Collector

The Collectors are an enigmatic race that live beyond the Omega 4 Relay, a mass relay within the same system as Omega, in the Terminus Systems. They are rarely seen in the Terminus itself, let alone Citadel space, and are generally regarded as a myth by Citadel citizens. Definite sightings of Collectors have been made on Omega every few centuries.

They are most well known for their odd trade requests for which they offer new technologies, often of a startling level of advancement. Their requests usually involve the trade of living beings in odd numbers and varieties, such as two dozen left-handed salarians, sixteen sets of batarian twins, a krogan born of parents from feuding clans, or two dozen "pure" quarians who have never left the Migrant Fleet due to illness, importance to the fleet, or disability. One of their current interests is in healthy human biotics. No one knows what happens to the individuals concerned after the exchange is completed.

Biology
The Collectors resemble human-sized bipedal insects with a chitinous exoskeleton, two anterior pairs of what appear to be vestigial limbs, four eyes, and a distinct, large, tapering head along with fully developed wings that allow them to fly over short distances. Each Collector appears to be little more than a drone with no distinctions between individuals, although there are witnessed instances of drones towering over humans and their own brethren by a significant margin. Their vocal communication mostly consists of insectoid chirps and trills, although they are capable of speaking in languages other species comprehend should the need arise.

While exploring a supposedly derelict Collector ship, Shepard and team discover the true origin of the Collectors. Since they exhibit a similar quad-strand genetic structure unique to the Protheans, Shepard realizes that the race formerly believed extinct still exists but has been completely subjugated by their Reaper masters. Their DNA showed signs of "extensive genetic rewrite" including three fewer chromosomes, reduced heterochromatin structure, and the elimination of superfluous "junk" sequences.

While studying Collector data in the lab aboard the Normandy SR-2, Mordin Solus determines that the Reapers indoctrinated the Protheans and compensated for their growing lack of ability due to prolonged indoctrination through cybernetic modifications. The modifications are beyond any form of repair, each Collector drone being little more than a clone—it's unknown if they even still possess any form of gender—riddled with cybernetics, lacking glands or digestive system, and having any form of intelligence or self-awareness completely eradicated by indoctrination.

Periodically, individual Collector drones are "possessed" by an overseer, referred to as the Collector General who is itself being possessed by the Reaper known as Harbinger. In effect, Harbinger assumes control of individual Collectors to conduct battles personally. Upon possession, a Collector's skin becomes riddled by red-glowing cracks, and the eyes begin to emit a bright orange glow. Bearing a strong similarity to the husk conversion process used by Sovereign on Saren's corpse, this is probably due to cybernetic implants throughout a Collector's body. At this point, the drone becomes more resilient and wields powerful biotic attacks.

The Collector General differs considerably from a standard Collector, lacking any humanoid traits, with a much larger head, a short body, and multiple claw-like limbs. Collectors in the mold of the Collector General's appearance exist within some of their ships, taking on similar but localized leadership and coordination roles.

Origins
The Collectors arose during the closing years of the Reapers' harvest of the Protheans. The Reapers subjected captured Protheans to extensive genetic experimentation and implanted them with cybernetics. Eventually, the end result was the Collectors, a race of completely subservient creatures that the Reapers could remotely use as tools.

Collectors were deployed against the last Protheans at the end of their cycle. A Prothean plan to place one million of their kind in stasis in bunkers on Eden Prime to wait out the Reapers and then rebuild their empire failed after indoctrinated agents alerted the Reapers. While Reapers razed the Prothean surface cities, Collector Drones infiltrated the bunker system and destroyed hundreds of thousands of occupied stasis pods. In the end, only the Prothean Javik would survive the onslaught.

Once the Reapers concluded their harvest, they departed the galaxy and returned to dark space, while the Collectors retreated beyond the Omega 4 Relay.

Emergence
Thousands of years later, the modern galaxy began to report sightings of the Collectors around 1600 CE, but the mysterious aliens were widely dismissed as myths. All known expeditions to investigate the Collectors failed. No vessel that ventured beyond the Omega 4 Relay ever returned, save those of the Collectors themselves. Some speculated that there was a black hole at the relay's counterpart, but this raised the question of how the Collectors can safely use it. Another more fantastic explanation is that on the other side of the relay was a paradise which no citizen of Omega would care to leave due to the crime and suffering of the asteroid. A more likely reason was that the Collectors either detained or destroyed any vessels encroaching on their space.

