Saren's Alliance 2155 CE - 2183 CE
Saren's Alliance at its greatest extent in 2183 CE.
Political information
Type of government:	Military alliance
Founding document:	Geth Schism
Head of State:	Sovereign (first and last)
Commander-in-chief:	Saren Arterius (first and last)
Military:	Geth Heretic Forces Droya's tank-bred krogan 23rd Commando Company
Societal information
Capital:	Virmire Heretic Fortress, Virmire
Official language:	None
Currency:	Credit
Official religion:	Awe of the Reapers
Historical information
Formed from:	Geth Heretics Sovereign Saren Arterius
Dates:	27 February 2155 CE - 19 July 2183 CE (28 years, 4 months and 22 days)

"I'm forging an alliance between us and the Reapers, between organics and machines. And in doing so I will have saved more lives than have ever existed!"

— Saren Arterius to Marcus L. Shepard in the closing minutes of the Battle of Virmire.

Saren's Alliance, also known as Saren's Army, was a military alliance between numerous entities organized and formed by the rogue spectre Saren Arterius at the behest of the Reaper Sovereign, with the ultimate goal of bringing about the return of the Reapers and resuming their galactic cycle of genocide. The origins of the alliance stem from the intertwined actions of both Sovereign and Saren Arterius: Sovereign, having been left behind after the prothean cycle to act as the vanguard of the next Reaper invasion, awoke over several periods from 1080 BCE to 1760 CE to check on the status of the galaxy. Finally, it concluded that in 1830 CE the harvest was ready to continue, but when it went the signal to the Citadel for the Keepers to activate the relay so the Reapers could pore through, the signal went ignored and Sovereign was left to try and figure out what went wrong: over the next century, Sovereign used indoctrinated agents it had acquired to figure out what had gone wrong, and ultimately concluded the keepers had been tampered with somehow. Realizing it would need direct access to the Citadel in order to bypass the keepers and manually begin the invasion, but knowing that exposing itself too soon could cause the galaxy to unite against it, it spent the next couple of centuries in hiding, maintaining a shroud of secrecy as it investigated possible options. In 2155 CE, Sovereign entered the Perseus Veil and approached Rannoch, where it entered into talks with the geth to enlist them in its cause to bring about the harvest, offering to exchange technology and to upgrade the geth with Reaper code so they can ascend to true AI status: while the majority of geth viewed the Reapers ("Old Machines" as they called them) as holding views they did not agree with, and they would prefer to develop along their own path, a minority of the geth viewed the Reapers as gods and the pinnacle of synthetic evolution, worshipping Sovereign as "the Herald" and wishing to help the Reapers "ascend" the inferior organics, especially if it helped their creators ascend, as well as accepting the gifts the Reapers offered. This group became known as the Geth Heretics, and this disagreement over whether or not to join Sovereign led to a brief, "bloodless" schism that ended with the rest of the geth allowing the geth heretics to leave with Sovereign, but banishing them from geth space never to return due to them embracing violence against their creators. This gave Sovereign access to his first army, with 2% of the geth population joining him (providing a billion troops) and hundreds of warships. A base of operations is established on Virmire, and by 2162 CE the Virmire Heretic Fortress is built to provide a heavily fortified but obscure location for Sovereign to lay low when not conducting operations.

In 2165 CE, Saren Arterius concluded a mission on Camala where he gained access to a Reaper artifact (he was not aware of this at the time) from a dead Alliance scientist, believing he could use it to gain control of the geth and use them to bring humanity to their knees, forcing them to learn their place in the galaxy. When he learned about a volus freighter transporting what he believed to be another one of the artifacts, he hired Urdnot Wrex and several other mercenaries to raid the freighter: when he found nothing of note on it, he had the mercenaries killed, although Urdnot Wrex was able to escape when he grew suspicious and left without getting paid, leaving Saren without a paper trail to track him down. Through Saren's use of the artifact, Sovereign learns of Saren's motives and concludes that a spectre has the necessary resources and willpower to achieve what Sovereign needs and do it with absolute secrecy, and this, coupled with Saren's excellent track record and reputation, leads Sovereign to confront Saren, introducing itself to the turian and telling Saren about the galactic harvest, and that Saren will be his emissary for organics and their only chance to prove their usefulness to the Reapers in order to avoid extinction. This is of course a ruse to entice Saren into joining him, with Sovereign's indoctrination leaving Saren oblivious to the Reaper's true intentions. With Saren's enlistment into Sovereign's cause, and Sovereign becoming Saren's flagship, the alliance is born.

