Author's Note: I'm not usually one to do these, but I do believe it's appropriate here. I do not doubt that people will read this and be thinking "Who are these people?" or "This isn't the right date for Mass Effect" or "I'm confused". This story isn't canonical to the "actual" Mass Effect universe. If you have not read the Mechagodzilla series, the G-Chaser series, the Extended Universe (aka Halo Different) series or the Firefly Mk2 series then do so before reading this story. This series follows on from where the Firefly Mk2 series left off. The G-Chaser and Firefly Mk2 series can be found on my page, while the Mechagodzilla and Extended Universe series can be found on CII's page (she is listed under my favourite authors). Those stories should answer all of your questions. If you're not going to take the time to read those stories then please don't waste my time with comments expressing confusion or complaints about characters or story elements that aren't in the Mass Effect timeline. These characters and story elements are established in CII's universe and I won't alter them.
This series is also based (however loosely) on my own personal play-through of the Mass Effect series. Neither CII nor myself own Mass Effect, Halo or anything else; just our own versions of them.
Prologue
In the year 2553, thirty years after it had begun, Earth's brutal war against the collection of alien races known as the Covenant ended. Humanity triumphed, thanks to the aid of their Sangheili allies, and began to rebuild its civilisation and all that was lost in the war. Chief among the reconstructions was the restoration of the planet Reach, which had supplied the United Nations Space Command with its largest shipyards.
Humanity would soon find that it was not alone, for six months after the war contact was established with the Citadel, the heart of galactic civilisation. Due to their efforts in the war, the alien Council granted humanity an embassy on the Citadel, with Kiryuu Knight and Donnel Udina elected as Earth's ambassadors. However the Sangheili rejected the offer of an embassy, unhappy with the stringent Treaty of Farixen and determined to maintain their independence after finally breaking free from the Covenant. In spite of this, the Sangheili remain steadfast allies of the humans, forming with them the Orion Alliance, charged with the safety of the Orion Arm.
Five years have passed, which have been spent rebuilding the strength of the UNSC armada, including the fitting of suitable slip-space drives to take advantage of the Mass Relay network. These incredible structures believed to be created by the Forerunners allow for instantaneous transportation between any two relays, even those at the far reaches of the galaxy. As a result humanity has expanded its colonies further than ever before, though some of the humans, unhappy with the Citadel's regulations, have settled out in the lawless Terminus Systems. Wherever they went, however, the people of Earth proved themselves to be adroit and adaptive – to the consternation of some longer-established species, who view the treatment of the humans as an act of favouritism.
All of galactic civilisation is built on the backs of the relays. At the heart of them lies a force capable of manipulating the fabric of space and time; a force which has led all into a prosperous new age.
The civilisations of the galaxy call this force Mass Effect.