5 mysteries we want to see unraveled in Mass Effect 4

person at a spacesuit aiming at a large alien in the background. a star rises above the scene
Mass Effect 4 has been announced, but what is in it remains a big mystery. (Image credit: Bioware)

It's time to go deep-space scouting in the Normandy again as we run down the top Mass Effect mysteries that we hope to see explained in Mass Effect 4.

In late 2022, Mass Effect trilogy fans were treated to a special announcement: maker Bioware said it is still going forward on Mass Effect 4 after its 2020 promise to start development. The company even released a short teaser trailer. There's no release date yet, but that gives time to play through the original trilogy (yet again) if you want.

Mass Effect was first released between 2007 and and 2012, and rereleased as Mass Effect: Legendary Edition in 2021. The trilogy (known as ME1, ME2 and ME3 to fans) was close to the new "Star Trek" or "Star Wars" that we desperately wanted when both of those franchises were in a lull. 

In Mass Effect, a rich universe of beings were working together to address intergalactic conflicts, led by a female or male Commander Shepard. Actions taken throughout the game, as a paragon or renegade, influenced events throughout the game as well. We loved the trilogy so much that we put it into our list of the best space games ever made. Bioware also released Mass Effect: Andromeda in 2017, but let's just say that most fans didn't find it nearly as compelling.

The new Mass Effect, we are hoping, will feature better controls for the Mako ground vehicle, more genders and races for your commander, deeper lore for the aliens and planets, and other quality of life improvements. But what about the plot points of Mass Effect?

Leaving aside ME3's controversial ending in which we learned our actions in the trilogy had little effect on the outcome, here are some of the biggest unanswered questions we'd like to see in the sequel. Spoiler alert: Big plot points are revealed ahead.

Related: Upcoming space games: Starfield, Star Wars Jedi Survivor, Mass Effect 4 & more

1. Dark Energy

Mass Effect spacecraft used relays for transportation. The relays are one manifestation of mysterious dark energy in the Mass Effect canon. (Image credit: Bioware/Mass Effect Continuation Wiki)

Dark energy in the Mass Effect universe is somewhat akin to what we think we know about the real-life science phenomenon. Simply put, the universe is accelerating in its expansion and why is poorly understood. Physicists suggest that dark energy along with dark matter may be ballooning our cosmos, but how is a big debate.

Mass Effect's dark energy uses element zero, a rare material in the canon, to manipulate dark energy. Extreme electrical currents release dark energy in the element, allowing for faster-than-light (FTL) travel along with advancements in technology and manufacturing in the fictional universe. 

ME2 however, introduced some notions about dark energy that the plot writers ultimately decided to drop in ME3 due to complication. Fans suggest that the implications of ME2's discussion is huge: perhaps using dark energy leads to destroying societies over time. Does this lead to the cycle of Reapers performing genocides, in era after era? Or is there something more to it?

2. The fate of the Citadel

The Citadel of Mass Effect under attack from a Reaper. (Image credit: Bioware)

The end game of ME3 is, well, complicated. So complicated that you may have missed one of the major plot holes: what happened to the Citadel after the Reapers took control of it. Given several million beings from numerous species live on board, it's no small question.

Bioware sort of addressed this in a 2019 YouTube update with Ars Technica. They suggested that the Reapers just left the beings to live for now, with the understanding that once the war slowed down a bit that they would turn everybody into zombie-like husks.

Assuming that notion did make it into canon, and then what? Now we have millions of extra zombies on board this space station? That doesn't sound good.

3. Was Shepard indoctrinated?

An Indoctrinated Saren about to shoot Nihlus in the back of the head in Mass Effect. (Image credit: EA)

Indoctrination is how the Reapers take control of beings in the game, most notoriously Saren in ME1. Apparently the Reapers can generate some sort of signal or energy field that warps the minds of anybody who gets within their range. Reaper artifacts may also be prone to this issue, like what the hapless MSV Concordia encountered when they brought one on board.

