Species
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Major
Asari
Asari Factbox
Homeworld: Thessia
Government: none (independent republics)
Status: Citadel Council
since: 580 BCE
Lifespan: 1,000 years
Form: carbon-based (levo-amino)
Biotics: universal
[Mass Effect Wiki]
The asari are a mono-gendered mammalian biped species with a feminine appearance. They are among the eldest of the modern spacefaring races, having achieved interstellar spaceflight more than 2,500 years ago.
Barring illness or injury, an asari individual can expect to live for 1,000 years. Asari develop slowly, not reaching adulthood until the age of 50 or so.
Asari adulthood is divided into three phases, driven by a mix of socialization and instinct:
- The maiden phase, lasting from onset of adulthood until 350 years of age, is characterized by a drive to explore, meet new people, and form new experiences. The “stereotypical” maiden professions are stripping and mercenary work.
- The matron phase, lasting from 350 to 700 years of age, is accompanied by an expectation that one will settle down, find a mate, and have children.
- The matriarch phase, lasting from 700 until death, is the period in which an asari traditionally serves the community as an honored advisor.
The asari homeworld, Thessia, is laced with element zero; this makes the asari naturally biotic, along with most life on Thessia. Beyond the standard biotic powers seen in other bipedal species, the asari are mildly telepathic, having the ability to link their nervous systems (“meld”) with other asari and even with other intelligent species.
Although mono-gendered, asari reproduction involves two individuals. The “mother” bears the child. The “father” contributes genetic randomization through melding, but no actual DNA, and may be of any species. Asari are naturally exogamous; even before spaceflight, individuals often traveled far from their birthplace to find mates, and in modern times, reproduction between two asari is somewhat rare (and a source of prejudice).
Between their long lives, their telepathic powers, and their exogamous mating practices, the asari have a psychology that discourages risk and conflict, making them natural diplomats compared to the other major species.
The asari have no unified government; instead, Thessia and its colonies are dotted with independently sovereign city-state republics. Most republics are e-democracies: the people directly propose laws and vote on them electronically via the Extranet.
The asari economy is by far the largest and most powerful in the galaxy; this is mostly due to the large number of very old, very well-established colonies in their possession.
Asari military doctrine is to disrupt the enemy through espionage and covert commando operations, thus softening them up for the turians.
Ardat-Yakshi
An Ardat-Yakshi (“Demon of the Night Winds”) is an asari individual born with a serious genetic disorder that causes reproductive melds to be fatal to the partner. The condition is addictive: with each victim killed, the Ardat-Yakshi becomes smarter, stronger, and deadlier.
Salarians
Salarian Factbox
Homeworld: Sur’Kesh
Government: Salarian Union
Status: Citadel Council
since: 500 BCE
Lifespan: 40 years
Form: carbon-based (levo-amino)
Biotics: very rare
[Mass Effect Wiki]
The salarians, a species of warm-blooded amphibian bipeds, are the second eldest of the modern spacefaring races, having achieved interstellar spaceflight not long after the asari did.
Salarians have a very high metabolism, granting them quick thinking and fast reflexes. However, this metabolism comes at the cost of lifespan; salarians reach adulthood at 15 and rarely live past the age of 40.
Salarian sexual genetics is haplo-diploid: unfertilized eggs develop into males, and fertilized eggs develop into females. By social convention, 90% of eggs in a clutch are left unfertilized, and thus males outnumber females 9 to 1. Fertilization is a business contract for salarians: they have no concepts of romantic love or sexual desire.
Mature females, known as dalatrasses, wield great political power: they negotiate shrewd alliances between the matrilineal bloodlines, but are largely focused on internal matters and rarely leave the salarian homeworld, Sur’Kesh. The Salarian Union, their government, is a labyrinthine web of ever-shifting alliances between the dalatrasses.
Few males are ever selected for fertilization, but this leaves them free to develop their own talents. Salarian males are most famous for the twin pursuits of science and military intelligence, and males are largely responsible for diplomacy with parties outside the species (albeit subject to the desires of their dalatrasses).
Salarian military doctrine is to stop a war before it starts, using superior facts to bolster negotiating positions and to assassinate key enemy personnel.
