All of the decisions and choices made in Mass Effect 1 and 2 have led to this. Mass Effect 3 marks the final showdown with the Reapers and if you’ve been gathering War Assets throughout the Legendary Edition, they’ll come into play at the end. Of course, you’ll have the opportunity to make even more impactful decisions throughout the third title – here are all of the big and small decisions along with their consequences.
Diana Allers – Diana is found in the Citadel during your first visit in Normandy Dock: Bay D24. You can choose to have her as an embedded journalist on the Normandy and she’ll also become a War Asset (though she can be told to leave whenever). Refusing her sees Diana going to the SSV Shasta and dying when the ship is later destroyed.
Virmire Survivor on Mars – You’ll meet the survivor of Virmire on Mars, which could be Kaidan or Ashley depending on your choice from Mass Effect 1. If you choose mostly Paragon options with them in your squad, then they’ll have a more positive outlook on Shepard. Go with Renegade options and they’ll be less trusting. Considering that Ashley/Kaiden becomes a Spectre and works under Udina (who betrays the Citadel to Cerberus), going Renegade means they could potentially die in that scenario.
Grissom Academy – The mission “Grissom Academy: Emergency Evacuation” becomes available after Thessia and sees Shepard reuniting with Jack. It can expire if you don’t complete it before “Priority: Citadel 2” so it’s advised to do it and gain Jack and her students as War Assets. You can also choose how to deploy them – send them to the frontlines and they’ll die. Keep them as support and they’ll live. Not completing the mission results in Jack being turned into a Cerberus Phantom and popping up in Cronos Station, where she must be killed. And no, her students don’t survive either.
Tuchanka – This mission culminates in trying to cure the Genophage by dispersing it through the Shroud on Tuchanka. However, you’re informed by the Salarians that the Shroud has been sabotaged. If you bring this up with the Krogans, then the cure will be dispersed as normal.
If Wrex is alive and you gained Maelon’s data in Mass Effect 2 (more info on that here), then the STG doctor present will try to fix the sabotage. You’re then given a choice to stop them, which results in weakened Krogan support and more Salarian support, or let them fix it, which results in Salarian support being lost completely. If Wrex died in Mass Effect 1 and Maelon’s data wasn’t saved, then the STG doctor can be persuaded to support the sabotage, thus ensuring Salarian and Krogan support (though the latter will be weaker than normal). Also, if Maelon’s data wasn’t saved, then Eve won’t survive the process.
Meeting Miranda – Miranda will appear at some point and can be a War Asset later on. First, make sure to read about Kai Leng in your private terminal and then warn her about him in your first conversation (especially if you didn’t gain her loyalty in Mass Effect 2). In the second conversation, give her access to Alliance Resources. If you romanced Miranda in the second game, then you can’t break it off. Fulfill all these steps and she’ll survive and become a War Asset. Fail and she’ll die.
Attican Traverse: Krogan Team – In the mission “Attican Traverse: Krogan Team”, you’ll encounter a Rachni leader. If you spared the Rachni Queen on Noveria in Mass Effect 1, then she’ll appear here, otherwise it’s a Rachni Breeder that’s been created by the Reapers. Sparing the Rachni Queen results in her joining the war effort. Killing the Rachni Queen in Mass Effect 1 and then helping the Rachni Breeder results in her betraying you and reducing the overall War Assets. You can also opt to kill the Rachni Queen or Breeder, which is highly advised in the latter’s case (you won’t gain any assets as a result but at least none will be lost either). It’s also worth noting that Grunt can join in on this mission but will die if you didn’t finish his loyalty mission in the previous game.
Kallini: Ardat-Yakshi Monastery – If kept Morinth alive in Mass Effect 2, then there will be a report about her in this mission. Otherwise, if you went with Samara, then she’ll play a big part. At the end, with Falere being present outside of the monastery, Samara will cite the Justicar code and, unable to kill her daughter, attempt to commit suicide. Stopping her with a Paragon prompt will see her joining as a War Asset while Falere stays at the monastery.
If Samara dies or isn’t present, then you can choose to leave Falere on the planet (where she promises she won’t be alive when the Reapers come) or kill her.
Priority: Rannoch – It’s imperative to save Admiral Koris in the “Rannoch: Admiral Koris” mission beforehand by using either Charm or Intimidate. Make sure you also complete the “Rannoch: Geth Fighter Squadrons” mission before doing Priority: Rannoch. Doing so will allow the fighters to be used and result in both Legion and Tali being alive. Failing to do this will result in either Tali and the Quarians dying if you allow the upload or Legion and the Geth dying if you stop the upload.
