something with the cat and the teleporter in his lab. Barney mentions the cat twice.
* PetsHomageName: His "de-beaked" headcrab is named after Creator/HedyLamarr. It's both a bad StealthPun and a ShoutOut to a classic actress--one who helped pioneer early wi-fi and cordless technologies.
* TheSmartGuy

!!'''Dr. Judith Mossman'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-judith_mossman_7678.jpg]]

-> Voice Actor: Creator/MichelleForbes (''Half-Life 2'', ''Episode One'')

The other scientist at Black Mesa East, and is somewhat distrustful of Alyx. Also [[spoiler:played traitor for Wallace Breen]], but after coming back to her senses, she eventually [[spoiler:saves Gordon, Alyx, and Eli from him]] near the end of ''Half-Life 2''. Was last seen with Resistance members tracking down the ''Borealis'', and got ambushed from the Combine before she could finish her message. She is still alive, whereabouts unknown. Her message was found by Gordon and Alyx, who were pursued by the Combine [[spoiler:for the entirety of Episodes ''One'' and ''Two'']] while delivering it to the scientists in White Forest Base. She will be most likely seen again in ''Half-Life 3''.

* BitchInSheepsClothing
* InkSuitActor: Looks quite a lot like Michelle Forbes.
* {{Jerkass}}
** JerkWithAHeartOfGold
* [[spoiler:TheMole: Initially, but pulls a HeelFaceTurn]] later on.
** It's not clear if she's an example of [[spoiler:a FakeDefector]] or [[spoiler:WelcomeBackTraitor]].
* MyGodWhatHaveIDone

!!'''Dr. Arne Magnusson'''

-> Voice Actor: John Aylward (''Episode Two'')

[[quoteright:218:http://static.tvtropes.org/pmwiki/pub/images/arne_magnusson_4769.png]]

The manager of White Forest Base. Has a very distrustful relationship with Isaac Kleiner (well, they fought between each other for grant money). Later revealed to be the owner of a certain microwave casserole in the lounge of the Sector C Personnel Facilities in Black Mesa.

* BrickJoke: Remember the casserole you had the option to blow up in the beginning of the first game? According to canon, that just so happened to be Arne's casserole, and Gordon did in fact blow it up, something Arne still hasn't forgiven.
* InsufferableGenius
* {{Jerkass}}: Specifically created to be this to contrast with Eli and Isaac
** DrJerk
** JerkWithAHeartOfGold
* RememberTheNewGuy

!!'''Father Grigori'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-fathergrigori_1599.jpg]]

-> Voice Actor: Jim French (''Half-Life 2'')

Very little is known about him other than that he's a Russian Orthodox preacher of questionable sanity who has taken it upon himself to clear his "[[ZombieApocalypse flock]]" from Ravenholm.

* {{Badass}}
** BadassBeard
** BadassNormal
** BadassPreacher
** BaldOfAwesome
* CrazySurvivalist: Grigori's the ''nice'' kind.
* EvilLaugh: His laugh is pretty evil sounding, even though he's helping you.
* GoodSamaritan: Grigori is the only NPC in the entire game to help Gordon Freeman without recognizing who he is. He just thinks it's the right thing to do.
* GoodShepherd: While there are few people left in Ravenholm for him to help, he gives Gordon a shotgun, some supplies, and has built several traps that Gordon uses on the zombies. It is implied that Grigori has done the same for other rebels.
* HeroicSacrifice[=/=]HesJustHiding: The devs have stated Grigori will never appear on-screen again, so whether or not he's still alive is up to you.
* MeaningfulName: "Grigori" is a term in Biblical apocrypha for a group angels tasked with watching over humanity as well as the name of [[GrigoriRasputin another famous Russian preacher]] who was [[RasputinianDeath very hard to kill]]
* SanitySlippage: He's obviously insane, although it's implied that he was driven insane by the whole headcrab infestation in Ravenholm.
* WeaponOfChoice: A [[{{BFG}} .357 caliber lever action rifle]] called "[[ICallItVera Annabelle]]".

!!'''Colonel Odessa Cubbage'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-odessa_cubbage_bust_nlo_7629.jpg]]

-> Voice Actor: John Patrick Lowrie (''Half-Life 2'')

A somewhat suspicious and supposedly British Resistance colonel, leading the New Little Odessa base along the coast. He only appears briefly in the 7th chapter of Half-Life 2, granting Gordon a rocket launcher.

* CallBack: After playing out his minor role in Half-Life 2, he disappears from the plot, and there is no mention of him again. Then, late in Episode One, three independent mentions suddenly turns up concerning him, first Alyx sarcastically claiming he is her father, then two rebels coming to the conclusion that he is an idiot, and finally a rebel who reveals that he had taken the credit for Gordon's work, and who turns out to be an admirer of him.
* CowerPower: When the base he has responsibility to lead comes under an attack threatening its very existence, no less, Cubbage sends Freeman to dispatch the gunship, while he safely hides to send a warning to another base, that mysteriously never reaches its destination.
* FakeBrit
** Complete with fake mustache. It's hard to see because of the low texture resolution, but confirmed in ''Raising the Bar''.
* MilesGloriosus: While there is no explicit mentions of his great military exploits, he does by no means seem like someone deserving a colonel title.
** Better yet, a passing comment in Episode 1 reveals that he took the credit for shooting down aforementioned gunship.
* MysteriousPast: The Prima Guide to Half-Life 2 states that virtually nothing is known of Cubbage's past, his name may even be taken from the outpost, the only thing sure is his cowardice.
** If Gordon uses the Combine binoculars overlooking the New Little Odessa, he can be seen talking to the G-Man.
* RebelLeader: Although how significant he is doubtable.
* SmallNameBigEgo: It is staggeringly clear that he believes himself to be one of the great heroes of LaResistance, although he appears to be the only one with this view, apart from one rebel in Episode One speaking somewhat highly of him.

!!'''Griggs and Sheckley'''

[[quoteright:200:http://static.tvtropes.org/pmwiki/pub/images/griggs_and_sheckley_9725.jpg]]

A pair of resistance members in an underground base, they help Freeman defend the base against an army of Antlions to protect the Vortigaunts while they heal Alyx.

* {{Badass}}: Sort of. They are just normal resistance members, but they perform surprisingly well against the army of antlions.
* DeadpanSnarker
* ProperlyParanoid: When Freeman arrives, Griggs thinks it's a bunch of Antlions. Turns out they're not that far behind.
* RedOniBlueOni: Griggs is the red, Sheckley is the blue.
* ThoseTwoGuys: [[WhatCouldHaveBeen They were originally meant to serve as]] [[ExpositionFairy Exposition]] RedShirts, but they were developed into actual characters who survive the battle.


!!'''The G-Man'''

[[quoteright:211:http://static.tvtropes.org/pmwiki/pub/images/gmn_2813.png]]

-> Voice Actor: Mike Shapiro (''Half-Life 1'' and ''2'', Episodes ''One'' and ''Two'')

A strange character, looking like a blend between a government worker and a businessman, who apparently has some limited control over space and time. All we know is that he's been observing the events of the entire ''Half-Life'' series. And that he is possibly not entirely human. He apparently answers to some higher authority which he simply refers to as his "employers". He has, however, on a couple of occasions hinted that he does not necessarily obey these "employers".