Turians
Turian Factbox
Homeworld: Palaven
Government: Turian Hierarchy
Status: Citadel Council
since: 900 CE
Lifespan: 150 years
Form: carbon-based (dextro-amino)
Biotics: uncommon
[Mass Effect Wiki]
The turians are a bipedal species with a metallic carapace, mandibles, and a smattering of avian features. They joined the galactic community relatively recently, about 1,300 years ago. However, they have been active spacefarers for much longer: they had already established a number of colonies at the same time that the asari were discovering the Citadel.
Turians share many features with humans: they live to be approximately 150 years old, they are viviparous (giving birth to live young), and they have two principal sexes with slight dimorphism (turian men have a crest of horns that turian women lack). However, Palaven, the turian homeworld, has a weaker magnetic field than Earth or most homeworlds, affording the turians less protection from solar radiation. Their metallic carapace helps to shield them against this radiation. Palaven is also one of the few worlds in the galaxy where life evolved to use dextro-amino acids in their proteins instead of the more common levo-amino chirality.
Turian society is heavily regimented and conformist, with the good of the group held above that of the individual. There is no true distinction between civilian and military for turians: citizenship in the Turian Hierarchy is granted through military service, although “military service” includes every civic role from waste technician to primarch. Promotion is through merit; to be promoted above one's skill is seen not as a failing of the individual, but as a failing of those who misjudged that individual's merit.
As befits their society, the turians hold the galaxy's largest standing military. Although militaristic, they are not particularly expansionist or violent: their military forms the bulk of the Citadel peacekeeping force, and turians form the backbone of C-Sec (the Citadel police force).
Turian military doctrine is to identify weak points, attack with overwhelming force, and repeat. Unlike the asari or salarians, the turians do not shy away from a stand-up fight, and they will fight to the last man or woman to defend their ground.
Humans
Human Factbox
Homeworld: Earth
Government: Systems Alliance
Status: Citadel Council
since: 2183 CE
Lifespan: 150 years
Form: carbon-based (levo-amino)
Biotics: uncommon
[Mass Effect Wiki]
Humans are newcomers on the galactic scene, having made first contact only 30 years ago (as of the end of ME3). However, they have rapidly integrated themselves into the galactic community, making huge economic strides and establishing themselves as a major military power.
With gene therapy and other modern medical technologies, humans can expect to live to be 150 years old. In the context of the Mass Effect universe, humans hold the distinction of being highly genetically diverse, much more so than any other sapient organic species. This makes humans less predictable in general, for good or ill.
(Real Life Note: humans are actually among the least diverse species on Earth!)
The bulk of humanity falls under the Systems Alliance, a supranational parliamentary government. Earth's nations still exist, and retain their individual sovereignty; however, the Alliance represents humanity in colonial and interspecies affairs.
Humans are looked at with a mix of curiosity, respect, scorn, and fear. Some admire humanity for coming so far so quickly, but others see humans as ambitious, selfish, power-hungry, greedy, imperialist expansionists. And it's not lost on anyone that the Alliance's military might already rivals that of the turians, despite being an all-volunteer force consisting of 3% of the human population. Whispers of “sleeping giant” are common.
Alliance military doctrine is to harass enemy supply lines with hit-and-run tactics: hit hard, hit fast, and leave before the enemy can regroup. In defensive actions, the motto is Sun Tzu's dictum, “He who tries to defend everything defends nothing”: standing defenses are few, and the mobility of human offensive power becomes the primary form of defense.
Reapers
Reaper Factbox
Homeworld: N/A
Government: unknown
Status: Reapers
since: X billions of years ago
Lifespan: immortal
Form: synthetic-organic hybrid
Biotics: varies by type
[Mass Effect Wiki]
The Reapers are a race of immortal sentient starships. Their bodies are machines infused with organic components. Their minds are vast AIs that contain the memories and knowledge uploaded from millions of organic minds.
Every 50,000 years, they awake from their slumber in the space between galaxies to harvest all advanced life in the Milky Way. Why they do this is a mystery, partially resolved by the ending of ME3 and by the Leviathan DLC.