Kelly Chambers’ Identity – Kelly Chambers can be found in the Docks: Holding Area in the Citadel on your first visit, assuming she survived in Mass Effect 2. You can tell her to change her identity, which will be crucial when Cerberus attacks the Citadel since it will allow her to survive. When meeting her again, she’ll confess to spying on Shepard and the crew for the Illusive Man. If you say “It’s okay”, then Kelly will return Shepard’s fish from Mass Effect 2. If you choose to scold her, then she’ll ingest a cyanide pill later and kill herself.
Aria’s Speech and Petrovsky’s Fate (Omega DLC) – Depending on your actions in the Omega DLC, Aria’s attitude will be different and this will reflect in her speech. If you haven’t been consistently sticking to either Paragon or Renegade, you’ll receive two dialogue options: “You need to reform” and “I’ll leave you to guess.” The former is a Paragon choice while the latter is Renegade – both can directly affect the contents of her speech.
If you’ve been mostly Renegade during the mission, then Aria will kill General Petrovsky. The latter can be spared if you’re Paragon and even if Aria isn’t willing to do so, then there will be two Paragon interrupts that will make it possible. Aria won’t be very happy with the result so keep that in mind. If General Petrovsky is delivered to Shepard, then they can kill him with two Renegade interrupts.
Brooks’ Fate (Citadel DLC) – Once the final boss of the Citadel DLC has been dealt with, you have to determine what happens to Agent Brooks. If you go with the Paragon dialogue choice and Paragon interrupt, Brooks will accept her fate and not try to hack the cuffs to escape. Choose the Renegade dialogue choice and Brooks will hack through the cuffs to escape. You then have the option to shoot her with a Renegade prompt – this can also pop up if you don’t take the Paragon interrupt from earlier. If you don’t shoot Brooks, then a squad-mate will shoot her instead, bringing the story to a close.
Illusive Man Conversations
The Illusive Man is a key part of the finale but depending on the dialogue chosen in conversations throughout Mass Effect 3, you can help prevent Anderson’s death. You’ll speak to him on Mars, Thessia and Cronos Station prior to the Conduit on Earth. The key is to go with every Charm or Intimidate option possible in these conversations. Some will only be found by choosing “Investigate” so make sure to thoroughly explore each dialogue option.
If you successfully used all of the Charm options, then the dialogue “But you already have” will become available in the Conduit. This will convince the Illusive Man that he’s been indoctrinated, resulting in him committing suicide. Going with all of the Intimidate options will provide the dialogue option “Then you’ve failed humanity.” Choosing this causes the Illusive Man to push Anderson aside and aim for Shepard, which will provide a Renegade prompt. Use this to kill him – not doing so will result in Shepard’s death and having to redo the conversation.
If you didn’t use all of the Charm or Intimidate options in previous conversations, then you’ll only have two dialogue choices “You’re theirs now” and “You’re pathetic.” If you go with either, then the Illusive Man will make to kill Anderson. You’ll receive a Renegade prompt to kill him first – not taking it will result in Anderson dying. A second prompt will then come up to kill the Illusive Man. Failing to use it will result in Shepard dying and the conversation restarts.
If Anderson survives, then he’ll have one last talk with Shepard. If Anderson dies, then Shepard will look out at the Earth one last time before venturing forth.
Effective Military Strength and Endings
The ending will be determined by your War Assets and Effective Military Strength (EMS). With the Legendary Edition, all of your decisions made through the trilogy are taken into account so the overall figure will be slightly higher than in the base game. For more details on the various endings for each game, head here.
For the sake of simplicity, we’ll look at EMS requirements and outcomes from the original release. At less than 1,750 EMS (aka the lowest possible figure), only the Control and Destroy endings will be available, and the toll of these is very heavy. If you have 1750 to 2649 EMS (low-mid), then you’ll have the same ending choices but the Destroy ending is less brutal.
At 2650 to 2799 EMS (a medium amount of EMS in the Legendary Edition), the same two choices are available but neither will cause damage and the Normandy’s crew will survive. From 2800 to 3099 EMS (medium-high), you’ll have the Synthesis option along with Control and Destroy which results in little damage. At 3100 EMS or higher, which translates to 7800 or more in the Legendary Edition, you can choose any ending without major consequences and Shepard will be teased as alive in the end.