This article is about the Milky Way Replicators. For the Pegasus Replicators, see Asuran.
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"We have an enemy in our home galaxy that is far worse than the Goa'uld."

The Replicators are extinct technological life-forms from the Milky Way galaxy and were capable of reproducing themselves indefinitely, consuming all available resources in an area to create more of themselves.



"Don't be afraid. It's just a toy."

Replicator acid spray.

The android Reese created the Replicators as toys to play with.

The Replicators were created at an unspecified time in the past on a Human world where an android called Reese was created. This machine had a childlike personality and was feared by the natives of the planet. In order to keep herself amused, she created the Replicators which were to be her toys. As the population of the world grew more fearful of Reese and the Replicators, she began to teach the machines to protect her and themselves. In order to accomplish this, they began the process of self replication. The Replicators grew too large in number, and Reese herself began to lose the ability to control them. After Reese lost control of the Replicators, they destroyed her world and everyone living on it. The Replicators abandoned Reese in pursuit of raw materials, and Reese, feeling guilty and abandoned, went to sleep. She was later discovered by SG-1 and brought to Earth where she was shot while trying to leave Earth with her newly created Replicators. (SG1: "Menace")

Asgard-Replicator War

"Overconfidence in our technologies has been our undoing. The entities learned from the very means that were employed to stop them. They have become a plague on our galaxy that is annihilating everything in its path."

O'Neill-class ships battle the Replicators

It is not known how the Replicators ended up in the Ida galaxy but the most likely scenario is that the Asgard explored the Human world where the Replicators were first created and brought some of the surviving blocks on board their ship for study, not knowing what they truly are. Once the blocks were brought together, they started replicating and infested the ship and the Asgard were unable to control them. The Replicators then took control of the ship and set course for the Ida galaxy. In a last ditch effort to stop the Replicators from reaching their home world the Asgard destroyed their ship but some blocks managed to survive and reached a planet. Without any further raw materials to replicate they deactivated themselves and waited. At some point, the Asgard explored that planet and uncovered the deactivated Replicator blocks. Since they had no prior knowledge of the Replicators they would have assumed that the Replicators were created in their galaxy and that the creators have been destroyed by the Replicators. During the study of the machines, the Replicator blocks activated and began to assimilate Asgard technology, which allowed them to spread throughout the Asgard's galaxy; given that they had prior knowledge of Asgard technology they would have spread quite quickly and overwhelmed the Asgard. The Replicators then became a plague that destroyed everything in its path. This resulted in the Asgard-Replicator war, which kept the Asgard's attention contained in their own galaxy as they attempted to defeat this robotic menace. (SG1: "Nemesis")

Eventually, the Replicators began taking over Asgard vessels and the Asgard's tactics proved to be ineffective as the Replicators were fast learning machines. This meant that all attempts by the Asgard at defeating them meant that the Replicators simply grew more advanced by learning from the machines that were used against them. As a result, the Replicators began to close on the Asgard planet Othala. In desperation, the Asgard enlisted the aid of the people of Earth to help them combat this threat. With the aid of Major Samantha Carter, which in turn resulted in the destruction of the O'Neill, they were able to stave off this initial invasion of their world. However, this was only a minor victory as the Replicators continued to be a formidable and dangerous foe. (SG1: "Small Victories")

Upon the rediscovery of Reese by SG-1, the Asgard took the android in order to find a weakness in the Replicators. Unfortunately, they were incapable of finding such a critical piece of information. Instead, they hatched upon a plan at containing the Replicator menace. Triggering an activation signal, the entire mechanical horde raced toward the Asgard planet Hala where a Time dilation field was activated which threatened to trap the Replicators indefinitely. However, the Replicators at this point managed to recover Reese and studied her form realizing that there were elements in her makeup that were superior to their own. This in turn led the Replicators to create Human-form Replicators which were composed of microscopic Nanite blocks. The First of these new intelligent Replicators was capable of piercing the Asgard Time dilation device through a microscopic crack and reprogrammed it to serve their needs with the intention of increasing their numbers to such an extent that they would overwhelm the known worlds. However, SG-1 managed to convince Fifth to betray his kin and he activated the Asgard time dilation device though he was betrayed in the process leaving the Replicators trapped frozen in time. (SG1: "Menace", "Unnatural Selection")

Human-form Replicators and Fifth

"To increase our number. That has never changed. And now, thanks to the Asgard, we have all the time in the world. In a few short years, we will go forth as an army."
First speaking of their goals[src]

The Replicators evolve into Human form.