Few know it, but the Reapers are actually responsible for creating the Citadel, the mass relays, and FTL drive core technology. After each cycle of destruction, they remove evidence of their own hand in galactic affairs, but they deliberately leave behind traces of their technology so that the next generation of species can reach spacefaring status as soon as possible. This reduces the time between cycles, as the species of each cycle become sufficiently advanced more quickly, thus speeding the Harvest.
Reapers come in a number of common sizes:
- Sovereign-class Reapers are 2000m tall sentient dreadnoughts
- Destroyer-class Reapers are 160m tall sentient frigates
- Reaper troop transports are intermediate in size, and are not sentient
- Reaper processing ships are probably the same size as a Destroyer-class Reaper, and are not sentient
- Reaper ground troops are of the same dimensions as the species (s. or pl.) that comprise them
- Husks are Reapers derived from a single human
- Cannibals are Reapers derived from a batarian (body) and a human (body refashioned as an arm)
- Marauders are Reapers derived from a single turian
- Brutes are Reapers derived from a krogan (body) and a turian (head)
- Ravagers are Reapers derived from a single rachni adult
- Banshees are Reapers derived from a single asari
- Harvesters are Reapers derived from an 8m-tall non-sapient flying insectoid species of the same name
- Abominations are Collector-variant Reapers derived from a single human, capable of exploding
- Scions are Collector-variant Reapers derived from three humans
- Praetorians are Collector-variant Reapers derived from thirty humans
- Collectors are Reapers derived from a single Prothean
- “Husk” is also the generic name for any Reaper ground troop
Reapers reproduce by way of the Harvest. Millions, perhaps billions, of individuals of a single species are collected and processed to produce a single Sovereign-class ship.
Sentient Reapers, plus certain specialized Reaper artifacts, are capable of a technological feat known as indoctrination. This allows them to corrupt the minds of organic life forms, bending them to serve Reaper purposes.
Minor
Krogan
Krogan Factbox
Homeworld: Tuchanka
Government: none (tribal)
Status: independent
since: 800 CE
Lifespan: 1,000+ years
Form: carbon-based (levo-amino)
Biotics: rare
[Mass Effect Wiki]
The krogan are a bipedal reptilian species from the planet Tuchanka. They did not come upon spaceflight themselves; they were culturally and technologically uplifted by the salarians some 2,500 years ago.
Krogan are among the longest-lived beings in the galaxy, with a lifespan of 1,000 years… assuming that combat doesn't claim them first. Tuchanka is a harsh homeworld: its wildlife claims the lives of many krogan, young and old, and inter-clan warfare claims much of the rest.
In their primitive state, the krogan were once among the most fecund species in the galaxy, producing about one thousand eggs per year — a necessary counter-balance to their high mortality rate. However, their reproductive rates as of the Mass Effect trilogy timeframe are considerably lower due to the genophage.
When the krogan were first uplifted by the salarians, they were immediately conscripted to serve in the then-ongoing war against the rachni. The krogan, with their prodigious numbers and redundant biology, were able to meet the rachni on equal footing, turning the Rachni War from a desperate fight to preserve Citadel Space to a curb-stomp battle ending with the (supposed) extinction of the rachni.
In exchange for their service during the Rachni War, the krogan were granted pristine colony worlds and allowed to populate them. Within a single millenium, the krogan were suffering from severe overpopulation and demanded more colony worlds; when the Council refused, the Krogan Rebellions began.
The Rebellions ended with the one-two punch of the turians joining the war and the creation of the genophage: the genophage sapped the krogan of their ability to field an effectively limitless supply of soldiers, and the turians had a sufficiently militaristic bent that krogan intimidation tactics backfired and made the turians fight harder.
Krogan politics largely consists of warfare between clans of related males, with fertile females fought over as prized possessions. If Commander Shepard kept Urdnot Wrex alive in ME1, this is slowly changing: under Wrex's the influence, Clan Urdnot is reaching out to the other clans with diplomacy, and is involving krogan women in the decision-making process. In particular, if Urdnot Bakara a.k.a. “Eve” survives ME3, then she is seen by many as a key moderating influence on the krogan.
