Mass Effect Wiki
Mass Effect Wiki
Disambiguous This article is about the species. For information about the enemy unit, see Krogan (enemy).

The krogan are a species of large reptilian bipeds native to the planet Tuchanka, a world known for its harsh environments, scarce resources, and overabundance of vicious predators. The krogan managed to not only survive on their unforgiving homeworld, but actually thrived in the extreme conditions. Unfortunately, as krogan society became more technologically advanced, so did their weaponry. The end result is that they destroyed their homeworld in a nuclear war that reduced their race into primitive warring tribes.

With the help of the salarians, the krogan were "uplifted" into galactic society, and lent their numbers and military prowess to bring an end to the Rachni Wars. Ironically, after the rachni were eradicated, the rapidly-expanding krogan became a threat to the galaxy in turn, starting the Krogan Rebellions and forcing the turians to unleash the genophage. This genetic "infection" dramatically reduced fertility in krogan females, causing a severe drop in births secondary to prenatal and postnatal death and, ultimately eliminating the krogan's numerical advantage.



Due to the brutality of their surroundings, natural selection has played a significant role in the evolution of the krogan. Unlike most sentient species, krogan eyes are wide-set - on Earth, this is common among prey animals, and in this case it gives the krogan 240-degree vision, giving them greater visual acuity and awareness of approaching predators. Krogan eyes have narrow pupils. Their irises may be red, green, amber, or blue in color.

Prior to the genophage, krogan could reproduce and mature at an astonishing rate. Females are known to produce clutches of up to 1,000 fertilized eggs over the course of a year. In present conditions, according to EDI, the odds of a krogan successfully giving birth to two females stand at 1 in 2,000, though krogan biology is slowly adapting to the virus.

Their large shoulder humps store fluids and nutrients in much the same way as an Earth camel, enabling them to survive extended periods without food or water. In particular they require very little water intake; a 55-gallon tank system can sustain an entire colony of krogan for over 10 years. A bigger shoulder hump is seen as a sign of high status, showing how successful an individual krogan is at hunting. Their thick hides are virtually impervious to cuts, scrapes or contusions, and they are highly resistant to environmental hazards, including toxins, radiation, and extreme heat and cold. Consequently their diets can include food and drink which would prove very dangerous to other species—a fact reflected in the krogan liquor of choice, ryncol, which is said to "hit aliens like ground glass".

Younger krogan have yellow or green markings on their hides. These markings darken to brown or tan over time, showing their age. Younger krogan tend to have looser plates on their head with soft spots in between. When they grow older the plates grow together to form one whole.

Krogan typically stand over 7 feet. Heavy creatures, krogan have been known to weigh at least 150 kilos, upwards of nearly 200 kilos for above-average specimens. Some particularly large krogan weigh in at about 800 pounds (~362 kilos), estimated independently by themselves and by non-krogan observers. Biotic individuals are rare, though those who do possess the talent typically have strong abilities.

The most amazing physiological feature of krogan biology is the multiple instances of major organs. These secondary (and where applicable, tertiary) systems are capable of serving as back-ups in the event of damage to the primary biological structures. They have, for example, two hearts, four lungs, and four testicles. This reflects in their slang, where they often speak about a "quad" where a human would use the words "balls" or "pair". Krogan also have a secondary nervous system using a neuroconductive fluid, meaning they are almost impossible to paralyze. Krogan bleed a yellow or orange fluid when shot, which may be this fluid or actual blood.

Aside from redundant systems, the legendary krogan "blood rage" adds to the race's reputation for being notoriously difficult to kill or incapacitate in normal combat scenarios. In this state, krogan become totally unresponsive to pain and will fight to the death regardless of injury level, with the side effect of reducing their capacity for logic and self-control.

Sheer physical hardiness means an individual krogan can expect to live for centuries. Krogan can live for well over a thousand years, as evidenced by Warlord Okeer, a veteran of the Krogan Rebellions who died (of decidedly unnatural causes) well over a thousand years after the Rebellions ended. Nakmor Drack is another example of their long life-spans, a 1,400-year-old veteran of the Krogan Rebellions who joined the Andromeda Initiative to voyage to the Heleus Cluster.

