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Xen
General information
Location	N/A
Usage
Era(s)	Black Mesa Incident
Affiliation	Xen
Game information
Map(s)	c4a1 to c5a1 (HL - Xen to Endgame) of3a2 to of6a5 (Op4 - We Are Not Alone to Worlds Collide) of7a0 (Op4 - Conclusion) ba_xen1 to ba_xen6 (BS - Focal Point) ba_outro (BS - Deliverance) ht99alien (HLD - Xen Attacks)
Designer(s)	Brett Johnson[1] (mapping) Karen Laur[2] (textures)

 

Xen (pronounced "zen" ^[3]), or the Borderworld, is a plane of existence connecting two or more dimensions. It was discovered by Black Mesa research scientists, who regularly traveled there via teleportation to collect samples and study the myriad species of flora and fauna within, despite the extremely high risk of doing so.

It is the final retreat of Nihilanth's race, and a place where most of the alien species appearing in the Half-Life series migrated to before coming to Earth during the Resonance Cascade.

OverviewEdit

Rather than being a planet or an artificial structure such as a space station, all of the locations of Xen visited by the player during the course of the Half-Life series are on the surfaces of (or within) asteroid-like "islands" floating within a nebular void.

Xen is notable for having greatly reduced gravity compared to Earth's; however, given that Xen is comprised of low mass asteroids, it is surprising that there is any appreciable gravitational pull at all, let alone a pull strong enough to retain the breathable atmosphere encountered there. It is possible that, given that Xen resides in another dimension or universe, the entire void contains a breathable atmosphere.

Another feature is that gravity is always directed downwards, rather than towards the asteroids, so that one can actually fall off an asteroid into the void below. While it is possible that the "islands" are small chunks orbiting a larger and unseen planetoid, these unusual physics strongly suggest that Xen occupies an alternate dimension where conventional physics may not fully apply.

Light behaves oddly in Xen. Looking at the different skybox textures, there are multiple sources for light in the borderworld, either through glowing clouds of gas or (in some cases) what seems to be a star or some other stellar body.

The exact fate of Xen after the death of the Nihilanth in Half-Life is unknown, though there is a strong possibility that it remains intact. In Half-Life 2, Resistance teleporters are dependent on Xen for intra-dimensional transportation, since the matter stream utilizes the Borderworld as a slingshot to teleport into local space. The G-Man also stated at the end of Half-Life that he and his "employers" are in control of Xen after the defeat of the Nihilanth. While the G-Man says this, dead Marines (the same ones sent to Black Mesa), a destroyed tank, and a downed fighter jet can be seen, implying that American military forces may have participated in capturing Xen, but mostly implies that they've failed at their mission.

EcosystemEdit

The Xen asteroids are home to a wide variety of flora and fauna, forming a complex ecosystem. Although resident in Xen at the time of Half-Life, all of these species originated elsewhere and were forced to flee there to escape attack from their enemies.^[4][5] While mostly seen as lifeless, the presence of water (reddish-green in color) indicates that the dimension is capable of supporting life.

Some species, such as Barnacles, Bullsquid, Headcrabs, and Houndeyes appear to occupy niches similar to various carnivorous terrestrial animals (albeit with unusual anatomical or physiological features). However, even these creatures are dwarfed by the towering six meter high, four-legged invertebrate known as the Gonarch, which appears to be the final stage of a Headcrab's life cycle.

Seen frequently in Xen (and occasionally in Black Mesa, where they transport Alien Grunts), Alien Aircraft glide seemingly without effort through the void. It is uncertain whether these ray-like beings are living creatures or examples of war machines built around advanced biotechnology (such as those used by the Combine). In the closing sequence of Half-Life, and in several areas of Blue Shift, Boids can be seen flying in flocks, emitting resonant calls.

The intelligent species of Xen, such as the Alien Controllers and Vortigaunts, form part of an advanced alien civilization, with species like the Alien Grunts and Gargantua, composing their military. As the player progresses through Half-Life, it becomes clear that this civilization is controlled by a central intelligence, the Nihilanth. Although differing in many ways, the Controllers, Vortigaunts, Grunts, and the Nihilanth share a common morphology that includes a vestigial third limb in the middle of the thorax, suggesting that they are all closely related.

A few creatures that appear in Xen are difficult to categorize as either fauna or flora due to their unusual appearance. Stationary bio-luminescent stalks appear in large numbers throughout Xen and will retract when approached. The much larger and extremely aggressive (but rarely encountered) Tentacles pose a major hazard to those who wander near their pits. There are also bizarre tree-like structures dotted around the landscape, which may be juvenile or even a separate species of tentacle. The "trees" sway gently and appear harmless when observed from a distance, but stab viciously at any creature that enters their immediate vicinity. There are also strange trampoline-like plants seen in Black Mesa and Xen that release a blast of air when stepped on. A similar kind was seen on Xen where it opens and closes, and the opening releases a gust of air like a vent.

