"Exiles" is a blanket term for those Milky Way colonists who exist outside the authority of the Andromeda Initiative, either forced out as punishment or having willingly abandoned it of their own volition. Various factions have since coalesced over mutual goals, primarily survival in a hostile, foreign galaxy: Outlaws are militant exiles who prefer to solve problems with violence. The majority of the krogan contingent left the Nexus to settle the Heleus Cluster on their own, though a number of them joined the other factions.
Officially, no formal contact exists between the Nexus and the various Exile factions. In the eyes of the Nexus leadership, all Exiles are considered untrustworthy criminals, no matter their reasons for leaving or the context in which it occurred. Discreet ties are still maintained by people on both sides, however, facilitating a gray market of goods and intelligence and ensuring news still crosses ideological borders. Beyond the immediate jurisdiction of the station, Initiative personnel have collaborated with Exiles on numerous occasions.
Exiles eke out a living on whatever worlds they find themselves on, as scavengers, pirates, smugglers, independent homesteaders, wildcat miners and more. Following Pathfinder Ryder's successes in making the cluster more livable, some exiles have started returning to the Initiative's fold to give it a second chance.
The Nexus arrived in Andromeda under catastrophic circumstances: the station collided with the Scourge, resulting in extensive damage and significant casualties, most notably the Initiative's upper leadership. When it was verified that Initiative founder Jien Garson was among the dead, Directorship fell to the eighth person in succession, Jarun Tann, a deputy financial director with no charisma nor competence in fields other than his own.
Efforts to restore the Nexus were made under Tann, security director Sloane Kelly, superintendent Nakmor Kesh, colonial director Foster Addison, and engineer Calix Corvannis, though their efforts were continually hobbled by persistent supply shortfalls that could only be remedied by a steady flow of resources from planetside outposts. However, surveys of the golden worlds turned up bust, as all of them changed during the 600-year voyage and none were found viable for long-term settlement. Two attempts were made to colonize Eos—Site 1: Promise and Site 2: Resilience—but the high levels of radiation and attacks by hostile kett resulted in their abandonment.
The specialists brought out of cryo to fix the station were stressed and demoralized from the outset, but leadership decisions to censor vital developments and impose rationing slowly fomented the seeds of rebellion. With no help nor outposts forthcoming, after weeks of nonstop toil Tann's call to put people back in stasis to conserve supplies proved to be the tipping point as Calix incited his followers to disobey. His movement picked up steam, forcing Tann, Addison, and Addison's assistant William Spender to use the krogan to deal with it.
The krogan ended the uprising on a violent but decisive note, resulting in numerous deaths, including Calix. Sloane was against unleashing the krogan for this very reason, but she was elsewhere and wasn't consulted when the decision was made, leaving her no choice but to defect to the rebels to represent their grievances in the aftermath of Calix's demise. When Tann gave them an ultimatum—stasis or exile—Sloane and the other mutineers chose exile, preferring to take their chances off the station than put their lives under untrustworthy leaders.
Sloane and others exiles left the Nexus with some supplies but when it ran out, they were force to hit kett shipments and trade with angaran villages. They didn't get violent with angaran except for the Roekaar. Eventually, Sloane learned about Kadara Port, an old angaran port occupied by the kett.
Sloane's faction, eventually named the Outcasts, arrived on Kadara, where they forced out the kett occupiers of Kadara Port and earned the gratitude of the local angara. They developed a powerbase there, offering protection and a place to stay, provided one can keep up with the fees. People who found Sloane's rule too chafing often joined rival groups such as the Collective, or ended up on Elaaden, an even worse hellhole than sulfurous Kadara, where scavenging and violence was the norm rather than the exception.
Nakmor Morda, leader of the krogan, was promised a seat on the Nexus council by Spender in exchange for putting down the uprising. However, Spender neglected to tell Tann of this, whose anti-krogan racism emerged in full view when he learned of it and consequently refused to honor the deal. Morda was barely talked out of declaring war with the Nexus by Kesh, who proposed the krogan also follow the exiles while she stayed to make sure they were still represented. They ended up establishing New Tuchanka on Elaaden.
Exiles were the unacknowledged actual first contact point between the Milky Way races and the angara: by the time Ryder landed on Aya for official first contact, the angara were already aware of the extragalactic visitors enough to be conversant in their language.
Exiles have hybridized Heleus and Initiative technologies in order to adapt to the harsh environments of the cluster. The results are often surprisingly effective.