Nihilanth

"Truth, you can never know the truth..."

- The Nihilanth

The Nihilanth is the leader of the Xen forces that invade Earth during the Black Mesa Incident, who also acts as the main antagonist and final boss of Half-Life.

Overview
Physically, the Nihilanth resembles a gigantic, abnormally proportioned fetus with a massive head atop a smaller body. The creature's minuscule legs appear either to be vestigial or the remains of amputation, as the Nihilanth relies on a mechanical levitation device for movement.

The head is so large that it must be kept upright with a small cord that extends from the base of the spine to the back of the head. The Nihilanth's body features what appears to be the remains of some sort of surgical procedure and, like the other intelligent Xen races, it has a third appendage protruding from the middle of its pectoral chest region, though it is not known what purpose this serves. Its unusually long arms end in huge hands and disproportionate fingers. The Nihilanth wears metallic wristbands similar to bands worn by enslaved Vortigaunts.

Background
Sometime before the events of Half-Life, the Nihilanth's species came into contact with the Combine. What followed was an incredibly long struggle, that eventually ended with the Nihilanth's kind being hunted to near extinction. The Nihilanth itself was the only survivor, and he and his minions managed to escape into the borderworld, Xen, where they barely managed to survive in a new ecosystem.

Half-Life
Gordon Freeman is tasked with killing the Nihilanth as it is the only force holding the dimensional rift open after the Satellite Delivery Rocket launched by the Black Mesa Lambda Labs failed to reverse the Resonance Cascade. After Gordon enters Xen, the Nihilanth regularly contacts Gordon telepathically and occasionally taunts him. These messages are often received right after a teleportation in Xen.

Upon entering its lair, the Nihilanth attacks Gordon by launching two different types of energy spheres: a swarm of blue-colored electrical orbs which cause immense damage and have a small splash radius and a slow-moving, green-colored orb which homes in and teleports him to other sections of the Nihilanth's lair populated by other Xen aliens. In addition, these green spheres also teleport creatures into the Nihilanth's main chamber on impact with the cavern walls to help defend against intruders.

A series of gold-colored "energy spheres" orbit around the Nihilanth's head, rendering it impervious to damage. These are consumed as the Nihilanth takes damage, but specialized crystals within the upper portion of its chamber replenish the spheres as they vanish. After Gordon destroyed these crystals, the shield put up by the orbs will not regenerate anymore. After a massive amount of damage is done, the shield drops and the orbs disappear, leaving his body exposed and susceptible to damage. At this point, the glow of his brain is visible through his head.

After a large amount of damage is done to the Nihilanth's body (more than it takes to blow up an M1A1 Abrams) the Nihilanth's head opens up like a flower, revealing a shining, vulnerable brain. After a significant amount of damage is done to this, the Nihilanth floats up to the roof of its chamber and dies in a massive green explosion.

Half-Life: Decay
In Decay, Dr. Richard Keller discovers an alien force actively holding the dimensional rift open from the other side, when Dr. Gina Cross and Dr. Colette Green attempt to release the dampening fields to create a resonance reversal after the Resonance Cascade, leading him to realize that not all the aliens are there by accident. This alien force is more than likely the Nihilanth.

Furthermore, in the bonus chapter Xen Attacks, the Nihilanth orders two vortigaunts, drone subjects X-8973 and R-4913, to retrieve several stolen Xen crystals from the Ordinance Storage Facility in Sector E Biodome Complex, a mission the vortigaunts accomplish. This chapter also shows that the Nihilanth is capable of controlling when/where his minions are teleported, and is capable of sending them quite close to their target.

Half-Life 2
In Half-Life 2, the Nihilanth is mentioned by various vortigaunts throughout the game, such as the All-Knowing Vortigaunt, if they are triggered. It is through these messages that it is revealed that the vortigaunts see Gordon as a messianic figure after he frees the vortigaunts, by killing the Nihilanth at the end of Half-Life. This is also the only in-game instances in the series where the Nihilanth's name is mentioned by the characters.