The earliest known modern sighting of the Collectors occurred in 2183 CE, less than a month after the Battle of the Citadel. A group of Collectors arrived on the space station Omega to negotiate the purchase of several humans from the Blue Suns. The exchange is interrupted by Aria T'Loak, the Pirate Queen of Omega, and two bodyguards, who proceed to attack the Collectors and Blue Suns. The battle ends with all of the Collectors and human slaves dead, and the few surviving Blue Suns members are rounded up for interrogation and execution. Aria learns from a captured Blue Suns datapad that the Collectors were also interested in the population levels of several major human worlds, foreshadowing the Collectors' master plan.

One week following the incident on Omega, a lone Collector vessel attacks and destroys the SSV Normandy while it was patrolling for geth in the Amada system, located in the same cluster as Omega. Though much of the Normandy's crew escaped, Commander Shepard is lost in the attack and presumed dead. Not long afterward, the Collectors make a deal with the Shadow Broker to recover Shepard's body for an unknown purpose. Shepard's ally Liara T'Soni, with the help of Shadow Broker agent Feron, discover the deal and retrieve the body for Cerberus' Project Lazarus before it can be handed over to the Collectors.

Two years later in 2185, the Collectors reappear as the culprits behind the mysterious mass abductions of human colonies. The Collectors attack their targets without warning, jamming all communications before releasing massive Seeker Swarms: insectoid probes that paralyze everyone in the colony. After that, the Collectors themselves gather all the paralyzed victims, seal them in stasis pods and depart, leaving no evidence of their presence. In the rare instances of heavy resistance and Collector loss they resort to drastic measures of evidence elimination by obliterating harvested settlements from orbit. They also convince the vorcha to release a bio-weapon plague onto Omega that would selectively kill all races on the station except humans and vorcha, leaving its human population ripe for the taking.

At least 12 human colonies are known to have been attacked by the Collectors. The first six colonies were attacked in the time between Commander Shepard's death in 2183 and revival in 2185. The latter six colonies, including Cyrene, Fehl Prime, Ferris Fields, Freedom's Progress, Horizon, and New Canton, are attacked over the course of Shepard's subsequent investigation of the Collectors.

Downfall
As a human-survivalist organization Cerberus was intent on stopping these abductions, especially after realising that there is a Reaper connection to these Collector attacks. The Illusive Man recruits the resurrected Shepard to investigate the purpose behind these abductions.

When Shepard and the team obtain a means to travel safely through the Omega 4 Relay to what is believed to be the location of the Collectors' homeworld near the galactic core, instead, they find the Collector Base, a massive space station. After traversing through many hazardous obstacles and threats, Shepard and the team infiltrate the Collector base where they discover that the Collectors have been processing tens of thousands of humans they have captured, breaking them down and using them to create a Human-Reaper. EDI theorises that the Reapers tried to use Protheans to construct a Reaper, but failed.

Shepard eventually destroys the Human-Reaper and proceeds to set a countdown which would destroy all Collectors on the base. As the Collector General is about to perish, Harbinger condemns the General's failure and states that he is "releasing control," revealing that a Reaper was controlling the Collectors all along.

Concurrent to Shepard's activities in 2185, a separate Collector ship targeted the planet Fehl Prime for its human population. Due to the actions of Lieutenant James Vega the humans were able to obtain valuable intel regarding the race: their origins, their modus operandi, their goals, even their technologies. The intent was to prevent future abductions of human colonies, but it came at the cost of the colony itself and the Collector vessel, and by the time Vega handed over the intel to the Alliance, Shepard had already dealt with the Collector Base itself.

Return
During the Reaper invasion in 2186, the Collectors returned in force. More Collectors emerged from dark space on relatively low-velocity transport ships called Black Arks, allowing them to maintain a low profile while the galaxy focused its attention on the Reapers. It is believed that their arrival was meant to function as deadly reserves, wiping out pockets of resistance while the galaxy's troops engaged the Reapers.

Collector swarms are among the assets the Reapers use against counterattacking turian forces and their krogan allies during the battle for Palaven. Collector forces also play a role in numerous other battles across the galaxy, and deploy Abominations, Praetorians, and Scions in addition to Collector troops.

