A sapient race native to Tuchanka. The krogan were a dying species trapped in a downward spiral of violence. With the biological weapon known as the genophage preventing all but a handful of births, the krogan were shunned by the Citadel worlds they had once saved and later turned on. Some hired themselves out as mercenaries, assassins or muscle for various organized crime syndicates; others managed to make a living through piracy. Many krogan still considered themselves at war with the galaxy at large, incorporating themselves into small war parties or clans, traditionally led by warlords. Increasingly, though, clans took to fighting amongst themselves for territory, resources, and those few krogan females still capable of producing offspring. With the lifting of the Genophage, this proud but wounded race has an opportunity to reclaim a place of power and influence in the galaxy -- though not all agree with Clan Urdnot's measured approach.


Over millions of years, the struggle to survive larger predators, virulent disease, and resource scarcity turned the early krogan into quintessential survivors. Perhaps the most telling indicator of Tuchanka’s lethality is the krogan eyes. Although they’re a predator species by any standard definition, their eyes evolved to be wide-set, like those of prey animals on Earth. Krogan eyes have a 240-degree arc of vision, better suited for spotting enemies sneaking up on them than for pursuit. Krogan eyes have narrow pupils. Their irises may be red, green, amber, or blue in colour.

Their thick hides are virtually impervious to cuts, scrapes or contusions, and they’re highly resistant to environmental hazards, including toxins, radiation, and extremes of heat or cold. Consequently, their diets can include food and drink which would be dangerous to other species -- a fact reflected in the krogan liquor of choice, ryncol, which is said to “hit aliens like ground glass”.

Physically, the krogan are nigh-indestructible, with a tough hide impervious to any melee weapon short of molecular blades. While they feel pain, it doesn’t affect their ability to concentrate. Rather than a nervous system, they have an electrically conductive second circulatory system. A krogan can therefore never be paralyzed -- they may lose fluid, but it can be replaced by the body in time. 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 and four lungs.

The large shoulder hump stores fluids and nutrients, enabling them to survive extended periods without food or water. A bigger hump is seen as a sign of high status, showing how successful an individual krogan is at hunting.

Having redundant biological systems makes krogan extremely difficult to kill or incapacitate in normal combat scenarios. Sheer physical hardiness also means that individual krogan can expect to live for many centuries. Lifespans of well over a thousand years aren’t unusual.

Blood Rage

Feared throughout the galaxy as nightmarishly violent warriors, the krogan are both aided and hobbled by their legendary “blood rage”. In the grip of this madness, krogan become seemingly invincible, but are merely totally unresponsive to pain. “Blood-enraged” krogan fight regardless of injury level, to the extent that krogan shorn of all four limbs continue gnashing past brain death until total somatic death. The supremely resilient, hyper-violent blood rage is the synergy of two aspects of krogan neurology. The first is a positive feedback loop in which adrenalin, also activated by fear or rage, suppresses serotonin, the brain chemical that induces serenity. The second is the over-developed krogan limbic system. In krogan, as in humans, fear or rage shifts mental control from the frontal lobes, responsible for reasoning, to the limbic system, responsible for aggression and survival. During that shift, krogan and humans exhibit diminished capacity for logic and self-control. Prior to the ecological devastation of Tuchanka, blood rage was extremely rare among the krogan. Back then, while all krogan were capable of heightened anger and violence in fight-or-flight scenarios, almost none experienced insensitivity to pain. The one percent who did were those suffering serotonin-suppression. At that time, krogan society regarded the condition as pathological, and medicated or imprisoned sufferers to protect them and society. Following nuclear ecocide four millennia ago, evolution selected only those krogan afflicted with blood rage for survival. Today there is no living memory among the krogan of a life without mindless, murderous fury.