Despite their natural propensity for toughness, krogan do have physical weaknesses. According to Zaeed Massani, if one lodges a knife at a certain spot near the frontal plate on a krogan's head, the plate can be ripped off. It is apparently the one thing krogan do fear.


Krogan history at a glance: nuclear devastation, salarian interference, return to desolation

Ancient krogan society was once rich with cultural, architectural, and artistic accomplishments. However, the krogan birth rate exploded despite the natural limits of their predatory homeworld once they achieved industrialization. Technology made life "too easy" for them, so when they looked for new challenges they found those in each other. Wars were fought over dwindling resources as the krogan expanded.

Four thousand years ago, at the dawn of the krogan nuclear age, battles to claim the small pockets of territory capable of sustaining life escalated into full scale global war. Weapons of mass destruction were unleashed, transforming Tuchanka into a radioactive wasteland. The krogan were reduced to primitive warring clans struggling to survive a nuclear winter of their own creation, a state that continued until they were discovered by the salarians two thousand years later.

Rise of the krogan[]

The krogan were liberated from their primitive state by the salarians, who "culturally uplifted" the race by giving them advanced technology and relocating them to a planet not cursed with lethal levels of radiation, toxins or deadly predators. The salarians even gave the krogan the means to stabilize Tuchanka's atmosphere by means of the Shroud.

Attacking krogan

But the salarian intervention was not without an ulterior motive. At the time the Citadel was engaged in a prolonged galactic war with the rachni, a race of intelligent space-faring insects. The salarians hoped the krogan would join the Citadel forces as soldiers to stand against an otherwise unstoppable foe. The plan worked to perfection: within two generations the rapidly breeding krogan had the numbers not only to drive back the advancing rachni, but the ability to endure the harsh conditions of the rachni worlds. They were able to pursue them to their home worlds, find the rachni queens, and eradicate the entire species.

For a brief period the krogan were hailed as the saviors of the galaxy and were given not only the conquered rachni worlds but other planets in Citadel space to colonise, in gratitude for their help. The Citadel Council even commissioned a statue for the Presidium—the Krogan Monument—to honor the krogan soldiers who died defending Citadel space.

But without the harsh conditions of Tuchanka to keep their numbers in check, the krogan population swelled to unprecedented numbers. Overcrowded and running out of resources, the krogan spread out to forcibly claim other worlds—worlds already inhabited by races loyal to the Citadel. There was always "just one more world" needed. The final straw was when the krogan began settling the asari colony of Lusia. When the Council ordered them to leave, Overlord Kredak, the krogan ambassador, stormed out of the Chambers, daring the Citadel races to take their worlds back. War broke out soon afterward.

Rebellion and decline[]

An already-ravaged Tuchanka further depopulated by the genophage

The resultant Krogan Rebellions continued for nearly three centuries. The krogan sustained massive casualties, but their incredible birth rate kept their population steadily increasing. They also had no compunction about resorting to extreme tactics, such as using redirected asteroids as weapons, almost rendering several planets uninhabitable. Soon their victory seemed inevitable. In desperation, the Council turned to the recently discovered Turian Hierarchy for aid. The turians unleashed the genophage on the krogan home worlds: a bio-weapon engineered by the salarians. The genophage caused near-total infant mortality in the krogan species, with only one birth in every thousand producing live offspring.

No longer able to replenish their numbers, the krogan were forced to accept terms of surrender. For their role in quelling the Krogan Rebellions, the turians were rewarded with a seat on the Citadel Council. The krogan, on the other hand, still suffer from the effects of the genophage.

Over the last millennium krogan numbers have steadily declined, leaving them a scattered and dying people. Some try bizarre treatments for the genophage, including testicle transplants. But, faced with the certainty of their extinction as a species, most krogan have become individualistic and completely self-interested. They typically serve as mercenaries for hire to the highest bidder, though many still resent and despise the Citadel races that condemned them to their tragic fate. Wrex comments disdainfully that clubs, bars and brothels often try to hire krogan bouncers, reducing his people to some kind of status symbol.


The modern krogan lifestyle

Despite announcements about failed, krogan-funded research into the genophage by 2183, most krogan have not worked toward a cure as they are more interested in combat than science. Unless one is discovered and used, the extinction of the krogan seems inevitable.