Despite the use of the Time dilation device on the Replicators, it was projected by the Asgard that even is this state, the machines would eventually be capable of deactivating the machine. As such, it was decided that Hala's sun would be collapsed into a black hole by increasing the gravity on its surface. It was believed that a combination of the time dilation field and the growing black hole would destroy the Replicators once and for all. Supreme Commander Thor was dispatched for this duty and he came into contact with Major Samantha Carter and Teal'c from SG-1 who came to ask for his aid. As they waited to see the end of the Replicators, Thor's vessel detected that a branch of the machines had split off from the main group and possessed the time dilation device which they used to counteract the effects of the black hole in a way that even the Asgard were incapable of explaining. As the Replicators were escaping, they came into conflict with Thor's vessel and Carter was abducted by the Replicators after they infiltrated the vessel through a Replicator block made missile that penetrated the Asgard shields.

Carter quickly came to realize that the Replicators were being led by a sole Human-form Replicator, Fifth who had now taken charge of his kin. Due to the betrayal he faced at the hands of SG-1, he held a great deal of anger towards her and plotted to once again increase the Replicators numbers as was originally planned on Hala. To this end, he took his Replicator vessel to the new Asgard homeworld of Orilla where it was destroyed by an Asgard fleet but dozens of Replicator blocks survived and reached the surface of the planet where they began to infest the world thus threatening the stored minds of the Asgard that were waiting for placement into new cloned bodies. Taking hold of the planet, the Replicators began a process of mining Neutronium in order to create new Human-form Replicators and it seemed that the destruction of the Asgard race was imminent.

However, Thor went to Earth and saved the life of Colonel Jack O'Neill who had the knowledge of the Ancients in his mind. Using this information, they managed to construct a weapon capable of destroying the Replicators and something that they were incapable of defending against. Fifth himself came to realize that Carter would never love him and abandoned her on Orilla as well as an unknown number of his kin in order to escape the effects of the Replicator disruptor cannon and fled into hyperspace.

Though defeated, the Replicators were not destroyed and Fifth began to use his stores of Neutronium to create a Replicator copy of Samantha Carter. (SG1: "New Order, Part 1", "New Order, Part 2")

Replicator Carter and Destruction

"You were right about one thing, Colonel. I was never working with Fifth, although he didn't know it."
Replicator Carter[src]

Replicator Carter, the new leader of the Replicators.

After escaping from their near destruction, the Human-form Replicator known as Fifth began to create a duplicate of Lt. Colonel Samantha Carter known as Replicator Carter. This model then apparently escaped to the Milky Way in order to evade Fifth and enlisted the aid of the real Carter stating that she only wanted to live in peace. She claimed that the Replicators had developed a cipher that made them resistant to the Replicator disruptor weaponry. Working together with Replicator Carter, they deciphered what was believed to be a solution as the Replicators were coming to the Milky Way galaxy. When Fifth's vessel arrived in orbit, the weapon was activated by Replicator Carter who destroyed Fifth. After which, she revealed that it had all been a trick as Replicator Carter used Carter to help the Replicators develop an immunity to the disruptor technology. She then escaped through the Stargate and took command of the Replicator armies. (SG1: "New Order, Part 2", "Gemini")

Some time later, the Replicators began their invasion of the Milky Way which began with Replicator Carter's infiltration of the Goa'uld Empire's summit station. The hordes of Replicators began attacking Goa'uld assets throughout the galaxy and began taking over their Ha'tak vessels. One such vessel encountered SG-1 and kidnapped Dr. Daniel Jackson who was placed in a facsimile world by Replicator Carter who disguised herself as Oma Desala in order to gain the knowledge of the Ancients from Jackson. By the time Jackson learned of the deception, it was too late; Replicator Carter discovered a weapon on the planet Dakara that was the only threat to her.

