That's the biggest thing about the series that bugs me. How seriously fucked up the whole timeline for humanity is. The fact that we went from just opening our first relays to having multiple colonies and getting on the council in a matter of decades is just... ugh.
I don't even understand why they wanted that accelerated timeline instead of having it be 100 or 200 years after first contact.
It's a colossal oversight by the writers, especially Drew and co, how nobody from the very start noticed or cared that ~40 years is a ludicrously illogical window for humanity to have expanded to and populated hundreds of colonies, alien owned corporations, Citadel presence, and so on. It's right there at the start of the first game and it's super dumb in a series that's already ripe with a lot of super dumb.
So I would assume this would be another yahg situation, where they add an alien that we hadn't seen but apparently was around.
No, an space faring alien civilisation that simply hadn't reached citadel space by the time Mass Effect trilogy had started and met its conclusion. Imagine the Mass Effect galaxy, our galaxy, like a gigantic web network of relays. There's thousands, linked to various stars and systems, potentially habitable planets, yet only a very small percentage have been activated. Most of the galaxy is unexplored.
It took sixty years for the Asari to meet the Salarians. Five hundred years for those to meet the Rachni. Another five hundred before the Turians came into the picture. And so on. The idea is that somewhere in the galaxy, in these pockets of unexplored "known" space, a species evolved just like the rest, socially politically and technologically. They became a space faring species, likely discovered mass technology too, and started populating nearby planets like everybody else did once upon a time. Activated their first relay, which sent them to an empty system, explored that, and so on and so forth. They're doing all this shit, like everyone else did during their era, over a ~100 year period maybe a little bit more. Meanwhile the rest of the galaxy is doing their thing, trying to stop the Reapers. War is over, suddenly you bump into a species that's all "hey, what's up" because from their perspective they're just a fresh new space faring species making first contact with a bunch of other species. Kind of like how humans made first contact rather oblivious to the fact that for the last 2000 years the species they made contact with had suffered at least two major wars: Rachni and Krogan.
Said new species would be totally new in the strictest sense. A new species that simply hadn't made first contact, because they evolved in a part of the galaxy that had never been explored or seen.
Personally, I liked the idea that somebody proposed a while back about encountering a new advanced species that developed without Mass technology.
Technically, all the known races have had their technological development guided by mass tech because they've had exposure. What about a race that didn't have that leg up and had to develop their own?
Suddenly you could have a threat that isn't bound by the known rules and limitations.
Twas mine, and yeah, I think it's neat as it's a nice play on the whole "mass effect" theme while introducing its own cool new ideas. A simple oversight by the Reapers setting up all those relays and guiding technological evolution. They once upon a time (or the Leviathans I should say) started from scratch, so now you'd have a new species that did the same thing.
IIRC, it was something about making it more relatable to players, because they intended to have it set 100 years later than it was (that's why Pressley mentions his grandpa fought in the First Contact War in ME1, even though Pressley is old enough to have fought in it himself).
Didn't know that. So dumb. They should have just run with it. The short time period is enforced in the books too though. Anderson was alive and working in the military when humans made first contact.