Time line follows the cannon lore of fallout timeline until the end
30th millenium begins: the empres makes herself known from the fallout of the old world and starts guiding the remains of the civilization into a new age. Blastech acceleration corp is founded and begins their research on advanced plasma and laser weapon technology.
Mid 30th millenium: the matriarch project begins, the empres also detonates the atomic beautification bomb on terra turning all women into amazons where the smallest stands at an astonishing 8 feet in height and the tallest can be up towards 9'5 unaltered. The first prototype of the plasma accelerator rifle is succesfully produced after several failed attempt.
31th millenium Begins: the matriarch project comes to fruition but the matriarchs are scattered by the great four entities that resides in the warp to stop the empres dreams. For a full year the empres just walks in a catatonic state grieving the loss of her daughters. After the year has passed she gets herself together and launches the great crusade.
The millenium passes and the matriarchs are found one by one.
32nd millenium: first encounter with the violent orks happens and the imperium starts preparing for the constant inevitable clashes with the greenskinned xenos race. During the middle of this millenium the imperium of mankind encounters the xenos race of eldar. Tensions runs high and another war begins causing more empasis on the development of their war technology.
33rd millenium: a new brand of power armour is developt by the forge world of Antioc at the peak of the millenium. This power armor combines the armor and protection of the catapracthii armor with the manouverability of the power armour mark VII aquila pattern. At the end of the millenium the great wedding is held where most of the matrairchs joins their husbands in holy matrimony.
34th millenium: the children of the matriarchs are born one by one giving birth to new primarchs and matriarchs. The tyranids arrive at the milky way causing another enemy for the empire to appear. The blastech acceleration corp perfects the technology of the plasma and laser handheld weapon technology giving the army and navy of the imperium unparralled fire power. The imperium starts to push back against the xenos that is the tyranid terror.
35th millenium: first waargh happens, the imperial guard suffers heavy losses due to the guard regiments being spread thin and unable to respond. The astartes legions muster a counter-attack against the ork lead by Garmag darkhand. The astartes and the orks clash and the first waargh is succesfully beaten.
36th millenium: the imperium develops a new space warp jump engine, removing the need for the old warp jumps and the need of navigators in the imperium. The navigator houses rebell causing a enormous civil war, the unsafe usage of warp powers by the rebelling navigator houses causes the fabric between the materium and inmaterium to split causing daemons to spill into the material realm.
37th millenium to 41th: the long war begins and continous to rage. John shepard is born to simelia el johnson, daughter of lionessa el johnson at the end of the 41th millenium. John due to being male is born as a normal human and his grandmother refuses to let him enlist into the imperial guard. Sneaking away with a transport shuttle he enlists and joins the imperial guard. First contact with the citadel races happen while john is a teenager and the first contact war happens. The citadel races is soundly defeated by the imperial guard due to the imperiums extremely advanced races. John's father is killed as one of the few casualties that the imperium suffers due to turian's laying a ambush and bombarbing the valley they were in laying in a valley on dark reach by being crushed by boulders. Ever since then Lionessa el johnsson has had a burning hatred for the citadel races due to the death of her son-in-law.
42th millenium: the imperium and the citadel races enters a delicate and fragile cease-fire. The citadel tries to enforce their laws upon the imperium to remove the imperiums advantage after seeing the devastating firepower that the imperium has over them. By this time john is promoted to commander and has finished the N7 program training and its discovered he is a true pariah and due to a genetic mutation it was discovered that he was a biotic, due to being exposed to the eezo at a mature age however, John's biotics was miniscule in powers. John single handedly handles the invasion of batarians due the skyllian blitz and earns the medal of valour for his efforts.