The Dakara superweapon activates

Taking her massive confiscated Ha'tak fleet, she assaulted Dakara which contained elements of SG-1, the Rebel Jaffa and a fleet from the Goa'uld System Lord Ba'al. At the same time, despite protesting that she had no intention of invading Earth to Jackson, the Replicator forces overrode Stargate Command's Stargate and began spilling from it to attack the Cheyenne Mountain complex. In addition, she sent one of her spider ships to Dakara's surface itself which began to assault the Free Jaffa and Tau'ri position there. It was only the intervention and sacrifice of Jackson that helped stall the Replicator forces who were frozen in place temporarily until Replicator Carter regained control of the subspace link. However, by this time, the weapon at Dakara was calibrated which fired a Replicator disruptor wave through a modified Stargate which dialed every planet in the galaxy. The wave disintegrated the Replicators and killed Replicator Carter, though the menace was not over. (SG1: "Reckoning, Part 1", "Reckoning, Part 2")

Rebirth on the Odyssey

"Do you have any idea what it finally took to eradicate these little buggers?"
"Exactly why it'll be so effective in neutralizing the Ori fleet.
James Marrick[src]

In 2007, while in the Alteran Home Galaxy, when SG-1 was searching for the Ark of Truth, James Marrick, under orders of the International Oversight Advisory used the Asgard computer core of the Odyssey to create a Replicator. The Replicator was specially modified by an unknown person who gave the program to Marrick; they were immune to the Anti-Replicator gun, have all of the knowledge of the Odyssey and its systems, and a "self-destruct" built in to them. He told them that it was the IOA's contingency plan, to have the Replicators eventually take over the Ori warships, since they didn't blow up the Supergate. When Lt. Colonel Samantha Carter released the newly created Replicator from the force shield, Lt. Colonel Cameron Mitchell shot it with the ARG, but it has no effect. The Replicator quickly ran away and hid. In hiding, it became a queen and began to repincate. A grouping of these new Replicators eventually broke into Marrick's cell and in an attempt to stop the self-destruct from happening took over his body by sticking their legs into his back and controlling him. Meanwhile, Mitchell located the queen and set up a C-4 charge, waiting for Carter's order to blow the queen to distract the rest of the Replicators before they break into the Asgard core room.

Rebirthed Replicators invading the Odyssey.

While Mitchell was waiting, the Replicator-controlled Marrick arrived and started to fight him. With the Replicators controlling his body, he seemed to have much more strength and resistance to attacks. Mitchell and Marrick fought for some time until at one point when Mitchell pulled one of the Replicator's legs out of Marrick's back. While this was happening, Marrick was released from their control and spoke to Michell telling him of how the Replicators took him to get to the "self-destruct" code which he managed to reveal was on the other side of the crystal used to create them. Right after this, the Replicators retook control over his body, and he resumed attacking Mitchell until eventually Mitchell electrocuted him using a wire on the wall and stumbled out into the hallway while Marrick was stunned. During this time, several soldiers were fighting off a large number of Replicators who were trying to break through to the Asgard computer core. While this was happening, the Odyssey was also under attacked from four Ori warships. Mitchell finally detonated the explosive after he saw Marrick walking out of the room toward him. However, this did not stop the Replicators; from the body's ashes, Replicator blocks arose in the form of a human skeleton and moved toward Mitchell. At the same time, the Replicators began to break through the ceiling of the Asgard core room. Shortly before, Carter retrieved the self-destruct program from the opposite side of the control crystal that Marrick used to create it and activates it. Right as the skeleton Replicator reached Mitchell, it -along with all of the rest of the Replicators- disassembled, finally ending the Replicator threat. (SG1: "The Ark of Truth")


Replicator Blocks

"Each individual building block is capable of exerting a reactive modulating monopolar energy field on other blocks allowing the replicators to assemble themselves into many forms. To our knowledge, the interior of each block contains the following; 2 million isolated keron pathways…"

A Replicator being assembled.