* AffablyEvil: We actually don't know how much "evil" he is. But if he is, he's pretty damn proper about it.
* AmbiguouslyEvil: On one hand, his chessmaster antics, creepy dialogue, and mysterious powers make him easy to see as a villain of some sort. Plus, the Vortigaunts seem to oppose him and Eli suggests [[spoiler: he's the one who gave Black Mesa the crystal that caused the resonance cascade in the first Half-Life]]. On the other hand, we know absolutely nothing about who he actually is and what his motivations are, and he ''seems'' to oppose the Combine, who actually ''are'' villains, and he has saved Freeman and Shephard's lives on several occasions.
* AmbiguouslyHuman: He obviously isn't, but we don't know ''what'' he actually is.
* AccentUponTheWrongSyllable: Although sometimes he accents the right syllable just with ''far'' too much emphasis.
* BlueAndOrangeMorality: For whom does he play? No one knows but him.
* CreepyMonotone: He rarely shows emotion.
** OOCIsSeriousBusiness: But when he does show even a ''hint'' of anger in ''Episode One'', it's bone chilling.
* CreepyShadowedUndereyes
* TheChessmaster: Although no one even knows what he is trying to accomplish.
* [[spoiler:ChildrenAreAWaste]]: The G-Man seems to disagree, as he saved [[spoiler:Alyx Vance]] despite objections from his employers, presumably because he anticipated [[spoiler:the role she'd play in the future]]. They didn't want him to, because "[[spoiler:she was a mere child]], and of no practical use to anyone." Well...how about now?
* ConsummateLiar: If the Nihilanth is to be trusted (which is a dubious condition, to be sure).
-->'''Nihilanth''': '''''Deceive you... he will deceive you...'''''
* GracefulLoser: Not ''necessarily'' a villain, but when the Vortigaunts foil some plan he has for Gordon, he is annoyed but doesn't retaliate; he simply waits for another opportunity to make contact, and does not seem to hold any kind of grudge against them for their interference.
* HumanoidAbomination: ''Maybe''. Standing still, he looks human. When he moves and where he appears tells you that he cannot be.
* IcyBlueEyes / CreepyBlueEyes: Look at those eyes. What the hell is up with those eyes.
* InexplicablyAwesome: One of the most intriguing parts of the G-Man is how little we know about ''anything'' about him, including how he does what he does, what he is, who he works for, and what he wants.
* InvisibleToNormals: He can apparently choose which persons are able to see him, and it is hinted that he also has some power over if they remember him or not afterwards.
* ISeeThemToo: The G-Man appears to be invisible to everyone but Freeman and Shepherd at times. However, the Nihilanth, Eli Vance, and the Vortigaunts are all also aware of his existence.
* LackOfEmpathy: Debatable. He saves Gordon's life quite a few times and later [[spoiler: he admits he saved Alyx and her family during the Black Mesa disaster]] suggesting that maybe he's capable of mercy. He also mentions to Shepard that he saved his life specifically because he sees him as a kindred spirit.
* ManipulativeBastard: From locking out Gordon and Adrian from certain doors, to shoving them in deep-freeze, yeah.
* TheMenInBlack: Doesn't quite fit the trope, but sure as hell evokes the basic concept, probably deliberately.
* NobleDemon
* NoNameGiven: While he is called "G-Man" in the credits and character models, he is never actually referred to as this in-story. The only direct reference to him is Eli's label of "our mutual friend." As such, G-Man is not his actual name or even an InSeriesNickname.
* OffscreenTeleportation: Though there are ''two'' scenes where you get to see him do it: Once in ''Half-Life'' ("Lambda Core"), and once in ''Opposing Force'' ("Foxtrot Uniform"). Though he has also appeared to Gordon literally out of thin air ''without'' using a visible portal, so...
* RealityWarper: Can casually stop time and plant subliminal orders into people.
* TheSpook
* TheStoic: Has a very emotionless demeanor, though he occasionally expresses slight amusement, and on one occasion the merest hint of anger.
* SufficientlyAdvancedAliens: As far as we can tell.
* TimeMaster: He seems to be able to stop time for his "employees" at the very least.
* UncannyValley: Invoked intentionally. WordOfGod states that he's to hint at some''thing'' trying to ''look'' [[AFormYouAreComfortableWith human]], but not bothering to try very hard.

[[/folder]]

[[folder: Antagonists]]

!!'''Dr. Wallace Breen'''

[[quoteright:189:http://static.tvtropes.org/pmwiki/pub/images/brn_9315.png]]

-> Voice Actor: Robert Culp (''Half-Life 2'', cameo in ''Episode One'')

Breen is the earlier head of The Black Mesa Research Facility, and was unnamed and unseen in the first game, where he is merely referred to as "The administrator". In ''Half-Life 2'', he is the main antagonist and the Combine's puppet ruler of Earth, a position he got after selling out mankind to them.

* AffablyEvil: Breen's pretty well spoken and (mostly) calm for being a smug backstabber...
** FauxAffablyEvil: ...but he's also cold, dismissive, patronizing, and arrogant. Though he often covers it with a veneer of concern, friendliness, and approachability especially in his Breencasts the underlying disdain and indifference, even towards his allies, is unmistakeable.
* BeardOfEvil
* BigBad: of Half-Life 2.
* BreakingSpeech: He's quite found of these such as near the end of ''[=HL=]2''.
--> '''Breen''': I'd like to take a moment to address you directly, Dr. Freeman. Yes, I'm talking to you. The so-called One Free Man. I have a question for you. How could you have thrown it all away? It staggers the mind. A man of science, with the ability to sway reactionary and fearful minds toward the truth choosing instead to embark on a path of ignorance and decay. Make no mistake, Dr. Freeman. This is not a scientific revolution you have sparked...this is death and finality. You have plunged humanity into freefall. Even if you offered your surrender now, I cannot guarantee that our benefactors would accept it. At the moment, I fear they have begun to look upon even me with suspicion. So much for serving as humanity's representative. Help me win back their trust, Dr. Freeman. Surrender while you still can. Help ensure that humanity's trust in you is not misguided. Do what is right, Dr. Freeman. Serve mankind. ''
* CorruptCorporateExecutive: He was the administrator of Black Mesa before becoming the Combine governor of the Earth, and pushed for the risky analysis that eventually led to the disaster in the first game.
* EvilOverlord: Of City 17.
* TheGhost: In the first game, he's just referred to as "The Administrator" a couple of times.
* {{Hypocrite}}: In his Breencasts he says that "small minds" use the term "the Combine", ostensibly eschewing that label in favor of "Our Benefactors" and "the Universal Union"; but when you meet him in person he calls them "the Combine" himself.
* [[spoiler:KilledOffForReal: As of ''Half-Life 2''. As of Episode 1 he may have become an Advisor.]]
* MisanthropeSupreme: His motivations are a wee bit unclear. He ''did'' convince [[TheJuggernaut The Combine]] to enslave rather than exterminate humanity (and was afterwards named Administrator of Earth), but whether he did so for personal power, or because he really cared about humanity is left unclear.
* {{Narcissist}}: He's got propaganda posters of himself in City 17 and even busts of himself in some locations including ''his own office''. Then there's the fact he's got jumbo screens of himself talking plastered all over the place.
* [[spoiler: NeverFoundTheBody: We never really know what happened to him after the end of ''[=HL=]2'' when The Citadel is destroyed.]]
* NonActionBigBad
* TheQuisling
* SesquipedalianLoquaciousness: Mildly. He's very eloquent and likes to use fancy or obscure synonyms for common words. It's like he reads thesauruses in his spare time.
* SmugSnake: Things escalate beyond his control rather quickly.
* VillainousBreakdown: He becomes increasingly impatient and childish as Gordon Freeman kills off his soldiers and starts a rebellion. When Gordon invades the Citadel, Breen goes from first trying browbeating him into surrendering, to frantically, but still condescendingly trying to reason with him, and finally he starts outright begging for him to stop. Later, while trying to escape via teleport, he resorts to juvenile taunting and mockery.
* WellIntentionedExtremist: Judging by the events of the Seven Hour War, he managed to stave off extinction. It was either Death or AFateWorseThanDeath. He chose the latter. Breen might honestly believe that the Combine will elevate humanity to the next level, though he has turned a blind eye to TranshumanTreachery by the Combine, and his behavior behind closed doors suggests that he may be in this purely for the power.
* WickedCultured: He shows a mild example of SesquipedalianLoquaciousness, and makes reference to advanced physics notions several times, but we're not sure exactly what his MorallyAmbiguousDoctorate is actually ''in''.