Quotes


There are several cryptic phrases that are either spoken or telepathically broadcast by the Nihilanth once Gordon Freeman reaches Xen, but most are difficult to understand in-game. Below are transcripts of several speech files extracted directly from the Half-Life sound files, note that these transcriptions may not be entirely accurate, as the exact contents of the Nihilanth's speech are fairly difficult to make out due to unclear articulation and the low, gravelly manner in which it speaks. Some of them are not heard at all in-game.


 * "Comes... another...": Said when Gordon first enters Xen.


 * "Win... you cannot win...": Said when Gordon enters "Gonarch's Lair."


 * "Done...what have you done...": Said after the Gonarch's defeat, when Gordon enters the chapter "Interloper."


 * "You are man... he is not man... for you he waits... for you...": Said when Gordon enters the second part of "Interloper" at the alien camp.


 * "Die...you all die...you all die...": Said in the second part of the chapter "Interloper."


 * "Alone... aren't you alone... aren't you alone...": Said in the 3rd map of the chapter "Interloper."


 * "The last...I am the last...": Said when Freeman enters the final part of "Interloper" near an eerie, coral-like altar with a red portal.


 * "Alone... aren't you alone... aren't you alone...": Said when the player is teleported by the Nihilanth's teleport orb for the first time.


 * "Deceive you... will deceive you...": Said when the player is teleported by the Nihilanth's teleport orb for the third time.


 * "Now die... now die... now...": Said during the battle with the Nihilanth, when the player is teleported by the Nihilanth's teleport orb for the fourth time.


 * "Their slaves...we are their slaves...we are..."


 * "The truth...you can never know...the truth..."


 * "Thieves...you all are thieves...you all are...": Heard at the beginning of the bonus chapter "Xen Attacks" in Half-Life: Decay.


 * "The last... you are the last... you are..."


 * "Freeeeemaaaaaannn...": The Nihilanth eerily utters Freeman's name at the very beginning of the game's final battle, indicating that it knows Freeman by name.

Behind the scenes

 * Half-Life 2: Raising the Bar states that the first part of the Nihilanth's name is reference to nihilism (from the Latin nihil, meaning nothing), while -anth is a common suffix that is related to flowers and is a reference to how his scalp peels open like a blossom.


 * Michael Shapiro is uncredited to the Nihilanth's voice. However it can be verified by listening to the Nihilanth's speech sounds and by changing the speed of its grunting sounds.

Trivia

 * Based on some of its speeches and what appear to be surgical scars and amputated legs similar the that of the Stalker's, it is thought the Nihilanth was once a slave to an obscure higher power which was later thought to be the Combine. This theory was dashed by Marc Laidlaw, who confirmed that the Nihilanth had never been captured by the Combine, though some other members of his species might have been.
 * Using the Xen Trampoline scattered around the Nihilanth's lair, it is possible to get into its head. Hitting it with the crowbar shows an interesting blood effect not shown anywhere else, it cannot kill him but it can damage him until his health reduce to 1 point, at that point the player must switch to a firearm and shoot his brain, a single bullet will kill him.
 * Notably, the Nihilanth's head contains a spike that bears some resemblance to the Xen crystals. Laidlaw confirmed that the resemblance was intentional. There is also a corresponding spike on its chamber's ceiling, right above the Nihilanth itself.
 * Using the "notarget" or "god" console command whilst fighting the Nihilanth and later killing him, will result in a continuous loop of his dying animation with no sound and the player being stuck on this stage not teleported to the G-man.
 * Nihilanth is the only Xen creature, aside from the Vortigaunts in Half-Life 2, that can speak English.

List of appearances

 * Half-Life
 * Half-Life 2: Raising the Bar
 * Half-Life: Decay
 * Half-Life 2
 * Half-Life 2: Episode Two