Each Replicator is composed of a series of Replicator blocks. Each block is made up of many Keron pathways. It takes several blocks working together to make new blocks. Replicators are capable of forming many patterns determined by what they need to accomplish. Although Replicators usually take the form of "bugs," they can take other forms. The blocks are capable of absorbing large amounts of energy, which can empower them. The Asgard's dependence on energy weapons made it difficult for them to develop a weapon which could effectively counter the Replicator blocks. Tau'ri firearms were capable of permanently damaging Replicator blocks (at most, it would take two or three shots. although once one was broken to pieces by a rifle but re-assembled itself.) but Human-form Replicators are impervious to them. (SG1: "Nemesis", "Small Victories")

The blocks were either capable of being assembled into the different types of Replicators or were formed into other shapes. They were able to create walls of blocks that served as barricades that prevented the enemy from escaping. Or they were capable of becoming tables and in one case were able to cover an entire planet's surface with blocks which conserved energy. (SG1: "Small Victories", "Unnatural Selection")


"Their capacity for learning is extremely high. Each entity is capable of individual behavior, yet they all act with a common purpose."

Perception from a Replicator's point of view.

Replicators seek out the most advanced technology they can find, and incorporate it into their own being. As a corollary to this, Replicators are often capable of modifying a vessel to perform better than another of its class, to better defend themselves from threats. Both Asgard Bilskirnir-class ships and Goa'uld Ha'taks were upgraded to well beyond the capabilities of their respective races under Replicator control. Generally, Replicators will not attack unless threatened. This behavior will change, however, if there is a Human-form Replicator controlling them.

Each Replicator was capable of independent behavior, but they all were unified in a single purpose which was self replication. They were remarkably adaptive allowing them to develop means at combating strategies that proved effective against them in the past and learn from them. (SG1: "Nemesis", "Small Victories")


"It seems to have permanently disrupted all communication between the individual cells, rendering each one inert."

The only weapon that was capable of destroying all forms of Replicators was the Replicator disruptor produced from the knowledge of the Ancients. This weapon attacked the links that held a Replicator together causing them to fall apart harmlessly. (SG1: "New Order, Part 2")

It was only through the study of the cipher used in the weapon were the Replicators capable of gaining an immunity over it. This allowed them to adapt to varying frequencies of the disruptor after extended use. (SG1: "Gemini", "Reckoning, Part 1", "Reckoning, Part 2")

Before the Replicator disruptor, only firearms were able to destroy replicators. They proved ineffective against Human-form Replicators, which were made up of potentially millions of microscopic blocks.(SG1: "Nemesis", "Unnatural Selection")


"Spider" form

"Spider" Replicators are the basic variation of the Replicator. They are the most seen and most numerous of all the Replicators. The spider Replicators are mainly tasked with moving out and collecting raw materials to bring back to the queen for replication. They try and find the strongest material they can to increase the strength of any newly created Replicators. They are also equipped with a defensive spray that was capable of melting through metals in their path. (SG1: "Nemesis", "Small Victories")

"Beetle" form

Beetle type Replicators with Spider forms on the surface of Orilla.

"Beetle" Replicators were seen on one occasion when the Replicators were attempting to bring a Ha'tak to Sokar's former homeworld and Apophis' new base Delmak. After the ship had reached the planet, SG-1 blew out the crystals of the sublight engine; in retaliation, the giant beetle controlling the engine split apart into multiple spider and beetles. The beetles were larger than the spiders and thus had the ability to jump farther. (SG1: "Enemies")

Several Replicators of this type were sighted on the new Asgard homeworld of Orilla. (SG1: "New Order, Part 2")

"Fly" form

This form somewhat resembles a fly.

Fly Replicators were encountered only once. Though they are around the same size as the spider Replicators, they have shorter limbs, and wing-like structures on their back, making them greatly resemble a fly - hence the name. Despite this, fly Replicators could not fly or jump; instead, they could crawl on walls and fall from short heights such as a table. It is unknown if they could form a queen. Fly Replicators are likely an older model of Replicator, before they 'evolved' into their current state. These were less aggressive than other forms of Replicator, but later became aggressive as they responded to the needs of their maker Reese. The original one, made for Dr. Daniel Jackson to "play" with, was set up in a glass box and remained passive until Reese became emotionally unstable. It then broke out of its glass prison, but was soon destroyed by Teal'c. Reese was locked in a room, where she shut down a surveillance camera and used its parts to make a fly Replicator. That Replicator soon replicated to hundreds of others. This new horde of Replicators were shut down when Daniel convinced Reese to turn them off before she lost control of them; indeed, it was indicated they were beginning to do. (SG1: "Menace")

"Giant Beetle" form

A Giant Beetle Replicator enhancing a Ha'tak's hyperdrive.

