Mass Effect: Legendary Edition has different endings for each of its game, though the most diverse set can be found in Mass Effect 3. That being said, with the changes to Effective Military Strength and removal of multiplayer in the third game, your choices throughout the trilogy will have an even larger impact on the overall ending. Spoilers follow so beware.
Let’s start with Mass Effect 1. Like before, there is a Good and Bad ending based on whether you choose to save the Council, let the Council die or focus fire on Sovereign in the mission “Race Against Time: Final Battle.” Saving the Council will result in a human representative joining the group which also thanks Shepard for their help. You’re then given the option of choosing a representative from either Udina or Anderson, which represent the Renegade and Paragon choices respectively.
If you let the Council die, then humans will be treated slightly different in the second game while different War Assets will be provided in the third. You’ll also receive Renegade Points for this action. Focus fire on Sovereign and the Council will still die. However, Udina and Anderson will still be around and you receive Paragon Points.
How to Get All Mass Effect 2 Endings
For Mass Effect 2, the ending changes depending on how well prepared you are for the suicide mission. This is based on earning the loyalty of different crew-mates, acquiring different upgrades for the Normandy SR-2, and which roles you assign different teammates during the actual mission.
First off, after getting to know each crew member well enough, you’ll partake in their loyalty missions. Successfully completing these missions will earn their loyalty. Maintaining loyalty also requires having either a high Paragon or Renegade rating once some crew members get into arguments. Just remember to complete all of your loyalty missions before heading to the Derelict Reaper (though Legion’s mission will be available afterwards so you still have time to do that).
As for the Normandy upgrades, pick up the Kinetic Barriers from Tali, the Thanix Cannon from Garrus and Heavy Ship Armor from Jacob. Once the suicide mission begins, head to the Omega 4 Relay immediately. In the actual mission, there will be different segments which require choosing the appropriate person for the job. When infiltrating the Collector Base, choose Tali, Legion or Kasumi as the tech specialist. Go with Garrus or Jacob as the fireteam leader.
The next portion involves moving slowly while remaining in a biotic field. First, you need someone to take the crew back to the Normandy. Go with Mordin above all, followed by Tali, Jack or Kasumi. In the section where the biotic field must be created for protection, select Samara (or Morinth, if you chose her side during Samara’s loyalty mission) or Jack. When making the second squad, go with Jacob, Garrus or Miranda and leave Grunt, Zaeed or Garrus behind. It’s recommended to have Mordin, Kasumi, Tali or Jack with you (since they have better chances of surviving).
Losing a crew member results in the Normal Ending. Doing everything wrong – like not completing loyalty missions, acquiring upgrades etc – will result in most or all of the crew dying along with Shepard. Joker is then left alone – this is the worst possible ending.
Of course, before evacuating the Collector Base, you also have a choice to destroy it or use a Radiation Pulse to disable it. Going with the former (the Paragon choice) will provide the Reaper Heart as a War Asset in Mass Effect 3 along with increasing the chance of the Destroy ending happening. Using the Radiation Pulse will net the Reaper Brain War Asset and increase the chance of Control ending in the sequel.
How to Get All Mass Effect 3 Endings
Finally, we have Mass Effect 3, which has four different endings. The endings include Destroy where the Reapers and all synthetic life are destroyed; Control which sees Shepard controlling the Reapers; Synthesis which has organic and synthetic lifeforms being combined; and Refusal which has Shepard not activating the Crucible.
It’s your Effective Military Strength that determines just how “happy” an ending is though. If your EMS is high enough, then not only does the Earth survive but so do much of the Normandy’s crew. There’s also a hint that Shepard could be alive (when choosing the Destroy ending, that is). The Mass Relays are also in the process of being repaired while battles against the Reapers on Tuchanka, Thessia and Palaven are shown to end positively.
Lower EMS will see the Earth in ruins, different crew members dying, the Mass Relays being destroyed and so on. If you want high EMS, focus on completing all of the side content throughout each game (including scanning each planet in Mass Effect 2).