In 2185, Mordin Solus explains that the krogan are in fact evolving to undo the damage of the genophage. To prevent overpopulation, Mordin's Special Tasks Group team created and applied a modified version of the genophage, which he claims will keep the population down but still allows for a viable population, indicating the krogan race isn't as doomed as they believe. Mordin states that both the original and new genophage were designed to stabilise the krogan birth rate at pre-industrial levels—one viable birth per thousand.

Given the prodigious krogan birth rate, it would appear that the enormously violent nature of krogan culture is actually responsible for their dwindling numbers. Ironically, this means that if the krogan were not so convinced that they, as a species, are doomed, and consequently spent less time roaming the galaxy spoiling for a fight, their numbers might increase—they are essentially being killed by their own fatalism.

The Reaper War[]

In 2186, the Reapers invade Earth forcing Commander Shepard to look for allies, which includes the krogan. The turian army needs the krogan to help them defend their homeworld of Palaven and the krogan agreed to do this and help rescue Earth from the Reapers in exchange for a cure for the genophage. Depending on Shepard's actions in 2185 with Maelon's research data, Mordin or Padok Wiks will manage to create a cure with the help of Eve, one of the last fertile female krogan.

If Shepard persuaded Mordin to keep the data, then Eve will live through the procedure, and if not, then she will die. Shepard and the team head to the Shroud to disperse the cure, despite the fact the STG sabotaged it to prevent this from happening. Shepard can allow the salarian scientist to override the sabotage and release the cure, which will result in his death, kill him to prevent the cure from being released, or convince him to fake the cure.

The krogan are back to building megalithic structures instead of destroying them if they're freed from the genophage

If the genophage is cured, the krogan pledge their support in the war against the Reapers. If the cure was sabotaged and Urdnot Wrex leads the krogan, he will discover the sabotage and withdraw krogan support. However, if Urdnot Wreav leads, then the krogan are fooled into believing that the genophage is cured.

The fate of the krogan varies wildly by the war's end. If the cure was sabotaged and organics and synthetics weren't merged, the krogan are left as moribund as before, possibly headed toward extinction. If the cure was real, the krogan are shown repopulating. They also aid in Tuchanka's reconstruction if Wrex is the leader. If Wreav is the leader, he attempts to incite the resurgent krogan for his own purposes, either confronted by Eve if she's alive or succeeding if not. If organics and synthetics were merged, the massive pyramids constructed by the krogan forebears on Tuchanka are restored to their former glory, and with those, the race itself.

Andromeda Restart[]

In 2185, the majority of Clan Nakmor plus a few representatives from other clans departed the Milky Way with the Andromeda Initiative to settle the Andromeda galaxy. As they were still grappling with the genophage, they underwent gene therapy while in cryosleep and managed to improve their offspring viabilities by a small, but significant, percentage.

About 600 years later, the disastrous arrival of the Nexus in Andromeda ultimately resulted in a mutiny violently crushed by krogan assets. The Nexus leadership reneged on their deal to give the krogan a seat at the leadership council in exchange for their help, prompting their departure from the space station with the mutineers to seek their fortunes elsewhere.

The krogan settled on Elaaden and named their stronghold there New Tuchanka. Overlord Nakmor Morda leads the race while Nakmor Kesh stayed behind on the Nexus to ensure the krogan still have allies there.


Body armor is normal krogan wear on Tuchanka

The harsh krogan homeworld conditioned the krogan psychology for toughness just as it did the body. Krogan have always had a tendency to be selfish, unsympathetic, and blunt. Sometimes, when krogan disagree, one of them will head-butt the other to show dominance. They respect strength and self-reliance and are neither surprised nor offended by treachery. Their worst insult is to call someone "not worth killing".

The weak and selfless do not live long. In their culture, "looking out for number one" is simply a matter of course. Krogan have powerful territorial instincts which serve them well in combat, but can create problems; when traveling on starships, for example, krogan find sharing quarters nearly impossible.

Calling a krogan "weak" invites violent retaliation: "phage-lucky" is an insult that denotes a "runt" only reached adulthood because the genophage killed the kids stronger than them. Younger generations of krogan use it to taunt their elders.

