Known for their militaristic and disciplined culture, the turians were the third race to join the Citadel Council. They gained their Council seat after defeating the hostile krogan for the Council during the Krogan Rebellions. The turians deployed a salarian-created biological weapon called the genophage, which virtually sterilised the krogan and sent them into a decline. The turians then filled the peacekeeping niche left by the once-cooperative krogan, and eventually gained a Council seat in recognition of their efforts.
Originally from the planet Palaven, turians are best known for their military role, particularly their contributions of soldiers and starships to the Citadel Fleet. They are respected for their public service ethic—it was the turians who first proposed creating C-Sec—but are sometimes seen as imperialist or rigid by other races. There is some animosity between turians and humans, largely due to the turian role in the First Contact War. This bitterness is slowly beginning to heal—as shown by the cooperation of the two races on the construction of the SSV Normandy—but many turians still resent humans, and vice versa.
Turians typically stand over 6 feet (1.8 meters) tall, have two long, proportionately thick fingers and an opposable thumb on each hand, each tipped with talons, and a set of mandibles around their mouths. The most distinguishing feature of turians is their metallic carapace, which contains trace amounts of thulium. The turians evolved this trait as a defense against the greater levels of solar radiation that penetrate their homeworld's weak magnetic field.
Turian features are avian, making them resemble humanoid birds or raptors. However, unlike most Earth avian creatures, turians are viviparous and give birth to live young. In 2165, David Anderson claimed that turians reminded him of the evolutionary link between birds and dinosaurs. Turians are also recognisable by their voices, which have a distinctive flanging effect. Males and females do not differ greatly in terms of physical appearance, but female turians lack the sweptback cranial crests of their male counterparts and possess larger, cat-like eyes. The lifespan of a turian is comparable to that of a human.
Turians exhibit the characteristics of predators rather than those of prey species (compare to krogan biology). Their forward-facing alert eyes give the impression that they possess outstanding eyesight and their teeth and jaws mimic the structures possessed by apex predators such as crocodiles or ancient, carnivorous dinosaurs. Their talons on both their feet and hands seem capable of ripping flesh. As such, their diet is primarily meat-based. Their slender bodies also seem to suggest that they are also capable of moving at high speeds.
The turian homeworld, Palaven, has a metal-poor core, generating a weak magnetic field and allowing more solar radiation into the atmosphere. To deal with this, most forms of life on Palaven evolved some form of metallic "exoskeleton" to protect themselves. Their reflective plate-like carapace makes turians less susceptible to long-term, low-level radiation exposure, but they do not possess any sort of "natural armor". A turian's thick skin does not stop projectiles and directed energy bolts. They can, however, experience the equivalent of a "massage": turians can feel vibrations through the carapace with the use of a hammer.
Turian blood has a dark blue colouration. Carapace wounds and subsequent scarring may appear red, however.
Although life on Palaven is carbon-based and oxygen-breathing, it is built on dextro-amino acids. This places the turians in a distinct minority on the galactic stage; the quarians are the only other sapient dextro-protein race. The food of humans, asari, or salarians (who evolved in levo-amino acid-based biospheres), will at best pass through turian systems without providing any nutrition. At worst, it will trigger an allergic reaction that can be fatal if not immediately treated.
The turian mechanic Lilihierax on Noveria uses the idiom, "if you can polish enough gizzard". This suggests that the turians have a digestive system similar to birds and reptiles on Earth, some of whom swallow stones to help break down harder foods in the stomach.
Turian civilization spans fifteen thousand years of history. Before the dawn of their civilization, the race was known to elder spacefaring species like the Protheans, who viewed them as primitive as the other ruling races of the modern era.
As with the other future Council species, the turians have a mass relay within their system. The first turian starship to travel through a relay was called the THV Ravuna.