"That is a big bug."
Jack O'Neill[src]

A "Giant Beetle" Replicator was seen on the Ha'tak that the Replicators took control of and attempted to head to Apophis' home base. The "Giant Beetle" was at least 100-200 times larger than the a normal spider Replicator. The Replicators formed together into this form as they had reached critical mass and needed more technology to replicate. To do this many individual Replicators formed together into the giant beetle around the engine of the ship. Using their power they managed to speed up the Ha'tak's hyperspeed by over 800 times its normal max. When they arrived at the planet SG-1 quickly destroyed the control crystals of ship. When they did this the giant beetle split apart into a multitude of spiders and normal beetles. (SG1: "Enemies")


Camera shot of an early Replicator Queen.

The Replicator Queen was a unique variant of the Replicator form which was tasked with assembling more Replicators. This task was achieved by having the smaller drones deliver raw material to the queen, which used it to create more drones. The process required large amounts of energy, so a Queen would usually take position near some kind of power source. Every Queen encountered was immobile, requiring the other drones to guard and supply it. (SG1: "Small Victories", "The Ark of Truth")

A much larger Queen.

The first Queen sighted by Stargate Command was present on the Russian submarine Blackbird on Earth around the location of where an Asgard vessel Biliskner crashed. This form was embedded deep within the submarine and was producing more spider-type Replicators. It was destroyed by explosives from SG-1 which attracted the hostility from the remaining Replicators. (SG1: "Small Victories")

A second, much larger Queen was assembled upon the Replicators' resurrection on the Odyssey. This version had tapped directly into the power conduits of the vessel in order to provide the energy to produce more of its numbers. (SG1: "The Ark of Truth")


Main article: Human-form Replicator

Human-form Replicators are Replicators that look like humans. They are composed of millions of tiny nanite cells. They were first created on Hala, after the Replicators discovered Reese. Not much is known about their construction, except that Neutronium is a key element, which was why they invaded Orilla, the Asgard homeworld, as it was rich with Neutronium.

Human-form Replicators are capable of controlling other replicators, and can only be killed with the Replicator disruptor that Colonel Jack O'Neill constructed with the full knowledge of Ancient technology downloaded into his head.


Standard replicator blocks in a Human shape.

Main article: James Marrick

James Marrick was a Tau'ri whose body was taken over by the Replicators in the Alteran Home Galaxy.

A new ability was demonstrated by the Replicators which was the capacity on latching onto the spine of a Human or organic being and inserting a leg into the neck. From that point on, the creature became a puppet used by the spider form Replicator attached to it. It was capable of controlling the body against the will of its host and gave it increased strength as well as an immunity to pain. It was possible for the host to regain temporary control but only if the leg inserted into the neck is removed, however, it was only a matter of time before the Replicator re-asserted its dominance on the body.

After the body was destroyed in an explosion with all its organic components burnt away, the Spider form reconfigured itself, using its Replicator blocks to assemble a skeletal based form. (SG1: "The Ark of Truth")

Known Replicators

Replicator Fleet

The Replicator fleet was a fleet of ships, most commandeered from their enemies, used by the Replicators during their war with the Asgard as well as their invasion of the Milky Way galaxy.

Known ships

Behind the scenes

In Stargate: The Ark of Truth, when Lt. Colonel Samantha Carter is looking at the code for either the Replicators or the shut down function, the code shown on the monitor is actually written in JavaScript. Apparently, it was taken from a real website. The website the JavaScript comes from also presents a sense of irony, due to the Replicator's inherent nature.

The Replicator blocks were both practical (real) props and computer generated images.


  • Although Replicators can repair themselves by re-assembling their nanites, they were only seen repairing themselves once. This was their first appearance in "Nemesis".
  • During the Battle of Dakara, a wave was sent through the Stargate to all other gates in the galaxy, and destroyed all replicators. This means 2 things, the Replicators focused on consuming planets with a Stargate and only controlled a small fleet of ships, all of which were used in the battle.
  • The human-form replicators of the Milky Way galaxy bear a resemblance to the Borg in Star Trek: they are ruled by a queen, seek out the most advanced technologies, adapt to repeated weapons fire, and are in general difficult to combat.

See also

External links