!!'''The Combine''', a.k.a. '''The Universal Union'''

[[quoteright:200:http://static.tvtropes.org/pmwiki/pub/images/200px-Combine_svg_4940.png]]

A powerful trans-dimensional alien empire, they conquered the Earth and are the main antagonists in Half Life 2 and its episodes, as well as the whole series, as the Nihilanth was on the run from them. Their occupation force on Earth, the Overwatch, consists of a portion of their transhuman forces (modified humans using human vehicles and weapons), and "Synths", aliens who have been modified and outfitted with cyborg attachments and pulse weaponry.

* AliensAreBastards
* AmbiguousRobots: Synths.
* ArtificialBrilliance: None of the Combine forces are stupid. The Overwatch soldiers will flank, throw grenades, and run to cover when reloading, the Hunters will use splash damage, flank, and lay down suppression fire, and the Gunships will wildly strafe while firing, and will even shoot down your missiles in mid-air. Foot-soldiers, however, do not have a high amount of hit points, and will usually get killed by the player before their strategies can kick in.
* AuthorityEqualsAsskicking: The Combine Advisors are the top tier in the Combine hierarchy, or very close to it; they have the authority to subsume any Combine forces they need, and sacrifice them without a second thought. While they resemble blind limbless grubs the size of baby elephants, they have powerful [[MindOverMatter telekinetic]] and [[MindRape telepathic]] abilities, and are able to completely immobilize and control anyone around them, as well as levitate themselves for transport.
** They are also MadeOfIron. You actually briefly get a chance to shoot at one during the first stage of the assault at White Forest, using a mounted pulse cannon, which seems to be the Combine's equivalent to a .50 machine gun. Desptie taking many shots, only a few of which are enough to kill PoweredArmor wearing cyborgs, the Advisor shows no visible signs of injury and escapes unharmed. This also shows the limits of their powers; the Advisor can't actually throw Freeman around like the previous ones did, only being able to give him a headache, likely because of the (not at all long) distance between them.
* BigBad: Of the second game and subsequent episodes.
** BiggerBad: Of the first game. Also in ''VideoGame/HalfLife2'', while Breen acts as the BigBad, the Advisors are clearly above him and are seemingly the Combine's leaders.
* LesCollaborateurs: The Civil Protection members are humans who willingly decided to work with the Combines.
* CreativeSterility: For all their advanced technology, The Combine Empire appears to be chronically unable to create something that is truly their own, original design. Every bit of their technology and utilities appears to have conceived by violently appropriating an already existing design from another race and then building upon, or rather twisting it until it serves the purpose they need it for.
* DirtyCoward: The Advisors take no issue with personally killing those who can't fight back (thanks to their [[PsychicPowers telekinesis]]) but tend to immediently flee whenever someone has a fighting chance. [[StrawHypocrite This is despite Combine propaganda encouraging every ground troop to fight to the death.]]
* EliteMooks: The Combine Elites
* TheEmpire: Possibly the best example. Most fictional empires would be satisfied with taking over the world or, at most, the galaxy. The Combine instead conquered ''the entire universe''. But then, even ''that'' wasn't enough, so they made portals to other universes and proceeded to conquer them too.
* FakeUltimateMook: The Combine Overwatch may look big and scary, but the untrained rag tag rebels are actually better shots (strangely this only applies to SMG's, rebels and combine soldiers are on par in accuracy with the other weapons). The Overwatch soldiers are actually more effective in combat though because of their ability to throw grenades and their slightly larger amount of health.
* {{Foreshadowing}}: At the very least, something much nastier than the Xenians was hinted at by the Nihilanth way back in the first game.
-->'''Nihilanth''': Their slaves... we are their slaves... we are...
* GasMaskMooks: Justified, in that Overwatch Transhuman troops are in use on other, non-human-habitable planets.
** Apparently the Civil Protection officers just wear them because it looks intimidating. Also Justified; this is something SWAT teams do in real life. Besides, given how brutal the metrocops are, it's probably best they remain faceless and anonymous.
* InsectoidAliens: The land Synths look like insectoids, while aircraft Synths look more like cetaceans or [[GiantEnemyCrab crustaceans]]. Made of metal. [[MoreDakka With guns]].
* InsignificantLittleBluePlanet: It's clear that they don't give two shits about Earth or the humans, considering the token force they've left to occupy it (with the majority of even the transhuman forces being used elsewhere) and the [[CrapsackWorld state of the planet]] after they're done draining it for resources. They've conquered millions of species, the humans are just one more to them.
** On the other hand, once they learn that the Rebels have developed simple and cheap teleportation (compared to the Combine teleporters at least), the Combine becomes immensely more interested in their activities.
* {{Leitmotif}}: [[http://www.youtube.com/watch?v=wWL3kRbArjY "Combine Harvester"]], though sadly not used in the games. It's MusicToInvadePolandTo mixed with haunting alien noises.
* LoadBearingBoss: A collective, in-story version. For all the Combine's cruelty, they at least did manage to keep the massive Antlion infestations in check and keep headcrabs out of their cities. But then Gordon Freeman blew up Nova Prospekt, destroyed their defensive network of machine gun bunkers and 'thumpers' on the coast (thereby letting the Antlions into Nova Prospekt), slaughtered hundreds of soldiers and Synths, started a worldwide rebellion, and blew up the Citadel. All these things caused the Combine to lose control over City 17, resulting in a massive invasion by the nearby Antlion colonies and an infestation of headcrab zombies. By the time Episode One begins, the entire region is caught in a [[MeleeATrois four way struggle]] between the headcrab zombies, the antlion hordes, the Resistance, and the Combine.
* MiniBoss: Gunships and Striders.
* MechaMooks: The Earth Overwatch seems rather understaffed (likely due to most of the transhuman forces being shipped off-world), so make use of units like automated turrets, scanner drones, and manhacks to make up for it.
* MultiversalConqueror: According to WordOfGod, the Combine have already conquered several universes, enslaving their home species and forcibly modifying them for use as Synths. They're in the process of doing the same thing to Earth.
