Mass effect and its characters, story lines etc belong to Bioware blah blah blah.
Ok so this is a idea that's been sitting in my head ever since I played ME2 the first time, although I've developed it quite a bit more recently. Ashley's reaction on Horizon never entirely felt right and then they dragged it out a bit in ME3, so her involvement in the collector mission is the primary change here. I'm also going to expand the ground team with a couple of other characters (one completely new one altered, neither will be Shepard's sister) that should bring more conflict to the operation and provide a bit more variety to the possible scenarios the team encounters.
As far as the story goes the main plot is primarily unchanged but I will change some things to bring a greater sense of believability to certain elements of the story. The shadow broker and arrival dlc will be incorporated in what will hopefully be a more cohesive fashion, probably won't write a variation on operation overlord but might reference it. The recruitment and loyalty missions will be different at varying degrees.
The story itself will cut in and out a bit until Horizon but there are some bits that just need to be included and one or two others that just feel like too much fun.
First things first the background and ME1 choices need to be covered so let's get started.
Shepard's background
Shepard qualifies as a Sentinel, with an significant shield upgrade and an overload function for the tech side, and a powerful warp and throw for his biotics. However he is good with more conventional combat as well, preferring to carry a sniper rifle in addition to his shotgun and sidearm.
He is a paragon with a renegade streak.
Have a mixed background here so bear with me. Both he and his sister Jane were born on Earth but raised on Mindoir until the slaver attack that killed Shepards father when he was thirteen, he and Jane(who was twelve) were the only survivors left in their settlement. They were then raised by their mother on various ship postings until they both enlist (separately).
John, a 1st lieutenant fresh out of officer training, is on Elysium for the Skyllian Blitz, awarded the Star of Terra for his work there and then applies for N7 training. Jane, fresh out of basic training is on Akuze and is the only recorded survivor of the thresher maw attack, the alliance picks up on this and uses the siblings miraculous survivals for PR benefit already making them minor celebrities. Jane doesn't follow her brother into the N7 program but does go through officer training.
ME1
Wrex Killed Fist.
Saved colonists on Feros, got Cipher from Shiala who stayed to help Feros.
Helped Emily Wong also gave incriminating evidence on the criminal activities of Exo Geni and Binary Helix (minus Rachni Data).
Saved Rachni Queen.
Romanced Ashley and saved her on Virmire (obviously).
Talked down Wrex, saved Kirrahe and spared Rana Thanoptis on Virmire.
Saved Terra Nova from Balak.
Shut down rogue VI on Luna.
Talked biotic cultist leader Major Kyle into surrendering.
Talked down Toombs by relating to him through Jane.
Exposes Cerberus' crimes with evidence from Edolus, Binthu, Nepheron and Chasca as well as the testimony from Toombs and Dr. Wayne.
Helped Garrus with Dr. Saleon, Wrex with his families armour and Tali with her pilgrimage gift.
Cleared out the Geth staging points in the Armstrong cluster.
Convinced Saren he was Indoctrinated so he killed himself.
Saved the Citadel council.
Recommended Anderson as Human councilor.
Staff Commander John Shepard is promoted to Captain after the Battle of the Citadel, in response to his pivotal actions there, as well as the irregularity of having a Commander as CO of the Alliance's most advanced frigate. He also receives numerous commendations from the alliance for saving Eden Prime, Feros and Terra Nova, as well as an honourary award from the Asari for saving Councilor Tevos and the Destiny Ascension.
Gunnery Chief Williams (on Shepards recommendation) is promoted to Operations Chief and offered Officer Training, she accepts and by the time she arrives on Horizon she has just achieved the rank of Staff Lieutenant.
Staff Lieutenant Jane Shepard was assigned to the SSV Dunkirk during the Battle of the Citadel. Early in the engagement the frigate took some damage in which all weapons systems are disabled and the commanding officer is killed, consequentially the Lieutenant takes command. The younger Shepard notices the SSV Perugia sustaining heavy damage from Geth weapons fire, but manages to intervene by using the smaller Dunkirk to shield the cruiser from what would have been a fatal blow.
Whilst the action cost the lives of seven of her own crew it saved the lives of the much more heavily populated Perugia, earning her a promotion to Lieutenant Commander after the battle. Two more years of distinguished service earn her a promotion to Staff Commander and the position as the XO of the SSV Sydney.