Some fans are wondering if Commander Shepard (male or female in the original trilogy) is indoctrinated themselves, in a way that is very gradual but explainable by coming into constant contact with Reaper tech. If that's indeed the case, this may explain some of the trouble surrounding the ME3 ending as you could explain the events by a dream scenario, meaning Shepard was experiencing it all in their head.

ME3 writer Chris Hepler, who spoke with TheGamer about this in 2021, said this idea wasn't intended by the writers. But he also called it a reasonable interpretation by gamers. Will ME4 pick up the plot thread and run with it? If so, can they explain in more detail how indoctrination works and how to counteract it? That would really help fans trying to figure out why different beings have different reactions to it.

4. What was ExoGeni's real agenda?

The ExoGeni Corp studied beings like the Thorian with less than ideal morals at play. (Image credit: EA)

ExoGeni Corp. is a company with pretty terrible morals. Framed as a firm that focuses on interstellar exploration and mining, but the company treats its employees badly: causing mental health issues and failing to provide medical treatment, exploiting harmless aliens for profit and forcing settlers to give over Prothean finds as a form of funding their new homes.

After ME1, we don't hear much about the company's current activities beyond what happened after their actions pretty much caused the death of a unique being known as the Thorian. We do know they left the area, and took the Thorian with them, but their plans after these terrible events were never revealed.

Getting that plot point wrapped up would be great for curious fans, although at the same time, we acknowledge their actions are rather unsettling. But given ExoGeni is frequently referenced in the games, some closure would be helpful.

5. Who were the Keepers before they were enslaved?

One of the enigmatic Keepers who care for the Citadel. (Image credit: EA)

The Keepers are one of the cutest "fetch quests" of the trilogy. In ME1, Shepard is tasked with scanning the Keepers to find out more about these quiet keepers of the Citadel. We don't find much more even after completing the quest, however, leading to some questions about their origins.

It was believed the Protheans created the Keepers solely for keeping up Citadel maintenance (though we later find out they were in fact a race that was enslaved by the Reapers). It is forbidden for anyone to interact with the Keepers and they are very much focused on their tasks in any case.

They were likely a race in one of the early cycles of galactic harvesting that the reapers oversaw, who were enslaved instead of being wiped out (much like the Collectors). But who were they? And why did the reapers choose to indoctrinate them instead of melting them down and pouring the goo into another Reaper?

Unfortunately, since the Reapers took control of the Citadel in ME3, getting more information from the Keepers might be difficult. Maybe we'll be able to break in during ME4 and help the Keepers, learning more in the process.

Elizabeth Howell is the co-author of "Why Am I Taller?" (ECW Press, 2022; with Canadian astronaut Dave Williams), a book about space medicine. Follow her on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for Space.com for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: https://qoto.org/@howellspace

  • kspyder00
    Did the author ever actually play the games? Neither the keepers or the relays were created by the protheans, and calling the thorian an "harmless being" is ridiculous.
  • Dizzy-1
    kspyder00 said:
    Did the author ever actually play the games? Neither the keepers or the relays were created by the protheans, and calling the thorian an "harmless being" is ridiculous.
    Definitely not.... a picture of Garrus labeled as Saren.... I lose more and more respect for this site every time I read an article
  • Ian Stokes
    Editor here - Sorry, that image label was my fault (and no idea how I messed that up, Garrus is my boy)

    As to the factual inaccuracies, thanks for pointing them out. The writer has indeed played the games, they recently blasted through the whole trilogy and have been talking my ear off about it. It's a dense series and there is a lot going on in the plot, so I can't blame them for missing a beat here or there, but I should have caught it in the edits, so apologies.

    The article has been updated
  • RDiddy
    What about mass effect Andromeda? Thats the 4th instalment.
  • Ian Stokes
    Eh, it's a spin-off which I wouldn't put in the mainline series. Think Fallout 3 - Fallout New Vegas - Fallout 4.

    There isn't really any consensus on what we're calling it until we get a proper title from Bioware. Some sites are going with 4, some with 5. I'd rather forget about Andromeda, so 4 for us haha.