Colonization and civilizationEdit

Since the Combine's takeover of the Xen residents' former world, they retreated to Xen via teleportation and colonized Xen with their buildings and technology (also bringing with them invasive wild-life and pests). The buildings for the Vortigaunts were primitive and lacked luxury or necessary needs of survival (besides the healing pool in the back) due to their social class as slaves. The Vortigaunt's buildings look like small hills carved by an unknown tool.

The military castes live in an industrialized, floral Xen Base. The Nihilanth has its own personal chamber which is heavily defended by Vortigaunts, and Alien Controllers.

Behind the scenesEdit

• The "zen" pronunciation of the name is given in Half-Life. First by the "shotgun scientist" met in Level A of the Lambda Reactor Core in the Lambda Complex, then by the G-Man at the end of the game, and by Alyx Vance in Half Life 2 chapter Entanglement.

• "Xen 2" is mentioned as an item cut from Half-Life 2 on a board at Valve's headquarters seen in early 2004. It is unknown if it is related to Xen, or another borderworld like Xen, or a direct or indirect reference to Xen.

• The term "Xen" is seemingly related to the Greek term "Xenos" (ξένος), translated most of the time as "foreigner", "stranger", or "alien". "Xenophobia" is the most common term stemming from it. Furthermore, the WAD file containing the Xen textures (and most of the textures themselves) in the Half-Life game files is named "xeno.wad".

TriviaEdit

• In a brief sequence near the end of Half-Life 2, Doctor Breen can be overheard describing "worlds stretched thin across the membrane where dimensions intersect" or "Gas giants inhabited by vast meteorological intelligences." It is likely that Xen is one of the worlds Breen describes here, or even the "membrane".
• It seems that Xen's atmosphere is not dissimilar to that of Earth's, as the Xen wildlife appears to have no trouble surviving on Earth.
• There is in fact one living scientist in the Nihilanth "side" chambers, he can be found sitting on a small ledge in the room with the Gargantua.
• It is a common misconception that many of the creatures seen in the Half-Life series originate from Xen. This is actually untrue, as all of the Nihilanth's race retreated there in the stead of a Combine invasion on their own planet.
• In the Doom mod Massmouth (as well as its sequel Massmouth 2), there is a chart with a list of names of people and planets they were sent to. One of the rows says "Freeman" and the planet "Xen".

GalleryEdit

Concept artEdit

View of Xen, with two cut creatures, the Flocking Floater and the Kingpin.

View of Xen, with different creatures, notably the cut Stukabat.

Concept art for a map of the Half-Life chapter Interloper.

Concept for the Half-Life chapter Gonarch's Lair.

On XenEdit

Early screenshot.

Bullsquids seen drinking from a pool.

Xen Fungi and a Light Stalk, parts of the Xenian plant-life.

Bullsquid drinking.

Ditto, wide-shot.

Fungi surrounding a pool on an enclosed island.

Mysterious floating islands seen throughout Xen.

Ditto, close-up.

Scientist who came to Xen with another Displacer, clinging to the edge of an island.

Equipment brought to Xen by Black Mesa.

Ditto.

Large Xen crystals making up the Xenian "focal point."

Survey team equipment on Xen.

Ditto, with crystal being studied.

Xen crystals in a crate on Xen.

The "Secret Scientist" that can be found in one of the chambers the Nihilanth can teleport Gordon to.

Xen creaturesEdit

CutEdit

The Archer.

The Charger.

The Chumtoad.

The Fast Walker.

The Flocking Floater.

The Kingpin.

The Mr. Friendly.

The Panther Eye.

The Sand Barnacle.

The Snapbug.

The Stukabat.

Unknown creature / weapon, named "sphere.mdl". It is made of some sort of cannon hidden in a sphere.

RetailEdit

The Alien Aircraft.

The Alien Controller.

The Alien Grunt.

The Barnacle.

The Boid.

The Bullsquid.

The Fungus.

The Gargantua.

The Gonarch.

The Headcrab.

The Houndeye.

The Ichthyosaur.

The Leech.

The Light Stalk.

Nihilanth.

The Protozoan.

The Snark.

The Tentacle.

The Tree.

The Vortigaunt.

Half-Life 2Edit

The Barnacle.

The Beta Bullsquid.

Lamarr, Dr. Kleiner's pet Headcrab.

The Standard Headcrab.

The Fast Headcrab.

The Poison Headcrab.

The Houndeye model from The mod Missing information.

The Ichthyosaur.

The Leech.

The Vortigaunt.

Ditto, Source 2007 version.

Slave Vortigaunt.

Ditto, Source 2007 version.

Uriah's model

List of appearancesEdit

• Half-Life (First appearance)
• Half-Life: Opposing Force
• Half-Life: Blue Shift
• Half-Life: Decay
• Half-Life 2 (Mentioned only)
• Half-Life 2: Raising the Bar
• Source Particle Benchmark (Game files only) (Non-canonical appearance)
• Portal (Game files only) (Non-canonical appearance)
• Half-Life 2: Episode Two (Game files only)

ReferencesEdit

Sector W has more images related to Category:Xen images.