User blog comment:GruffMuff/How did the Reapers invade the galaxy in Mass Effect 3?/@comment-1596833-20111120022704

I'm guessing that the Reapers have originally had multiple relays other than the Alpha and the Citadel, but it's more than likely the majority have been taken out, either by species one hundred percent unaware of the reapers, just killing each other off, or by species who did know the truth(Perhaps Prothean remants), the only thing I have o say is that Mass Effect 3 takes place after ME2 by several months to a year.