Before there was history, there were the Protheans.
The Protheans were an ancient race of beings that vanished from the Perseus Arm of the galaxy 50,000 years ago. However, they did not disappear without a trace.
The Protheans left behind a series of relics and artifacts for the galaxy’s future beings to discover.
When a race finally achieved space travel proficiency and discovered a marker left behind by the Protheans, they were directed to a mass relay—a piece of alien technology that allows faster-than-light travel.
Over the eons, more and more races evolved and expanded, eventually discovering what is believed to be Prothean technology.
When they followed the trail left behind by the ancients, they rocketed to the Citadel in the Serpent Nebula. The Citadel is a massive space station, a wonder of technology that managed to survive while the Protheans themselves did not.
As more races reached the Citadel, it became the central hub of government and order in the Perseus Arm.
Humans found their first Prothean beacon on Mars. This directed them to a mass relay that allowed them to become the newest member of the galactic community.
The galaxy was not exactly happy to see humankind, though. Humans developed a reputation for arrogance and aggression because they did not merely accept their lowly station as newcomers.
Though the Council that oversees all order in the galaxy did indeed welcome the humans, skepticism of humankind reached all the way to the top.
But now the galaxy owes a debt to humanity and, more importantly, to Commander Shepard.
The commander is almost single-handedly responsible for unraveling a tapestry of deceit that would have led to the destruction not just of humankind, but of all life in the galaxy.
A rogue Spectre named Saren, an agent of the ruling Council, commandeered an army of artificial beings called geth to annihilate the Citadel.
The geth were created over 300 years ago by the quarians as laborers, but they rose up against their masters.
A long, costly war between the geth and quarians resulted in the eventual banishment of the geth to a sector of the galaxy beyond the Perseus Veil. But a dark nebula of opaque gas obscured the actions of the geth.
Why would Saren turn on the Council he was sworn to protect? Saren knew of the Reapers, an ancient race of beings that are hell-bent on wiping out all organic life—like they had done once before with the Protheans.
And a race before them. And before them. In fact, the Reapers have been repeating a cycle of allowing life in the galaxy to evolve to a certain point and then crushing it again.
The Citadel is just a tool of the Reapers’ wicked plans.
Saren hoped that by helping the Reapers, he would be spared the inevitable. But he was tragically wrong.
A powerful Reaper called Sovereign was revealed to be controlling Saren, using the former Spectre to gain access to the Conduit so the Reapers could take over the Citadel and its citizens.
Defying the Council, which refused to believe Shepard’s findings about the Reapers, Shepard raced to the Conduit to stop Sovereign.
Through skill and sacrifice, Shepard and his crew were able to stop Sovereign from taking the Citadel and destroying all life in the galaxy.
As a result of Shepard’s heroism, the Council recognized the worth of humanity. The human race was accepted into the Council and began the next chapter in its seemingly unending ascension.
But Sovereign was only one of the Reapers. They are on the march again.
And they have employed the services of a mysterious alien race called the Collectors.