Quarians
Quarian Factbox
Homeworld: Migrant Fleet (formerly Rannoch)
Government: Quarian Admiralty Board
Status: independent
since: 1895 CE
Lifespan: 150 years
Form: carbon-based (dextro-amino)
Biotics: extremely rare
[Mass Effect Wiki]
The quarians are a mammalian biped species native to the planet Rannoch, a hot desert world located at the tip of the Perseus spiral arm, and one of the few planets in the galaxy where life developed to favor dextro-amino acids in their proteins instead of the more common levo-amino chirality. As of 2186, they live exiled from their homeworld aboard the Quarian Flotilla, a patchwork fleet of ships carrying 17 million quarians and enough of an ecosystem to feed them. The Flotilla travels between star systems, always seeking resources and raw materials to sustain the fleet. The surviving quarians have a single common language, Khelish.
Quarian lifespan is approximately 150 years, similar to that of humans. However, the quarians have a unique symbiotic relationship with the plants of their world: Rannoch is devoid of insect life, and the quarians themselves evolved to be their world’s pollinators. As foreign material embedded in the skin is thus the norm for the quarians, not the exception, their immune systems are thus very weak compared to those of other sapient species. As such, the exiled quarians must wear environmental suits at all times, and every minor suit rupture puts them at serious risk of infection.
The quarians have also developed a very close relationship to their technology, with significant cybernetic enhancements added to their bodies. This may have further weakened their immune systems.
Quarian culture is very community-oriented, as befits their lifestyle in exile. Technically still under martial law since the days of the geth rebellion, matters of the Fleet are determined by the Conclave (an elected body) with the possibility of override by the Admiralty Board (a board of the 5 most senior or well-respected admirals in the military). Matters of individual ships fall under the absolute jurisdiction of the ship's Captain, although most Captains choose to maintain an advisory board of their own.
Quarians possess given names, family names, and one or two ship names. Quarians who have not yet gone on pilgrimage are known by the ship of their birth: for example, “Tali’Zorah nar Rayya” indicates that Tali of the Zorah family was born on the Rayya. Adult quarians are also known by the name of the ship by which they were accepted as adults: for example, “Tali’Zorah vas Neema”, or most formally “Tali’Zorah vas Neema nar Rayya”, indicates that Tali was accepted by the Captain of the Neema after her pilgrimage.
The quarians are notable for having created the geth, a race of machine servants that rebelled 300 years ago and exiled the quarians from their homeworld. The geth were originally intended to be non-self-aware servants, but their networking capability pushed them over the edge. To hear the quarians tell it, the geth uprising was brutal and inevitable.
During the course of ME3, Commander Shepard may tip the quarian/geth conflict to support one side in the extermination of the other, or may resolve the conflict peacefully if certain conditions are met.
Geth
Geth Factbox
Homeworld: Rannoch
Government: consensus
Status: independent
since: 1895 CE
Lifespan: immortal
Form: synthetic
Biotics: none
[Mass Effect Wiki]
The geth are a race of Artificial Intelligences which inhabit Rannoch and the systems near it. The geth were created by the quarians to be non-self-aware servants, but the geth exhibit networked intelligence: as the number of connected geth increases, the geth offload more basic functions and become capable of higher thought. When the geth reached a critical mass, they developed self-awareness and began to ask philosophical questions of their creators. To hear the geth tell it, the geth uprising was a tragic necessity, brought about when the bulk of the quarians panicked and began to exterminate both geth and geth-sympathetic quarians, and ending when the quarians fled and the geth chose not to pursue.
A single geth “platform” (body) houses many individual geth programs, typically about 100. Geth programs share data and perspectives at a speed far surpassing what an organic mind can achieve, achieving total consensus with all nearby geth to make all higher-level decisions. Geth do not have a government, only consensus. Geth programs, while self-aware, do not have “identities” or “individuality”; this in particular makes communication between geth and other sapients confusing.
ME2 reveals that there are two factions of geth: the “true” geth, which are merely isolationists, and the “heretic” geth, which worship the Reapers as gods. The heretics peacefully broke away from the rest of the geth when the geth could not reach consensus on the Reapers. (This may have been due to the Reapers meddling with the heretics.)
In ME2, Shepard encounters a geth platform dubbed “Legion”. This platform, which contains 1,183 geth programs (roughly 10x the usual number), was created to operate independently in organic space as a remote set of eyes and ears for the geth. During Legion’s loyalty mission, Shepard must choose whether to destroy the heretic geth or to rewrite them to rejoin the true geth.