Most krogan trust and serve no one but themselves. This solitary attitude stems in part from a deep sense of fatalism and futility, a profound social effect of the genophage that caused krogan numbers to dwindle to a relative handful. Not only are they angry that the entire galaxy seems out to get them, the krogan are also generally pessimistic about their race's chances of survival. The surviving krogan see no point to building for the future; there will be no future.

The krogan live with a generally violent and short-sighted attitude of personal gain. Their version of cooperation is reflected in one of their sayings: "Seek the enemy of your enemy, and you will find a friend."

Tank-bred krogan are generally looked down upon in krogan society, probably more so than the clanless. Traditionalists won't even allow them to be accorded adult status, and with it equal voice in the tribe, although more enlightened clans can let them participate in their rites and rise up the ranks through their own merits.

Krogan females tended to be dressed from head to toe

Female krogan rarely leave their home worlds, focusing on breeding in an attempt to keep krogan numbers from declining too quickly. The few remaining fertile females who can carry young to term are treated as prizes of war, to be seized, bartered or fought over. However, purposefully harming a female krogan is a crime worthy of banishment or worse.

By the 2180s, krogan females live in clans separate from that of the males. Envoys are sent out from the female clans to determine who amongst the males is worthy to visit the female clans. Due to the effects of the genophage and the lack of fertile females, this happens often and many male krogan sire children from one female. Krogan females also appear much more level-headed than males; 'the brains to their brawn,' so to speak.

Krogan children are raised within the females' camps. On occasion the females send them over to the males for training. If a male wishes to claim his offspring, he can request the right of parentage. According to Eve, however, krogan do not name their infants very well: the males get drunk on sovak juice and have belching contests. Whatever happens to sound like a word becomes a name.

Marks of the krogan psyche past and present can be observed in their architecture and infrastructure. Ancient krogan built towering pyramidal edifices, gigantic monuments and cities, complete with interior paintings of what could be called art. Millennia later, the ruins haven't yet lost to the ravages of time and survived to remind the latter-day krogan of their glory days, although places like the "city of the ancients" were long-abandoned by then.

Every krogan building is built huge and to last. Even hospitals are built strong enough to withstand a bunch of krogan undergoing blood rage. Blocky ruins litter Tuchanka's surface, a portion of them still livable by krogan standards.

Krogan do not hold weddings, but they do participate in (and appreciate) courtship rituals.

In the Andromeda galaxy, gender segregation has been relaxed owing for the need of a unified krogan front to build their civilization from the ground up. Females are likely to have their specializations same as the males, and no longer singularly focused on breeding.


A meeting of krogan at the Hollows

Krogan are not shown to have strong religious beliefs. The closest they come is to establish ritualistic burial grounds called the Hollows, where the skulls of their ancestors are displayed to remind them of "where we all come from, and where we all go." The Hollows are as sacred as any krogan place can be, and violence there is forbidden.

Ancient krogan deities include Vaul, a god who stood watch for the enemies of his pantheon. The planet Vaul is named for this god, and its moons are named for Vaul's myriad eyes and ears. Another is Uzin, a god of vengeance who also has a planet named after him.

Krogan are also shown to believe in some form of afterlife. Several krogan mention a place called "the Void" which krogan go to when they die. Additionally, the planet Kruban takes its name from a mythological paradise in which honorable krogan warriors feast on the internal organs of their enemies.


Krogan tradition is steeped in ritual. When a krogan is born, he suffers the Rite of Life. When he comes of age, he undergoes the Rite of Passage. If he wishes to be considered for breeding, he must take the Rite of Honor. When facing a new enemy, the Rite of Firsts is invoked. If two krogan are quarreling with each other, the Rite of Union may serve as a way to heal the bond between them by giving the pair a mutual enemy to fight. If one wishes to take over clan leadership, the Rite of Authority determines whether the current leader keeps his post or loses it to the challenger.

Positions of power also bear the responsibility of more rites, like being clan leader or shaman. The Rite of Passage and all other rites and traditions are preserved by the clan shaman. A shaman can be of either gender: they must undergo lengthy and torturous rites to assume the position, and is required to give up their name. Because of this level of commitment, the shaman is one of the most respected members of a clan.

The krogan have at least two ways of formally dealing with their dead. Suicides are left for scavengers to feed upon. Another is via funeral pyre, where the shaman eulogizes the dead and symbolically consigns it to the Void. Known instances of the pyre include krogan who have died a particularly valorous death, e.g. by saving the future of the entire race.