Saren's Alliance continued to grow throughout the years as Saren used his network of contacts and his Spectre resources to search for prothean artifacts, gather allies, and build an army. At some point, Sovereign pieced together how the protheans were able to alter the Keepers to ignore the signal, and that they usedan object known as the Conduit to gain access to the Citadel to make the modifications: with this knowledge in mind, he makes it Saren's mission to find it. As this happens the alliance continues to expand: Matriarch Benezia M'Soni and the attached 23rd Commando Company fell under Sovereign's sway when Benezia attempted to save Saren from his current course, ultimately becoming his second-in-command and most valuable asset, while her commandos became willing servants of Saren due to their indoctrination. Realizing he could control the krogan and get them to join his army if he created a cure for the genophage, Saren enlisted Dr. Quiath Droya, a krogan scientist, to begin work on a cure and gave him a state-of-the-art laboratory on Virmire to conduct his research, and this later led to Droya creating tank-bred krogan, grown in birthing vats, for Saren's army, giving him access to legions of mindless krogan shock troops as well. Using Saren's investment in Binary Helix, Sovereign directed them to a derelict rachni ship that was leftover from the Rachni Wars, carrying an egg containing the last survivor of the rachni species, a queen: this was done so that Binary Helix would hatch the queen and use her to begin breeding a rachni army for use by Saren's forces, hoping that the rachni could be raised independent of the queen and then implanted with control chips so that they only responded to Sovereign's directions, not the queen's. Many intelligence resources were used as well to begin scouring the galaxy for clues as to the location of the Conduit, and it was eventually concluded that working prothean beacons would be needed to find the Conduit's location. While one had already been found on Virmire, which is why the planet was initially chosen in the first place, the images burned into Saren's minds were jumbled and confused, and they realized that the images were not only incomplete, and that another beacon contained the rest, but that an understanding of prothean language would be needed to even decipher the images and understand them. Saren's search continued, finally bearing fruit in 2183 CE when he read Council reports that a prothean beacon had been unearthed on Eden Prime by the Alliance. Knowing that an Alliance warship was en route to retrieve the beacon and transport it to a more secure site, Saren seized the opportunity and left with Sovereign and a geth invasion force to attack Eden Prime and gain access to the beacon by force. This attack was the beginning of the Eden Prime War, and saw Saren successfully gain access to the beacon and completing the vision already present in his mind. He attempted to have the beacon destroyed to deny enemy access to it, but an N7 operative that arrived on site managed to have part of the vision burned into his brain as well.

While Saren's Alliance faced numerous defeats and setbacks throughout the Eden Prime War as it progressed, among them being the loss of his spectre status, the defeat of a geth heretic invasion in the Armstrong cluster, the lloss of his rachni army and death of Benezia on Noveria and the nuclear destruction of the Virmire fortress, Saren's Alliance was able to remain one step ahead of Shepard and the Alliance throughout the conflict, and came very close to victory in the war. Saren gained access to the cipher through the Thorian on Feros, and while his attempt to have it killed and deny the cipher to Shepard ultimately failed, he now had the knowledge that the Conduit was on Ilos, and through this, also learned that the rachni queen knew the location of the Mu Relay, the only way to access the planet. By the time Shepard also caught up on this and learned about Ilos, Saren and his forces had already landed on the planet and Sovereign and the geth fleet began its assault on the Citadel. However, thanks to a last minute mutiny by Shepard and his crew, they were able to track down Saren and follow him through the Conduit, with Shepard successfully managing to persuade Saren of his indoctrination, leading to the rogue spectre's suicide. This, coupled with the arrival of the Fifth Fleet as reinforcements during the battle, saw the destruction of the geth fleet, and through further battle, the destruction of Sovereign as well. With Saren and Benezia dead, Sovereign destroyed, the Virmire fortress wiped out, Dr. Quiath Droya dead and his cloning facilities gone with him and the rachni queen freed from captivity, only the remnants of the geth heretics were left and Saren's Alliance subsequently collapsed. The geth heretics would continue to resist organics for the years following, becoming raiders and launching the occasional attack, but any coordinated leadership on their part was over, and in 2185 CE, a virus was distributed throughout their consensus that reprogrammed them to reject the Reapers' logic and return to the true geth, causing them to disband and finally ending the last of Sovereign's followers.