* OrganicTechnology: The Synth units.
* PlanetLooters: It's very clear that the Combine have ''no'' long-term plans for Earth. They're visibly just taking every resource they can use (including the ''oceans'', atmosphere, and some population) and shipping it off-world.
* PoliceBrutality: Civil Protection; some of their terror-mongering acts include beating people for no reason, shooting people after they surrender and lining up innocent people on walls and using them for target practice in true Nazi-Gestapo-meets-Soviet-NKVD style. Think of them as a world-wide example of the StanfordPrisonExperiment.
* PuttingOnTheReich: The Civil Protection and Overwatch uniforms were based on Soviet and Nazi designs. This was more blatant in the original concept art.
* TheSingularity: The Advisors have passed it, a ''very'' long time ago, according to WordOfGod.
* SesquipedalianLoquaciousness: Apparently as part of protocol, the Metrocops, Soldiers and even the [[VoiceWithAnInternetConnection Overwatch]] [[CannedOrdersOverLoudspeaker Announcer]] use medical jargon Newspeak to communicate. Alien intruders are "exogens", zombies are "necrotics", turrets are "sterilizers", soldiers are "stabilization delegates", Freeman, as Anticitizen One, is "malignant" and [[OhCrap contact with him]] is a "staph infection". Troops are also routinely issued orders like "inoculate", "shield", "clamp" and "cauterize".
* SlaveMooks: An entire army of them, most of the Combine soldiers you fight throughout Half Life 2 and its episodes are actually cybernetically modified and enslaved transhumans. Also, the "Striders" "Gunships" "Hunters" "Dropships" and "Synth Scanners" you see in-game are all enslaved aliens or biomachines. It's [[WordOfGod implied]] that there are ''millions'' of enslaved species. The vortigaunts may have been one of them, though they were later found to be enslaved by the Nihilanth. In fact, the Nihilanth's species' role in relation to the Combine is never really explained and neither is Race X's role.
* SufficientlyAdvancedAliens[=/=]TheJuggernaut: They curb-stomped the combined military might of every country on Earth in just seven hours. It took Dr. Breen to convince them not to ''exterminate'' every single human and settle for enslaving us instead.
* SociopathicSoldier: Surprisingly, not the Overwatch. They're just brainwashed slaves. No, the real sociopaths here are in Civil Protection, mentioned above in PoliceBrutality; the corps consists of humans who joined the The Combine's forces willingly, for perks like extra rations and sexual privileges. They appear to be somewhere between SWAT police and low-ranking soldiers. Their tasks are basically to instill fear in every citizen, and to brutally crack down on small resistance pockets. Their technology is notably a bit more primitive, as well. Where the Overwatch and Airwatch use Striders, Gunships and energy weapons, CP units make due with [=APCs=], patrol helicopters and sub-machineguns.
* StarfishAliens: The creatures running the whole thing, called "Advisors", resemble rhino-sized brain-sucking grubs with no eyes, arms, legs or face. The [[WordOfGod developers]] deliberately wanted to invoke the image of a species that passed its [[TheSingularity Singularity]] a ''very'' long time ago. They rely on mechanical arms and eyes for manipulation, and anti-gravity packs for movement. Well, those and their [[GameBreaker near-unstoppable]] [[PsychicPowers telekinetic]] and [[MindRape telepathic]] abilities.
* SuicidalOverconfidence: Part of their official policy. Any Overwatch soldier who fails and lives to report about it will receive "permanent off-world assignment". Their destination is likely not pleasant.
* WeWillWearArmorInTheFuture: Averted with the transhuman Overwatch soldiers, who wear kevlar-like soft armor that resembles modern riot gear with what look likes protective inserts, in contrast to the standard Sci-Fi plate armor with ShouldersOfDoom that most FPS soldier enemies tend to wear.

!!'''Race X'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-race_x_4900.jpg]]

A mysterious alien race from the other dimension, they only appear in ''Opposing Force'', where their invasion is repelled by Adrian Shepard and his men, and is finally ended when the US government nukes Black Mesa. Their main soldiers are "Shock Troopers", but they also have creatures such as a giant worm that shoots lasers and a small, fast poultry-like creature that attacks with scythe-like claws.

* BigBadEnsemble: ''Opposing Force'' reveals that US Black Operations and Race X (led by the Gene Worm) were also largely responsible for the events of the first game. The HECU, on the other hand, [[IDidWhatIHadToDo were just doing whatever they needed to do to stop the invasion and survive the Black Ops onslaught.]]
* EyeScream: The way to defeat the Gene Worm.
* MadeOfIron: The Shock Troopers take about twenty [=MP5=] shots to kill, or just three Desert Eagle shots. That's twice as much as the average human soldier.
* PlanetLooters
* ShockAndAwe: The aptly named "Shock Troopers", who carry a weapon called a "Shock Roach", a parasitic bug that shoots deadly electricity when squeezed. Also, the Voltigores, large creatures which shoots powerful bolts of purple electricity.
* ShroudedInMyth: You don't learn much about them other than that they want to take Earth's resources and that they are hostile to Xenian and US Military forces.
* StarfishAliens: Especially the Gene Worm, a very large creature that shoots acid, and can teleport in "Shock Troopers". The manual for the game implies that the gene worm is several miles long and can suck the resources out of a planet, and that the creature you fight at the end of ''Opposing Force'' is just its head.

!!'''Nihilanth'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-nihilanth_model_6522.jpg]]

The ruler of the Xen aliens and the main antagonist of The first Half Life (and by extension, ''Blue Shift'', ''Decay'' and part of ''Opposing Force''). His race was under severe threat from the Combine, being hunted to near extinction. Some time prior to the first game, he enslaved the Vortigaunts, who were further pursued by the Combine. To escape them, he and the Vortigaunts fled to the border world, Xen, where they set up shop. Still desperate, he used the Resonance Cascade to launch an invasion of Earth, and despite the Black Mesa's scientists' best efforts to plug the rift between the dimensions, he was able to use his psychic powers to force it to stay open. His forces had success with pushing back the HECU, but his invasion was ended when the Black Ops nuked Black Mesa and Gordon Freeman traveled to Xen and killed him, finally closing the hole in the dimensions.