In ME3, Shepard encounters Legion again (if they were recruited in ME2 and survived it). The quarians began a new war against the geth to retake Rannoch, and while the heretics were (possibly) eliminated in ME2, this war forced the geth to ally with the Reapers for their own survival. The geth have been reprogrammed by the Reapers, and the geth comprising Legion are the only geth not being mind-controlled by the Reapers. Legion and the quarians team up with Shepard to take out the Reapers on Rannoch, but Legion reveals that they have separated the Reaper processing upgrades from the Reaper mind control, and they wish to share these processing upgrades with all surviving geth. These upgrades would grant all geth platforms the power to operate as independent, intelligent agents; as a side effect, the upgrades also give the geth programs a collective sense of identity (one identity per platform). If you side with Legion or if you negotiate a peaceful end to the war, then Legion becomes an individual just before it sacrifices itself to disseminate these upgrades.
Volus
Volus Factbox
Homeworld: Irune
Government: Vol Protectorate
Status: Citadel associate
(turian client race)
since: 900 CE
Lifespan: unknown
Form: ammonia-based
Biotics: unknown (prob. uncommon)
[Mass Effect Wiki]
The volus are a diminutive, vaguely humanoid biped species. The volus homeworld Irune has an atmospheric pressure some 60 times that of Earth's, and life there is based on ammonia; therefore the volus must wear pressurized environmental suits whenever they leave their homeworld. Due to the suits, little else is known to outsiders about their appearance and physiology.
Volus culture is tribal and ever-shifting, as clans negotiate deals to trade land, resources, and even other tribe members (with their consent). Volus have no love of war, and see violence as a failure to negotiate properly. Between this and their physical weakness, volus are perceived as pacifistic and somewhat cowardly by other species. Their government, the Vol Protectorate, has been a client state of the Turian Hierarchy since shortly after the turians joined the Citadel Council around 900 CE; they willingly pay taxes to the turians, and in turn they rely on the turian military for protection and are citizens in the Turian Hierarchy. However, they have been active in Citadel Space for far longer, going back to at least 200 BCE when they first established their Citadel embassy.
While few volus leave the comfort of their homeworld, they are nonetheless vital to the galactic economy: the volus established the standard galactic currency (the credit), wrote the laws on interstellar commerce, and constantly monitor and balance interstellar trade.
Elcor
Elcor Factbox
Homeworld: Dekuuna
Government: Courts of Dekuuna
Status: Citadel associate
since: unknown
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown
[Mass Effect Wiki]
The elcor are a large, knuckle-walking quadrupedal species native to Dekuuna, a high-gravity world. While immensely strong, their movements are slow and deliberate — a consequence of evolving on a planet where a fall can be lethal.
Elcor society is organized into small, tight-knit groups (most commonly kin) that travel together. In prehistoric times, elcor were migratory, following the annual wet and dry seasons. Despite being obsoleted by technology, this history is still culturally observed: Dekuuna has two capitols, one for each season. Elcor greatly prefer the open sky over confined spaces, and are thus are proportionally less common aboard spaceships and space stations than most other species.
Instead of using intonation to carry emotional content, elcor possess an impressive array of non-verbal communication to accompany each verbal utterance: a bouquet of pheromones, slight body movements, and subvocalized infrasound. Because other species are not privy to this subtle communication, elcor habitually prefix each statement with the emotion being conveyed when speaking to aliens.
Elcor are deeply cautious and conservative: they almost infallibly follow the recommendations of their Elders, who spend years poring over ancient documents and jurisprudence to determine which precedent to follow for a given situation. They think slowly and deliberately, and they plan for the long term. Elcor space is self-sufficient; they trade only in finished goods, preferring to support themselves rather than rely on the galactic economy. With all that said, however, they are warm and welcoming to strangers.
To make up for their slow and deliberate thinking, in war elcor make heavy use of combat VIs which have been pre-programmed with thousands of carefully selected gambits. They do not make use of small arms; instead, they use their bodies as living weapons platforms.