Not all Collectors remain loyal to the Reapers. The Leviathans, a race with their own enthrallment abilities, are able to sever the Reapers' control of some Collectors. While most of the affected Collectors die, a few survive. These "awakened" Collectors join the rest of the galaxy in the fight against the Reapers to avenge their Prothean ancestors.

Culture
The Collectors themselves are rarely seen since they usually operate through agents, such as the quarian Golo, to make their deals. It has been speculated that the Collectors make these strange requests because of strange fetishes or gruesome culinary tastes, but it is more likely that they perform genetic experiments on these subjects, possibly testing their viability for use in the creation of a Reaper. Regardless of the possible danger, their requests are often granted by fringe groups because the technology the Collectors offer in return is often extremely valuable, giving any race who receives it an immediate advantage before it becomes adapted to the galactic community.

The Collectors are controlled by a single leader who can possess any member of its species at any time, instantly turning them into the most dangerous Collector on the battlefield. When a Collector is possessed by the leader the outer surface of their body appears to crack open, revealing an orange glow that resembles molten rock.

Upon studying the Collectors, Mordin Solus surmised that the Collectors are in fact mindless drones, "closer to husks than slaves" and lacking any form of culture. He observed that the Collectors show no concern for self-preservation, and will die in battle even if their fight is completely pointless. Believing that culture is impossible without intelligence, he hypothesized that the Collector living areas and bases are completely without any kind of art or creativity. All Collector technology and constructions, he said, exist only for their utility without ergonomics taken into account.

Military
In space, Collectors use the Collector Cruiser for transportation of troops and abducted colonists, while Oculus fighters lay in wait in the Tartarus Debris Field for anyone attempting to investigate the Collectors' source. The Collectors were known to possess several such cruisers.

The bulk of Collector forces consist of Collector Drones; depending on their armament and defenses, these Drones have various titles that designate their general roles in combat. Collector ground troops are supported by Seeker Swarms that flood battlefields and paralyze victims. Husks and Abominations provide shock troops, while Scions and Praetorians provide artillery and fire support. Collector operations are personally overseen by the Collector General, who is able to command individual Collectors from the safety of the Collector Base and serves as a conduit for the Reaper Harbinger.

The Collectors do not engage in direct combat, preferring instead to use "hit and run" tactics. A Collector abduction force usually consists of a single Collector Cruiser carrying many troops and Seeker Swarms. They use the swarms to paralyze their enemies and quickly send in light ground forces armed with Collector Assault Rifles and Collector Particle Beams to mop up and take prisoners. When confronted with sufficiently heavy resistance, enough to threaten their ship, the Collectors flee.

Collector troop varieties include:
 * Collector Drone - The standard Collector soldier, equipped with Collector Assault Rifles.
 * Collector Assassin - Equipped with Collector Particle Beams and biotic barriers.
 * Collector Guardian - Equipped with Collector Assault Rifles and biotic barriers, Guardians are also able to deploy personal anti-ballistic shields and use warp ammunition.
 * Harbinger - A Collector possessed by Harbinger is physically transformed and gains armor as well as biotic barriers and powers.
 * Praetorian - Armored constructs fusing Collector DNA with thirty human husks. Equipped with twin particle beams and a powerful biotic barrier. Can be possessed.
 * Collector Trooper - Similar to Collector Drones, appeared in 2186. Equipped with Collector SMGs. Can be possessed.
 * Collector Captain - Collector tactician units, appeared in 2186. Equipped with Collector Assault Rifles and barriers. Can be possessed.
 * Collector Web - Web-like devices deployed by Collector Troopers to restrict enemy movement.
 * Seeker Swarm - Summoned by Collector Captains to harass and disable individual enemy soldiers.
 * Seeker Plague - Enhanced Seeker Swarms summoned by Possessed Captains that can disable whole groups of enemy soldiers.

Trivia

 * The Collectors were originally inspired by electron microscope photographs of insect heads. Their full-body designs ranged from humanoid to highly-abstract creations. An article on the artistic creation of the Collectors can be seen here.
 * The Mass Effect 3: Reckoning DLC pack adds a playable Collector to Mass Effect 3's multiplayer mode called the Awakened Collector Adept.
 * In Mass Effect: Paragon Lost, several Collector Drones seen on the Collector Ship are two or three times larger than normal Collector Drones seen earlier in the movie, and in the games. No explanation is given for these abnormally large Collectors.