* AmbiguouslyEvil: Mostly because we know so little about him; what we do know casts him in an ambiguous light. On one hand, he did enslave the Vortigaunts and invade Earth, with his forces being quite indiscriminate in their killings. On the other hand, the Black Mesa scientists had repeatedly invaded Xen to take apparently valuable crystals and specimens (including actually sentient soldiers in the Nihilanth's army), and Marc Laidlaw confirmed that the Nihilanth's invasion of Earth was largely an act of desperation, as his kind had been hunted to near extinction by the Combine. He also seems to care somewhat about Xen's ecosystem, given his apparent horror in the telepathic message he sends to Gordon after Gordon kills the headcrab queen ("'''Doooone... what have you dooooone?"), and was the only thing keeping the Combine from invading our universe.
* AttackItsWeakPoint: The only way Freeman can kill the Nihilanth is to fire everything he's got directly into its brain. Even then, it takes quite a bit of damage.
* AuthorityEqualsAsskicking: Just like the Combine Advisors, he leads a large army and has very powerful telekinetic powers, which include the ability to teleport himself and others, telepathy, the ability to shoot extremely powerful balls of lightning, and levitation. His commanders and possible relatives, the "Alien Controllers", also possess these abilities, but to much less powerful degrees.
* BigBad: Of the first game, and by extension, ''Decay'' and ''Blue Shift''.
* BlackEyesOfEvil: His eyes appear plain black, unlike the other sapient Xenians, whose eyes are red. He may not even have eyes, just holes where they should be like the Stalkers, but it's hard to tell.
* BodyHorror: In addition to his general creepy anatomy, he also has what appears to be amputation scars on his chest, slave bracelets, and a mutilated legs that have been burned to vestigial stubs. But Marc Laidlaw denies that this is the result of being captured by the Combine, which is a common fan theory.
* ColorCodedForYourConvenience: His orbs all have distinct roles, and are distinguished by color and shape.
** Blue: Balls of energy that kill anything they come into contact with.
** Green: Teleports whoever it touches.
** Gold: Provides a powerful personal shield that protects him from damage.
* EnergyBall: Can launch dozens of energy balls at a time; they each deal a ton of damage, but they can be (barely) avoided with strafing because Gordon Freeman can [[RoadRunnerPC strafe at over forty miles per hour]].
* EvilSoundsDeep
* FatBastard: His torso looks a little more human-like than the other Xen aliens, making it somewhat noticeable that he looks overweight. This is likely the result of his legs being vestigial, and him floating around everywhere.
* FinalBoss
* FlunkyBoss: One of the more annoying parts about the fight with him. He'll launch a green orb that either teleports you to another room or spawns some vortigaunts or [[GoddamnBats Alien controllers]] in his chamber. The second option isn't so bad, since he only spawns a few at a time, but him teleporting you to another room is very frustrating. In one instance, he'll teleport you to a room with a Gargantua, forcing you to have a boss fight ''in the middle of another boss fight''.
* {{Foreshadowing}}: His telepathic messages have a ton of this in regards to the Combine, the G-Man, Gordon, and possibly Breen and Shepherd.
-->''[[BiggerBad Their slaves...we are their slaves...we are...]]''
-->''Deceive you... he will deceive you...''
-->''[[ISeeThemToo Alone... not you alone... not you alone]]''
-->''You are man... he is not man... for you he waits... for you...''
-->''[[WhatTheHellHero Done.. what have you done...]]''
* InterimVillain: Strange inversion; he's only the villain for the first game, but his defeat leads to the Combine finding Earth.
* LoadBearingBoss: Killing causes him to explode, which knocks Gordon out.
** Also one in-story; his psychic powers were the only thing keeping the portals between the Combine's universes and Xen closed. When he died, the Combine were free to pour through Xen, and then to Earth.
* LargeAndInCharge: The largest alien ever encountered in the series in terms of pure size. Even bigger than the three story tall tentacle monsters.
* LeaningOnTheFourthWall: Much like the G-Man and the Vortigaunts, most of his comments may be just as much about the player as they are about something in-universe, and open to many theories. For example, in the quote below, he is both the last of his kind, possibly the last thing keeping the Combine away from Earth, and the ''last boss''.
* MeaningfulName: WordOfGod says Nihilanth implies Nihilism. The -anth suffix relates to the flower-shape of this head.
* MyBrainIsBig
* PivotalBoss
* PowerFloats
* PsychicPowers: The only psychic seen so far, aside from possibly the G-Man, who can affect things on a planetary scale. He was able to keep open a dimensional rift, telepathically mind control an entire species, and, judging by what happened after he died, was powerful enough to trigger disastrous portal storms all over the Earth, resulting in Xen wildlife killing off most of Earth's native fauna. Compared to that, his personal combat abilities (which are still formidable) seem rather unimpressive.
* PuzzleBoss / DamageSpongeBoss: To actually damage him, you need to find out that he is using the crystals to regenerate his force field and destroy the crystals. After that, his protective orbs won't regenerate, and he can be killed, but it takes quite a bit of damage.
* SayMyName: "'''FREEEEEEEEEEEMAAAAAAAN!'''"
* SingleSpecimenSpecies: Justified, since he's...
** LastOfHisKind Said by the Nihilanth himself just before Gordon enters his chamber:
----> '''Nihilanth:''' '''...THE LAAAAAAST. I AM THE LAAAAAAST. I AM...'''
** The Alien Controllers, however, appear to be genetic crossbreeds between Nihilanth and vortigaunt. So at least in them his species continued to exist.
* ShockAndAwe
* {{Telepathy}}: He broadcasts telepathic messages to Freeman all throughout Xen, and can also use this ability to communicate with other Xen creatures.
* TurnsRed: Inverted. Throughout the battle with him, he will become progressively weaker as he gets injured until he finally just starts firing one ball of lightning at a time at you, as opposed to the dozens he fired before.

!!'''The [=HECU=] (Hazardous Environment Combat Unit)'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-hecu_orig_models_3058.jpg]]

The special forces unit who was sent to Black Mesa to clear up the aliens, it is soon discovered that they are also under orders to silence all the Black Mesa personnel...with bullets. They end up having to pull out, leaving behind dozens of their own troops in the process, while the Black Ops took over the operation.