Little is known about krogan language except for a few non-translatable terms. Some terms are specific to certain krogan clans, such as "Aralakh", which was taken from Clan Raik. Known krogan words are listed below.

When spoken word fails, krogan demonstrate their eloquence with body language.
  • Aralakh - "Eye of Wrath"
  • hrakhor - pejorative, referring to unskilled henchmen by context
  • korbal - roughly, "victory or death"
  • krantt - a warrior's most trusted allies
  • ru'shan - "Child of my Blood"
  • ruzad - "judge"
  • Trobror - "cinder" or "ash heap"

Krogan names are composed of two parts, a clan name followed by a given name. At birth, krogan are identified by their given name only. A clan name is bestowed after krogan complete the rite of passage of the clan they wish to join.

While krogan actions speak louder than words, linguistic quirks are not unknown to them. Known krogan idioms include "like a thresher maw pet", indicating something is unpredictable.


Krogan are divided into numerous clans. Membership in a clan allows a krogan to own property, join the army and apply to serve under a battlemaster. Clan diplomats represent the strength of their people to other clans, and thus make it their job to look intimidating lest their clan be targeted for conquest.

Young krogan undergo a rite of passage that is overseen by a shaman respective to the clan the krogan wishes to join. In Clan Urdnot, this rite consists of battling various wild fauna on Tuchanka, ending with an encounter with a thresher maw. Merely surviving for five minutes is considered proof of worthiness, but killing the thresher maw increases the initiate's prestige and standing. In Clan Nakmor, it's claimed that it isn't so much a rite of passage as a "death trip", and surviving entails membership into the clan.

Few outsiders have seen a rite of passage take place, even though there are no rules in krogan tradition that state that a non-krogan can't help with the undertaking of the rite by acting as the participant's krantt.

Known krogan clans:

  • Clan Bragus - Bragus Thul plays as a quarterback in North-American-Union-Rules football.
  • Clan Dahmbra - one of several clans with individuals that joined the Andromeda Initiative.
  • Clan Drau - Drau Sorze is a "ruzad", or "judge", in the Republic of Ghurst on Tuchanka.
  • Clan Forsan - this clan's leader declared being hit by pyjak dung is grounds for executing the trader responsible for introducing them to Tuchanka.
  • Clan Ganar - Ganar Wrang, an exiled krogan battlemaster, founded the Blood Pack mercenary group.
  • Clan Gatatog - led by Gatatog Uvenk on Tuchanka.
  • Clan Graken - Graken Dhal, a warlord, involved in the bombardment of Digeris during the Krogan Rebellions.
  • Clan Gulnaz - one of several clans with individuals that joined the Andromeda Initiative.
  • Clan Hailot - clan leader Hailot Wrund controlled Garvug prior to the corporatist invasion in 2185.
  • Clan Jair - one of several clans with individuals that joined the Andromeda Initiative.
  • Clan Jorgal - a clan known to have one of the longest krogan breeding lines and oldest bloodlines.
  • Clan Jurdon - an enemy of Clan Urdnot on Tuchanka.
  • Clan Kariss - one of several minor clans with individuals that joined the Andromeda Initiative.
  • Clan Khel - Khel Burrum is a krogan competing at Pinnacle Station.
  • Clan Kohrr - one of several clans with individuals that joined the Andromeda Initiative.
  • Clan Kormer - one of several clans with individuals that joined the Andromeda Initiative.
  • Clan Korten - a clan known for making klixen-roasted varren jerky with their own signature pyjak sauce.
  • Clan Nakmor
  • Clan Quash - Quash Hurgott is a Blood Pack commander.
  • Clan Raik - source of the word "Aralakh", meaning "Eye of Wrath", which became the common name used by the galaxy to refer to Tuchanka's star.
  • Clan Ravanor - the clan runs a mining operation on Tuchanka; Warlord Ravanor Tusk is a clan member.
  • Clan Shath - Shath Norda survived a trip to the planet Kruban.
  • Clan Strogjaw - Strogjaw Grog is a member who joined then deserted the Andromeda Initiative.
  • Clan Talyth - a clan that attempted to rebuild a dreadnought on Tuchanka with the help of turian duarch Ellis Valterus.
  • Clan Thax - the clan of krogan businessman Thax Vorak.
  • Clan Urdnot
  • Clan Weyrloc
  • Clan Wik - one of several clans with individuals that joined the Andromeda Initiative.