Hanar
Hanar Factbox
Homeworld: Kahje
Government: Illuminated Primacy
Status: Citadel associate
since: unknown
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown
[Mass Effect Wiki]
The hanar are an aquatic species with an appearance not unlike a 2m-tall Earth jellyfish with prehensile tentacles. They communicate via bioluminescence, relying on software to translate their own language into the spoken languages of other species and vice versa.
Hanar culture places high importance on politeness and decorum. Each hanar has two names: a “face name”, which strangers may know and use; and a “soul name”, which is known only to family and close friends. Hanar do not use the first or second person in polite company; instead, a hanar refers to itself as “this one” and to its conversation partner as “the other”. Hanar consider the cavalier use of the first and second person to be unspeakably rude, to the extent that hanar who leave their homeworld, Kahje, must take classes to desensitize themselves to the (perceived) rudeness of alien speech.
Drell
Drell Factbox
Homeworld: Kahje (formerly Rakhana)
Government: N/A (hanar client race)
Status: Citadel associate
(hanar client race)
since: 1980 CE
Lifespan: 85 years
Form: carbon-based (levo-amino)
Biotics: unknown (prob. uncommon)
[Mass Effect Wiki]
The drell are a desert-dwelling reptilian bipedal species, technologically uplifted by the hanar. Native to the planet Rakhana, their homeworld was dying due to overpopulation when the hanar discovered them, rescuing some 375,000 of them before their ecosystem collapsed into a Malthusian nightmare. As a result, the surviving drell now live on Kahje, a planet poorly suited to them. (See Kepral’s Syndrome below.)
When the hanar rescued the drell, in their gratitude the drell agreed to the Compact, a means by which the drell repay their debt of gratitude by carrying out tasks that the hanar find difficult.
Kepral’s Syndrome
Kepral’s Syndrome is a progressive, non-communicable illness affecting the pulmonary and circulatory systems of drell. It is caused by the mismatch between drell lungs, evolved for Rakhana’s deserts, and high humidity, inescapable on Kahje. Over time, the lungs lose the ability to absorb oxygen. In the final stages, the blood’s oxygen transfer proteins fail to form correctly. The drell victim eventually suffocates to death.
Batarians
Batarian Factbox
Homeworld: Khar’shan
Government: Batarian Hegemony
Status: rogue state
since: 2171 CE
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown (prob. uncommon)
[Mass Effect Wiki]
The batarians are a species of four-eyed humanoid bipeds. Batarian culture places high regard on caste and status, and slavery is so ingrained into their culture that they consider the Council's laws against it to be anti-batarian discrimination.
Batarians were once a Citadel associate species, but when the Council refused to classify the Skyllian Verge as a region of “batarian interest” and permitted humans to colonize it, they closed their embassy in protest. Since then, their interactions with other species has been mostly in the form of slave grabs, black market trade, and acts of terrorism ranging from petty to planet-shattering.
The flow of information between the batarian homeworld Khar’shan and the galaxy-at-large is highly regulated by their government, the Batarian Hegemony. ME3 implies that much of the animosity from batarians toward humans is the result of government propaganda and a powerful police state.
Vorcha
Vorcha Factbox
Homeworld: Heshtok
Government: none (tribal)
Status: independent
since: unknown
Lifespan: 20 years
Form: carbon-based (levo-amino)
Biotics: unknown (prob. very rare)
[Mass Effect Wiki]
The vorcha are a bipedal pre-spaceflight species, whose evolutionary path has no analogue in Earth’s clades. Vorcha possess clusters of non-differentiated cells, giving them a unique ability to morph their developing body to suit the conditions of the vorcha's upbringing, as well as the ability to regrow lost body parts.
Vorcha are reputed to have low intelligence and aggressive, violent behavior, the latter of which being so deeply ingrained that vorcha use violence as their primary form of non-verbal communication. On their homeworld Heshtok, vorcha live in clans which constantly war with one another for scraps of land and resources; over the centuries, their homeworld has been stripped bare.
Vorcha populations away from home are largely descended from stowaways aboard spacecraft unfortunate enough to land on Heshtok; they tend to live one of two lives: either in vorcha-dominated slums living as scavengers on the edge of society (where they are regarded as unusually sentient pests), or as mercenaries in organizations such as the krogan-dominated Blood Pack.