* ArtificialBrilliance: They were praised as being the first tactically intellegent enemies in video games.
* BadassArmy
* BandOfBrothers: Subverted and played straight. Many soldiers throughout ''Opposing Force'' are shown to care for their squad mates, but the same can not be said for many other members of the unit, particularly the commanders, who abandon several dozen soldiers in their attempt to escape from Black Mesa in blatant violation of the "Never Leave a Man Behind" policy. In fact, two of the soldiers refuse to turn Gordon over to their bosses because they don't want to see him alive after he'd killed so many of their compatriots.
* CavalryBetrayal: You rather quickly find out that they are not at Black Mesa to help the employees and especially not Gordon.
* DrillSergeantNasty: The ''Opposing Force'' training level has one guide you through, quoting FullMetalJacket the whole way.
-->"Texas?! Holy cow! You know what comes from Texas, don't you?!"
* FacelessGoons: The shotgun wielding ones wear balaclavas. However...
** GasMaskMooks: Most of them wear chemical warfare gear, such as gas masks, although the officers wear berets.
* FieryCoverup: Their mission.
* MoralMyopia: Two soldiers that capture Gordon seemed rather outraged at him for killing so many soldiers, even though 100% of those guys were trying to kill Gordon.
* {{Retcon}}: Originally, they were only called "soldiers" or "the military". They received their current name in ''Opposing Force''. In the original ''Half-Life'', their helicopters even had a US Army logo on them.
** Given this, and some other facts (HECU grunts are recognized as marines, land vehicles have Army markings, the F16 is a plane used by the USAF) some fans have theorized that HECU is a multi-branch effort, like SOCOM in real life.
* MoreDakka: Many of their weapons, such as the M249 and Flash missile launcher. Hell, even their standard issue sub machine gun has a 50 round magazine.
* RadioVoice: They spoke this way, and it sounded extremely robotic. May have something to do with most of their EnemyChatter being MadLibsDialogue.
* SemperFi
* SociopathicSoldier: A few of them seem to take joy in killing innocent scientists.
-->"I've killed twelve dumbass scientists, and not one of them fought back! This sucks!
** PunchClockVillain: Most of them, however, just do what their commanders tell them to, as evidenced by various lines throughout ''Half-Life'' and ''Opposing Force''.
--->"[[NotWhatISignedOnFor I didn't sign on for this shit!]] Monsters sure, but civilians? ...Who ordered this operation anyway?"
--->--
--->"Government cover-ups were ''[[NotInMyContract not]]'' [[NotInMyContract in my job description]]!"
* TheEngineer: He gets introduced in ''Opposing Force''. While engineers are meant to fix vehicles, the engineer in ''Opposing Force'' is more useful for just opening locked doors with his blow torch and fighting with his [[HandCannon Desert Eagle.]]
* TheMedic: ''Another'' class introduced in ''Opposing Force''. While he isn't very effective with his Glock 17 handgun, he ''is'' the only thing in the game that can heal your teammates.
* TheBigGuy: Yet another class introduced in ''Opposing Force'' is a tall, muscular soldier toting an M249.
* YouAllLookFamiliar: They had exactly four models in the original game, which just changed the head: the caucasian officer who wore a beret, the normal mook who wore a gas mask, the shotgun using soldier who wore a balaclava and goggles, and the grenade launcher using African-American soldier who wore no hat or mask, and smoked a cigarette. The latter was changed to simply being an African-American version of the officer with a mustache in the HD pack.
* YouHaveOutlivedYourUsefulness: They didn't think that their bosses would stop at killing the ''scientists'' because they saw too much, did they?

!!'''The Black Ops'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/250px-black_ops_all_7309.jpg]]

A very shadowy unit sent to Black Mesa after the [=HECU=] failed their tasks, the Black Ops are there to remove ''everything'' in the facility, including the dozens of [=HECU=] stragglers left behind. [[spoiler: [[NukeEm In any way possible.]] ]] Their purpose is only explained in ''Opposing Force''.

* BadassArmy: See EliteMooks. Also, the fact that they never make noise is pretty impressive when they're being shot constantly.
* BlackHelicopter: They use black [=AH-64=] Apache attack helicopters
* [[spoiler:DeusExNukina: The way they eventually take care of Black Mesa.]]
* DoomTroops: the HECU may be a [[PunchClockVillain diverse]] [[JustFollowingOrders lot]], but these guys are a straight Legion of Terror.
* EliteMooks: In addition to being completely silent, the male black ops they use powerful hand to hand moves at close range, run much faster than the marines, and have a little more health. The female black ops on the other hand prefer to flip and jump around wildly while pelting the player with pistol fire and kung-fu kicks.
* FacelessGoons: They all wear balaclavas, and the female black ops also wear night vision goggles.
* HighlyVisibleNinja
** Unless you play on Hard (at least in the first game), in which case [[spoiler: they have {{InvisibilityCloak}}s]].
* {{Fanservice}}: The Female Black Ops had a very exaggerated breast bounce when they walked, never mind they wear absolutely [[SpyCatsuit skin-tight overalls]].
* {{Ninja}}: They are ninjas in all but name, complete with silent, fast movement and using karate kicks and punches at close range. [[http://images3.wikia.nocookie.net/__cb20090408011434/half-life/en/images/3/36/Black_Ops_all.jpg Even their uniforms]] have a "kabuki stagehand" vibe to them.
* RadioVoice: Averted, even though you only hear them speak once (they're completely silent the rest of the time).
* SociopathicSoldier: Unlike the [=HECU=], played completely straight.
* VanInBlack: Well, M35 ''truck'' in black.

[[/folder]]

[[folder: Alien Species]]

!!'''Vortigaunts'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/vrt_4948.png]]

-> Voice Actor: Lou Gossett Jr. (''Half-Life 2''), Tony Todd (''Episode Two'')

* BadassGrandpa: Think an entire race of Yodas. It's exactly as awesome as it sounds.
** In fact an EasterEgg in ''Half-Life 2'' leads you to one of them who lives like a HermitGuru, known in FanDom as the [[FanNickname All-Knowing Vortigaunt]].
* DeathIsCheap / BrainUploading: Apparently, via the "Vortessence":
--> ''"What seems to you a sacrifice is merely, to us, an oscillation. We do not fear the interval of darkness."''
* FateWorseThanDeath: The All-Knowing Vortigaunt states that Freeman did the enslaved Vortigaunts a favor by killing them.
* HeelRaceTurn: Since the original ''Half-Life''.
* HiveMind: Or at least an entire race somehow connected on a metaphysical level by the Vortessence. Whatever ''that'' is.
* MagicByAnyOtherName: They can shoot lightning, they can charge your suit, they can heal [[spoiler:critically-injured Alyx]], and power generators. And it's all just put down to "the Vortessence"
* NotAlwaysEvil: In the first game, they were typical {{Mooks}} for Gordon Freeman to mindlessly kill. It turns out, they were only fighting you because they were enslaved by the Nihilanth, and they help LaResistance in the second game and its episodes. Whoops.
* OneManArmy: You didn't think that the humans were the only ones with these, did you?
** X-8973 and R-4913, the two Vortigaunts from the Playstation 2 exclusive expansion, ''Half-Life: Decay''. They are noticeably more durable than standard Vortigaunts, have stronger and seemingly more developed electrokinesis, and can regenerate health by damaging enemies. Something of a downplayed example though, as they work as a team and only get to take down twenty or so soldiers in the small bonus chapter in which they appear.
** The three Vortigaunts in ''Episode 2'' who slaughter dozens of antlions, turning what used to be a tough HoldTheLine moment into a glorious CurbStompBattle. The one that accompanies you throughout the mines, nicknamed the Victory Mine Vortigaunt, is probably the best example.
* ShockAndAwe
* SlaveMooks: In the first game, but then Gordon Freeman freed them from control of their alien masters.
* SlaveRace: In the first game.
* SpellMyNameWithAThe: They ''always'' call you and Alyx "The Freeman and the Alyx Vance".
* StarfishAliens: They have at least four eyes. That seem to all be ''the same eye.'' Also, they have three arms, lightning powers, and some sort of HiveMind (that may or may not overlap with the very (vort)essence of the universe).
* StarfishLanguage: Vortigese and the related "flux-shifting" ranges from a 'normal' spoken language to telepathy to a language where two vortigaunts have to talk ''at the same time'' to properly communicate.
* SuperStrength: While it is not as pronounced as the strength of the Grunts, they still have it. The very first time you encounter one, it breaks down a 20mm thick heavy metal door with a few hits, with the door being reduced to pieces.
* TookALevelInBadass: In the first game, they were disposable mooks, slaughtered in droves by Freeman and the soldiers. By Half-Life 2, they're much more powerful combatants (individually about on par with the original's Hard mode Vortigaunts) and have gained new mystical abilities including, at one point, resurrecting someone from the dead.