The turians had already discovered several mass relays and spawned colonies throughout the galaxy when the asari reached the Citadel. At about the time the asari were forming the Council with the salarians, the turians were embroiled in a bitter civil war next door. The Unification War, as it was later named, began with hostilities between the colonies furthest from the turian homeworld, Palaven.
These colonies were run by local chieftains, many of whom had distanced themselves from the Hierarchy. Without the galvanizing influence of the government, the colonies became increasingly isolated and xenophobic. Colonists began wearing emblems or facial markings to differentiate themselves from members of other colonies and open hostilities became common.
When war finally broke out, the Hierarchy maintained strict diplomacy and refused to get involved. After several years of fighting, less than a dozen factions remained and the Hierarchy finally intervened. By that time, the chieftains were too weak to resist; they were forced to put an end to the fighting and renew their allegiance to the Hierarchy. Though peace was restored, it took several decades for animosity between colonists to fade completely. To this day, most turians still wear the facial markings of their home colonies.
In the midst of the Krogan Rebellions, the Citadel Council made first contact with the turians. At the Council's behest, the turians brought their considerable war machine to bear on the krogan, now a recognized threat. While the initial turian offensive was successful in routing many krogan warrior bands, it provoked a massive counterattack from the krogan which devastated several turian colonies. Three turian worlds were rendered completely uninhabitable after the krogan used fusion torches to throw asteroids at them, and the bloodiest battle in turian history occurred at Digeris, where the planet was severely bombarded and the turians sacrificed many frigates and fighters to take out a fleet of krogan dreadnoughts. Rather than scaring off the turians with this show of force, the turians only fought with more resolve to quash the krogan utterly. Eventually, the turians implemented the salarian-developed genophage. With their advantage in numbers removed, the majority of krogan were subdued by 800 CE, although scattered insurgent actions would continue for decades.
By 900 CE, the turians were granted full membership on the Citadel Council in gratitude for their service during the Krogan Rebellions. The turian military fills the military and peacekeeping niche left by the decimated krogan.
In 2157 CE, following Council laws in place since the Rachni Wars which prohibited the activation of uncharted mass relays, a turian force opened fire on explorers from an as yet unknown race: humanity. One human starship managed to escape and warn the Systems Alliance, which retaliated and destroyed several turian vessels. The situation quickly escalated to war.
Over the next several weeks, the outnumbered Alliance lost multiple scouting parties and patrols to turian offensives. The conflict came to a head when a turian fleet broke through Alliance lines and besieged the human colony of Shanxi. With no other options, the Alliance garrison on Shanxi surrendered, and the turians proceeded to occupy the world, confident that the majority of Alliance forces had been defeated. However, one month later the Alliance's Second Fleet caught the turian occupiers by surprise and evicted them from the planet. Both sides began preparations for a protracted interplanetary war.
Before that could happen, the Citadel Council intervened and revealed the galactic community to humanity. Terms of peace were negotiated and the conflict effectively brought to an end. The turians were ordered by the Council to give heavy reparations to the Alliance for their part in instigating the conflict, known to the galaxy as the "Relay 314 Incident". Mistrust between both races would linger for years to come.
Since the Unification War, turians normally wear elaborate tattoos marking their colony of origin, though it is not known which markings distinguish which colony or if color has any meaning. These markings are usually white — particularly on turians with darker carapaces — but can be of other colors such as blue for Garrus Vakarian or red for Nyreen Kandros. The lack of facial markings is looked down upon in turian society; the turian term "barefaced" refers to one who is beguiling or not to be trusted. It is also a slang term for politicians. For male turians at least, complimenting a potential partner's waist or head fringe seems to be a way of expressing attraction. Male grooming practices for attracting potential mates, for example if going out on dates, include filing their talons and buffing their fringes. Turian society is highly regimented and very organized, and the species is known for its strict discipline and work ethic. Turians are willing to do what needs to be done, and they always follow through. They are not easily spurred to violence, but when conflict is inevitable, they only understand a concept of "total war."