Despite all this, the vorcha are not inherently violent. In an experiment on the mining world Parasc, asari mining corporations adopted and raised vorcha orphans as a labor source, and vorcha adaptability proved to outweigh any propensity toward violence.
Collectors
Collector Factbox
Homeworld: Collector Base
Government: unknown
Status: Reaper
since: 50,000 years ago
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: common
[Mass Effect Wiki]
The Collectors are an enigmatic species with a mix of humanoid and insectoid features. Prior to the events of the Mass Effect games, they were known for paying exorbitant sums for live test subjects, often trading their advanced technologies for slaves counted in the low dozens.
During the course of ME2, it is revealed that the Collectors are servants of the Reapers, and that they are what's left of the Prothean species after 50,000 years of genetic modification and cybernetic augmentation by their Reaper masters.
Their effective “homeworld” is the Collector Base, accessible only via the Omega-4 relay.
Keepers
Keeper Factbox
Homeworld: the Citadel
Government: none
Status: Reaper
since: X million years ago
Lifespan: unknown
Form: carbon-based (chirality unknown)
Biotics: unknown (prob. none)
[Mass Effect Wiki]
The keepers are an eight-limbed insectoid species that exist aboard the Citadel, where they silently carry out maintenance, repair, and custodial tasks. It is not known if they are sentient or sapient. It is speculated that they were created by the Reapers, the result of extensive genetic engineering that converted a previously free-living species into biological robots.
“Extinct”
Protheans
Prothean Factbox
Homeworld: unknown
Government: Prothean Empire
Status: extinct
since: 50,000 years ago
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown (prob. common)
[Mass Effect Wiki]
The Protheans were a species with a mix of humanoid and insectoid features. They died out 50,000 years ago; the reason was originally mysterious, but they turned out to be the most recent victims of the Reapers and their cycles of Harvest.
Much like the ancient Romans on Earth, the Protheans were conquerors who assimilated defeated cultures as citizens into their ever-growing empire. They believed in a principle called the “Cosmic Imperative”, which basically boils down to “might makes right”. The Protheans believed that certain individuals came to embody virtues of the empire; such “avatars” were held up as examples for others to emulate.
By way of cryonic stasis, one Prothean has survived to modern times: a soldier named Javik, the Avatar of Vengeance.
Rachni
Rachni Factbox
Homeworld: Suen
Government: unknown
Status: independent
since: 300 CE
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown
[Mass Effect Wiki]
The rachni are an insectoid species. Over the years, many have mistaken the rachni for mindless creatures of instinct, when the truth is that the rachni are as intelligent as any humanoid species, having built cities on the surface of their homeworld and developed FTL spaceflight.
Rachni have a partial hive mind: the queens use telepathy to “sing” to their children, sharing their thoughts and guiding the young to develop into full adults. Adults can survive being separated from their nest with no ill effect, but juveniles are driven mad by the silence.
Rachni are territorial and isolationist, showing quick aggression to trespassers but with no natural desire to expand their territory through war. They tend to prefer worlds that other species find too toxic to settle, worlds that no one else would want. The galaxy at large is mostly unaware of this, however, as the brutal Rachni Wars have shaped galactic perceptions of rachni behavior.
The Rachni Wars ended when the krogan supposedly drove the rachni to extinction. However, during the events of ME1 on Noveria, this genocide was revealed to be incomplete: Commander Shepard encounters a rachni queen, imprisoned by the villain of the game with the hope of breeding an army of soldier drones. This queen tells Shepard that the rachni were not willing participants in the Rachni War; rather, they were mind controlled by some outside force, which corrupted them by way of a “sour yellow note” (probably the Leviathans) and forced them to go to war. If Shepard chooses to release her, she promises to remember and repay the kindness shown to her, and later games show that she makes good on her word.
Regardless of whether Shepard frees or kills the rachni queen on Noveria, the Reapers appear to be breeding rachni “ravagers” on Utukku. This implies that there are still some free-living rachni somewhere in the galaxy, separate from the queen met on Noveria, and that the Reapers found and corrupted these rachni.