!!'''Headcrabs'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/headcrabcollection_970.jpg]]

Parasitic alien lifeforms. Originally from an unknown dimension far from Xen, they were eventually brought there by the portal storms. After the Resonance Cascade and the following portal storms, the headcrabs migrated and set up shop on Earth. Their most notable quality is their ability to turn humans (and possibly other creatures) into Zombies by attaching to their heads.

* BodyHorror: For unknown reasons headcrabs mutilate a persons body, possibly because as a parasite they are draining its "resources". Standard Zombies have their ribcages open like teeth and their organs are on display. The bloodied faces of the victims aren't much better.
** It gets worse with elite zombies. Fast Zombies look like all of the flesh save the bare muscle is gone and the poisonouis zombies have a smashed in looking "face" and a back that appears to have been eaten away.
* ButtMonkey: In a way they are this, even if they are creepy. They are usually getting obliterated by both Combine and rebels and even the game actively encourages you to kill them in "creative" ways such as throwing saws, using traps, or setting them on fire. Of the four factions competing for control by the end of Half Life 2 they are probably the weakest, with their only saving grace being their sheer numbers.
* EliteMooks: In the first game, there were just basic headcrabs and zombies. The later games introduce new forms.
** ''Opposing Force'' has the gonome, a mutated version of the standard headcrab zombie. Not only does it have more health than a normal zombie, but it can throw some sort of projectile and sprint.
** ''Half Life 2'' introduces the fast headcrabs and poison headcrabs, as well as their accompanying zombie forms.
* FaceFullOfAlienWingWong: Which causes Barney to refer to them as "head humpers".
* FateWorseThanDeath: Headcrab zombies can be heard crying out in pain, and playing their audio backwards reveals a large amount of dialogue such as "God Help Me! Help me!" or "Get it off me!" This heavily implies that headcrab victims are aware of what's happening but unfortunately there is no way to remove headcrabs [[MercyKill without killing the victim]].
* FragileSpeedster: Fast headcrab zombies are the fastest ones by far, and are arguably the most dangerous for this reason. However, they have no more health than a standard zombie, and so are only a big threat in large numbers.
* TheGoomba: Both the zombies and the headcrabs themselves, with the former being almost a complete non-threat due to their slow speed, low health, and weak attacks, and the latter dying in one or two hits from just about anything and doing next to no damage.
* MascotMook
* PersonalSpaceInvader
* ZergRush: Zombies are fond of this tactic in Ravenholm and City 17, post collapse of the Sector 17 Overwatch.
* ZombieApocalypse: Can cause this if they show up in large numbers. See Ravenholm.

!!'''Antlions'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/antlions_5540.jpg]]

Large, insect like creatures that migrated to Earth following the portal storms. They seem to operate much like many Earth insects, living in extremely large colonies with other antlions. After the events of ''Half Life 2'', the street war between the Combine and the Resistance has caused a breakdown of the Combine defenses, and the antlions have started pouring in to civilized areas.

* BerserkButton: Don't mess with their grubs. Seriously, don't.
* CannonFodder: Antlion soldiers. The most commonly encountered ones by far, they pretty much just charge and attempt to bite/claw whatever is threatening the colony with little regard for personal safety. Good thing they're extremely numerous.
* DefeatEqualsExplosion: Antlion workers explode when they die, shooting acid everywhere.
* EliteMook: Antlion workers, which use their wings to jump around more often, have twice as much health as Antlion soldiers, and spit acid with deadly accuracy.
* EvilVersusEvil: Their presence is quite a help to the Resistance, as it gives the already overstretched Overwatch occupation force something else to shoot at.
* GiantMook: Antlion Guards, which can soak up bullets and grenades like a sponge and punt [=APCs=] with a headbutt.
* MadeOfPlasticine: Antlions are the only enemies in VideoGame/HalfLife2 that can be gibbed.
* InsectoidAliens
* ZergRush

!!'''Barnacles'''

[[quoteright:200:http://static.tvtropes.org/pmwiki/pub/images/barnacle_8478.jpg]]

Large, stationary creatures that wait on the ceiling for prey to wander in range, where upon they grab their prey with their tentacle and pull it up into their mouth.

* ExtremeOmnivore: They'll eat just about anything organic, from humans to antlions to birds. On the other hand, should they pick up something they cannot eat such as wood, they'll chew it a little, get frustrated and spit it out.
* NeckSnap: How they instantly kill non player characters in the second game. Freeman is immune, possibly due to his HEV Suit.
* OneHitKill: If they actually manage to bite you. Fortunately, this is ridiculously easy to avoid, to the point where you'd have to be trying to get eaten to actually get eaten.
* OverlyLongTongue: Weaponized, as they wait for prey to wander into their dangling tongues and drag them up to devour them.

!!'''Alien Grunt'''

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/alien_grunt_6551.png]]

The backbone of the Nihilanth's Xenian army in the first HalfLife. The Grunts are tall, bipedal, muscular creatures with multiple red eyes, backward jointed legs, tube ears, vertical opening mouths, and an arm sticking out of their chest, similar to the Vortigaunts. They make up a large part of the invasion force during the Black Mesa Incident, where the Nihilanth's forces squared off against the HECU.