The few krogan biotics are extremely powerful, and often train to become krogan battlemasters. Before the genophage, biotic krogan who enlisted in the military rose quickly through the ranks; the other soldiers were in fear and awe of them, and their superiors recognized that they’d command respect. The krogan developed a surgical procedure that was able to confer biotic ability, but the operation had a high mortality rate, so was discontinued following the release of the genophage.

Krogan biotics eat and drink a great deal more than other krogan, due to the stress of biotic use, but only when they’ve exerted themselves. A krogan’s natural resistances and regenerative factors means that they don’t suffer biotic degenerative diseases or other failures of the nervous system.


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. They respect strength and self-reliance, and are neither surprised nor offended by treachery. The weak and selfless simply don’t live very 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 in other scenarios. When traveling on starships, for example, krogan find sharing quarters nearly impossible.

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, in the modern era it was rare for a single leader to have more than a thousand warriors swear allegiance to him. It’s speculated that their instinctive aggression and territorial nature prevent the krogan from forming any kind of centralized government or parliament not based on fear or obedience.

Culture and Mythology

Krogan Language


Krogan have established ritualistic burial grounds called the Hollows, where the skulls of their ancestors are displayed. This reminds 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.

Kruban is a mythological paradise in which honourable warriors feast on the internal organs of their enemies.

Vaul is an ancient deity with myriad eyes and ears, who stood watch for enemies of his pantheon.

Uzin is a krogan god of vengeance (one of many).

Ancient Tuchankan legends claim that the Aralakh Wastes, named after the home system’s star, are where the first krogan warrior died in battle. Aralakh Company is made up of krogan from all over Tuchanka, each chosen for their strength, ferocity, and fighting experience. No krogan community would dream of sending anything less than its finest warriors to represent their clan. The honour of who’s to be chosen for the company has started more than a few brawls.

Krogan War Knife

The Krolirchim is one of the oldest known krogan texts, it's still read by warlords and battlemasters alike, containing as it does an epic telling of the battle of Janoran from before the nuclear conflicts on Tuchanka. It was written by Worend Rhakol, a legendary Battlemaster, and also contains discussions of tactics, philosophy and some poems written by Rhakol himself.

Of course, in a post-Reapers galaxy it's not all war and battle all the time. Some krogan are exploring new fads like the colourful Krodazzling.



Hadrash-Marg Class Freighter




Krogan Rebellions

The Genophage

The salarians believed the genophage would be used as a powerful deterrent, a position the turians viewed as naïve. Once the project was complete, the turians mass-produced and deployed it. The krogan homeworld, their colonies, and all occupied worlds were infected.

The genophage’s modus operandi wasn’t to reduce the fertility of krogan females, but rather the probability of viable pregnancies: many krogan died in stillbirth, with most fetuses never even reaching this stage of development. Moreover, every cell in each krogan was infected, to prevent the use of gene therapy to counteract it. Though the genophage wasn’t designed as a “sterility plague”, the combination of a low frequency of viable pregnancies with the krogan proclivity to violence (and indifference about focused breeding) left the krogan a dying race.

Without hundreds of krogan offspring being produced at a time, they couldn’t hope to stand against the turians. A female warlord, Shiagur, actually used her rare fertility to draw the strongest males to her band, but even she couldn’t hold out against turian peacekeeping forces, who finally killed her at the Battle of Canrum. In retaliation, many of the turians responsible were hunted down and killed by vengeful krogan males. Finally, besieged on all sides and knowing the survival of their species was at stake, the krogan surrendered. That wasn’t the end of hostilities, as many rogue warlords and insurgents refused to surrender, and had to be wiped out by turian task forces. Some even vanished into frontier systems to become pirates.


See: Tuchanka in the Reaper War

Post-War History

Retrospective 1

Retrospective 2

See Also

Threads of Interest

Krogan Venting Thread: The krogan of CDN air their frustrations about how their race is viewed by the galaxy.

Propaganda: Krogan are very to the point.

Vote For Mister Tuchanka 2192: A poll of the board's male krogan; who's the sexiest?

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