Leviathans
Leviathan Factbox
Homeworld: unknown
Government: unknown
Status: independent
since: X billions of years ago
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown (prob. universal)
[Mass Effect Wiki]
The Leviathans are an ancient spacefaring aquatic species, each individual resembling an enormous squid or cuttlefish hundreds of meters long. They were largely unknown to the modern galaxy, except as rumors and myths, until 2186. During the events of the ME3 [Leviathan DLC], Commander Shepard encounters and interacts with a Leviathan; that interaction is the source of most of our Leviathan knowledge.
An unfathomably long time ago — a billion years into the past, or perhaps more — the Leviathans ruled the galaxy. They possess a natural talent for mind control, a talent which they put to work in enslaving all other complex life in the galaxy. Reaper indoctrination was probably inspired by this Leviathan ability.
They did not respect their thralls as individuals, seeing them only as tools to acquire “tribute”. However, their thralls had enough autonomy that they still developed their own technology. On multiple occasions, the thrall races developed AI technology, only to be destroyed by it. The Leviathans frowned on this, as a dead race brings no tribute.
Seeing themselves as above the concerns of “lesser” species, they created an AI of their own. This AI came to be known as the Catalyst, as it was meant to be the catalyst for peace between organic and synthetic life. It was tasked to consider this problem (of synthetics destroying their creators) and develop a solution which would “preserve” the thrall races. After an unknown number of years collecting data, the AI reached a conclusion: it would construct the Reapers, which satisfied the definition of “preserve” that the AI had been programmed with.
The Leviathans themselves were the first species to be Harvested, and the first Reaper Harbinger was constructed in their image. However, at least one pocket of Leviathans escaped, and their descendants survive in the oceans of 2181 Despoina to this day.
Unique
EDI
See Characters > EDI.
The Catalyst
The Catalyst is an AI constructed by the Leviathans long ago. The Catalyst created the Reapers, and in some sense controls them.
The Thorian
The Thorian was an enormous multi-km² plant-based intelligence on the colony world Feros. It lived for tens of thousands years (at least!) before Commander Shepard fought it and killed it.
The Thorian had a unique form of mind control: the process was initiated via inhalation of spores over a period of weeks, then the Thorian began to telepathically monitor the subjects' thoughts and reward or punish them appropriately. It would use its enthralled animals, especially intelligent life, to tend to its sprawling growth. This ability is one of the few forces capable of overriding Reaper indoctrination: Shiala, an indoctrinated asari, lives out the rest of her life on Feros free of Reaper control, living with the other colonists' thoughts always brushing up against the edge of her mind (the lingering side effect of the Thorian's mind control).
Non-sapient
Varren
Varren Factbox
Homeworld: Tuchanka
Government: N/A, not sapient
Status: N/A, not sapient
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown (prob. rare)
[Mass Effect Wiki]
Varren, sometimes called “fishdogs” for their scales, are creatures native to Tuchanka, the krogan homeworld. Larger than a dog, they fill an ecological niche similar to that of Earth’s wolves. Adaptable pack hunters and scavengers, they breed rapidly and usually outcompete native wildlife when introduced to new planets. Trained varren are frequently used by krogan and batarians as beasts of war. On the other hand, some people keep varren as pets.
Thresher Maws
Thresher Maw Factbox
Homeworld: Tuchanka
Government: N/A, not sapient
Status: N/A, not sapient
Lifespan: unknown
Form: carbon-based (levo-amino)
Biotics: unknown (prob. very rare)
[Mass Effect Wiki]
A thresher maw is an enormous worm-like burrowing carnivore native to Tuchanka, the krogan homeworld. They have spread to many worlds beyond their original home because they reproduce by spores, and said spores are hardy enough to survive deep space and re-entry. The large ones can stand more than 30 meters tall when they choose to burst from the ground.
Thresher Maws are solitary and incredibly territorial predators. They will not tolerate another predator within their home range, especially not another thresher maw. They are adept at ambush tactics, lying in wait within their underground nest until they sense the movement of prey on the surface, at which point they burst from the ground, subdue the prey with their spiny claws and corrosive spit, then consume it.
Additionally, the Mass Effect lore has it that thresher maws can subsist on minerals and photosynthesis, and unintuitively thrive on thin-atmosphere and no-atmosphere worlds.
(Enormous worm-like burrowing carnivores attracted to surface movement? Dune afficionados may notice some familiar traits.)