* BeeBeeGun: Their weapon, the Hivehand, which shoots alien "thornets", which are less like bees, and more like flying, poisonous, heat seeking armor-piercing daggers of death that can find you ''anywhere''
* {{Cyborg}}: Their armor and weapons look like they are surgically grafted on to their bodies, and the Grunts themselves are artificially created in a factory.
* DumbMuscle: The Grunts only appear to be semi-sentient. They can operate weaponry, including their Hivehands and powerful alien laser cannons, and order around Vortigaunts, but not much else.
* EliteMooks: They're much more dangerous than the Vortigaunts/Alien Slaves, the other foot soldier of Xen in the first game, due to their high health, heat seeking projectiles, and armor.
* NoSell: Shooting the armored parts of the Grunts will simply do no damage at all if you shoot them with a pistol, shotgun, assault rifle, or even an uncharged Tau Cannon. Oddly enough (and good for the player), their armor is placed just about everywhere ''but'' the Grunt's torso, the most likely place it is to get shot.
* MultiArmedAndDangerous: Continuing the Xen theme as seen in Vortigaunts and Controllers.
** This isn't all they share; like the Controllers, they also have the Vortigaunts' red eyes, vertical opening mouths, backwards jointed legs, hoofed feet, [[HumanoidAliens bipedal posture, two legs]], and claws (well, on their third arm at least).
* MoreTeethThanTheOsmondFamily
* OrganicTechnology: Their main weapon, the Hivehand, mentioned above, is a textbook case. This trope applies to the Grunts themselves, as they are a....
* ServantRace: Towards the end of the game, you can find a factory run by Vortigaunts, with several barrels on an assembly line. Opening these barrels will reveal Alien Grunts- the implication being that the grunts are a manufactured species. This fits with the bio-technology theme of Xen.
* SuperStrength: In various scripted scenes, they're seen doing things like prying open steel doors with their bare hands, or punching marines through walls.

!!'''Gargantua'''

[[quoteright:200:http://static.tvtropes.org/pmwiki/pub/images/gargantua_1115.png]]

The tanks of the Xen forces. The Gargantua is a twenty foot tall blue creature with an armored shell, two vestigial arms, two functioning arms, and one large eye. Their main arms have pincers that can open to emit jets of blazing heat. They only appear a few times, but you ''will'' remember them.

* AmbiguousRobots: Their seemingly metallic skin and built in weapons makes one wonder. They actually share a few traits with Combine synths.
* {{Cyborg}} Possibly. It does look pretty mechanical. Special mention goes to its built in weapons, glowing machine-looking eye that changes colors, and armored metallic skin.
* DeathFromAbove: How one is taken out in ''Forget About Freeman''; Freeman calls in an air strike on it, and the HECU aircraft, not knowing who sent the signal, are happy to oblige. Cue exploding Garg.
* KillItWithFire: They have flamethrowers built into their arms.
* MadeOfIron: Bullets just bounce harmlessly off their skin. It takes a TON of explosive or electrical damage to actually put them down, more than the actual M1 Abrams tanks in the game. Even more so in the mod[[Videogame/BlackMesa Black Mesa]] (a recreation of ''Half Life 1'' in [=HL=]2's engine), where there is absolutely no conventional way to kill them, even with all the explosives the player can carry; they can only be taken down with scripted sequences.
* MiniBoss: They serve this role whenever they appear in the original Half-Life; they're very tough, and half the time are meant to be taken down in scripted sequences to boot, but don't last as long and aren't as powerful as the actual bosses, of which there were only three (the [[PuzzleBoss Tentacle]], the [[DamageSpongeBoss Gonarch]], and the [[FinalBoss Nihilanth]]).
* NaturalWeapon: They can open their arms to release streams of fire/plasma/something that's powerful enough to actually reduce a human to LudicrousGibs rather than just burn them. They're also fond of simply crushing their enemies, or shooting a weird energy beam by stomping on the ground that can seek out targets and, again, gib them.
* OneSceneWonder: When they appear; they are always solo. Pretty straight forward in ''Opposing Force'' however, where only one total Gargantua appears in the game; stuck in demolation cables on the hydro-electric dam.
* RedEyesTakeWarning
* WalkingTank: Notable because they actually resemble a giant version of the primary Xenian heavy infantry unit, the Alien Grunt. Both are bipedal, both have backwards jointed legs, hoofed feat, red eyes, multiple sharp teeth, and two arms ending in weird hand-less ends that open up. [[http://images2.wikia.nocookie.net/__cb20090328052919/half-life/en/images/thumb/6/6b/Gargantua.jpg/250px-Gargantua.jpg See]] [[http://images.wikia.com/half-life/en/images/7/75/Garg_hand_detail.jpg for]] [[http://images.wikia.com/half-life/en/images/2/23/Alien_Grunt_hd_nohh.jpg yourself.]] This the only real hint we get it in-game that they're part of the Xenian military rather than just wild animals... well, that and the fact that they don't attack sentient Xenians the few times its possible to get Gargs and Vortigaunts in the same room. The same doesn't apply for Xenian wildlife.

!!'''Alien Controller'''

[[quoteright:192:http://static.tvtropes.org/pmwiki/pub/images/alien-controller_7851.png]]

* AirborneMook
* DyingRace: According to Marc Laidlaw, they became either this or just outright extinct after the death of the Nihilanth.
* EnergyBall
* MadeOfIron: Despite being [[SquishyWizard squishy looking]], Controllers can take more damage than even the fully armored HECU soldiers, and much more than the Vortigaunts. This is likely because they have a weaker, invisible version of the Nihilanth's psychic shield, as they share many other abilities with him and do not visually wear any armor.
* MiniMook: They resemble the Nihilanth in many ways, but according to the Nihilanth himself, they're not of the same species. They look like hybrids of Nihilanth and vortigaunt, so maybe they're an artificial crossbreed species.
* MookLieutenant: According to Laidlaw, the Controllers are basically conduits for the Nihilanth's psychic control of the Vortigaunts, and as a result are the highest ranked "generic" aliens on Xen.
* MultiArmedAndDangerous: Just like the Nihilanth, Vortigaunts, and Alien Grunts.
* MyBrainIsBig
* PowerFloats
* PsychicPowers: Similar to the Nihilanth, though much less powerful.
* ShockAndAwe: Via ball lightning, unlike the Vortigaunts' charged beam.

!!'''Alien Aircraft'''

[[quoteright:230:http://static.tvtropes.org/pmwiki/pub/images/alien_aircraft_9639.jpg]]

* AmbiguousRobots: Similar to the Gargantua
* AirborneMook
* DeathFromAbove: Averted; they'll never attack targets on the ground.
* {{BFG}}: The powerful energy weapon they have built into their bellies, which in various scripted sequences is seen doing stuff like disintegrating rather thick rock formations and reducing an Osprey to scrap in less than a second of sustained fire.
* FinalBoss: One is the final boss of ''Decay''.
* FlyingSeafoodSpecial: Hence why they're commonly called "Manta Rays" by fans.
* GentleGiant: When encountered on Xen, they're completely harmless, and are pretty much the only moving thing that WON'T attack you. On Earth, however, they act as a dropship for the Xenian forces and attack HECU aircraft.
* LightningBruiser: Can take as much damage as a tank and fly at speeds that at least exceed Mach 1, evidenced by the shock waves they create.
* MadeOfIron: You only actually fight one once, at the end of ''Decay''. It takes as much damage as a tank to put down, though that may just be its FinalBoss-ness in action.
* NaturalWeapon: A laser-like weapon built into their belly that they can fire downward. It bares some resemblance to the weapon used by Combine Gunships when spawned by the console.
* TeleportersAndTransporters: They appear to have a teleporter built into their bellies, allowing them to drop alien soldiers from Xen.

[[/folder]]
----