Milky Way[]

After their defeat in the Rebellions, the very concept of krogan leadership was discredited. Where a warlord could once command enough power to bring entire solar systems to heel and become Overlord, these days it is rare for a single leader to have more than a thousand warriors swear allegiance to him. It is speculated that their instinctive aggression and territorial nature prevent the krogan from forming any kind of centralized government or parliament that is not based on fear or obedience.

The krogan homeworld of Tuchanka is divided into multiple nation-states, including the Republic of Ghurst, which was embroiled in a rebellion in 2185.


The majority of krogan who departed the Milky Way belong to Clan Nakmor, and consequently answer to the authority of clan leader Nakmor Morda. After the establishment of New Tuchanka on Elaaden, Morda declared herself Overlord of all krogan in the Heleus Cluster.


A krogan battlemaster and geth troopers

Traditional krogan tactics were built on attritional mass-unit warfare. Equipped with cheap, rugged gear, troop formations were powerful but inflexible. Command and control was very centralized; soldiers in the field who saw a target contacted their commanders behind the lines to arrange fire support.

Since the genophage, the krogan can no longer afford the casualties of the old horde attacks. The Battle Masters are a match for any ten soldiers of another species. To a Battle Master, killing is a science. They focus on developing clean, brute-force economy of motion that exploits their brutal strength to incapacitate enemies with a swift single blow of overwhelming power. This change of focus from mass-unit warfare to maximal efficiency has increased employment demand in the fields of security and "muscle for hire." Due to the unsavory reputation of the krogan, most of these jobs are on the far side of the law.

Battle Masters are not "spit and polish," but they do believe in being well-armed and equipped, preferably with a gun for each limb. They are callous and brutal, but methodical and disciplined. They use any means at their disposal to achieve their goals, no matter how reprehensible. Hostage-taking and genocide are acceptable means to ensure a quiet occupation with few krogan casualties.

With the genophage keeping natural krogan numbers down, some factions turned to the genetic sciences to mass-produce legions of tank-bred warriors

The krogan serving with Saren's forces appear to be returning to the old style of mass attritional combat. They also work in close cooperation with supporting geth units, who fill in the roles occupied by combat drones in other armies.

Biotics are rare among the krogan, especially since the practice of surgically creating krogan biotics has been discontinued (due to the high mortality rate). Those that exist are viewed with suspicion and fear. The krogan see this aura of fear as a useful quality for an officer, and often promote them. Combat drones and other high-tech equipment are likewise in short supply.

Krogan military doctrine has a different take on what "scouting and reconnaissance" means. While other races' scouts prefer stealth and discretion in carrying out their tasks, krogan scouts instead opt to deal psychological warfare when they find the enemy by way of occasional harassment or intentionally exaggerating their numbers. The reasoning is that it is a lot easier to count enemy numbers when some of them get blown up.

The hordes of Tuchanka

Weapons developed by the krogan include the Graal Spike Thrower shotgun and Striker Assault Rifle. The Graal was designed specifically for hunting thresher maws, and so has predictably grisly effects when used on humanoid targets. The Striker is a fully-automatic weapon that fires high-impact explosive slugs with high recoil, making it a difficult weapon for non-krogan to keep on target despite it being designed with them in mind. Krogan also use a large infantry fighting vehicle named Tomkah.

The krogan once possessed a powerful fleet that included many dreadnoughts. Since the end of the Krogan Rebellions, however, they have been demilitarized, prohibited from constructing warships. This ban is enforced by the Council Demilitarization Enforcement Mission arm of the Citadel Council, which maintains garrisoned outposts throughout the Krogan DMZ. Every few years, another krogan warlord violates the ban, but usually an alliance of rivals ends his dreams of hegemony before Citadel forces even have to fire a shot.

Relics of the Krogan Rebellions, such as defunct long range ground-to-space anti-ship batteries that dot Tuchanka's surface, serve as monuments to the krogan's past glory and military might, but have little practical value.

Notable Krogan[]

Krogan Worlds[]

Milky Way[]



See Also[]