The Mass Effect 3 endings are still a sore point for some players, who felt that they didn't accurately represent the years of decisions made during the trilogy, or indeed appropriately sum up their time spend adventuring with Commander Shepard. BioWare tried to address this by releasing The Extended Cut update, which is the version included with the Mass Effect Legendary Edition and makes an additional outcome available, however this still doesn't resolve the issue that everything you've done before you're pretty much left with a single choice to finish this story. When it comes down to it, determining the best Mass Effect 3 ending is a matter for personal opinion, but we've outlined all possibilities so you can make an informed decision.
The Total Military Strength you've managed to gather during the course of the campaign will directly affect the Mass Effect 3 endings you have available, as with a TMS of less than 1750 you will only have one possible outcome – either the Destruction ending if Shepard destroyed the Reaper Base at the end of Mass Effect 2, or the Control ending ending if Shepard saved the Reaper Base. At a TMS of 1750 or above you can choose between those two options, and at 2800 or more the third Synthesis ending is also available. You can check what your current TMS value is by accessing the War Terminal within the War Room on the Normandy, so before you start Act 3 and pass the point of no return you should ensure that you've reached the level you require for your preferred choice from the Mass Effect 3 endings.
How to increase Mass Effect 3 Total Military Strength and change ending options
Your Mass Effect 3 Total Military Strength is calculated through a combination of the crew, weapons, ships, armies, items, and technology you amass throughout the campaign, known collectively as War Assets. Some of your TMS comes from previous missions you completed and squad members who survived the events of Mass Effect 1 and 2, so it pays to play through those two games first and carry over your save – if you jump straight into Mass Effect 3, you'll be at a disadvantage and will have to work harder to build up the necessary TMS for your preferred Mass Effect 3 ending.
In the original Mass Effect 3, your Total Military Strength was determined by multiplying your Effective Military Strength (the sum of your War Assets) by your Galactic Readiness, a scale from 50-100% which you could increase by playing multiplayer matches and using companion apps. As there is no longer a multiplayer mode or any apps connected with the Legendary Edition, the Galactic Readiness element has been completely removed from the equation and your Total Military Strength is now just your Effective Military Strength. To maximise your Total Military Strength and open up the best Mass Effect 3 endings, you should carry over a save from previous games, complete as many side missions as possible, and use Mass Effect 3 planet scanning through the Galaxy Map to collect additional War Assets to bolster your forces.
Mass Effect 3 ending - Destruction (Red)
For this first Mass Effect 3 ending, head along the right hand path in the Crucible towards the red light then repeatedly shoot the panel on the machinery, to send out a destructive blast across the galaxy that wipes out all synthetic life including the Reapers. At a lower level of Total Military Strength this will also destroy everything else, though if you're prepared enough then it's possible to save Earth, the Normandy crew, and Shepard. This is the only ending choice where Shepard can survive.
* this choice at <1750 TMS is only available if Shepard destroyed the Reaper Base at the end of Mass Effect 2
Mass Effect 3 ending - Control (Blue)
This second Mass Effect 3 ending is available by following the left hand path in the Crucible, towards the blue light and then grabbing the two beams. This will cause Shepard to sacrifice themselves to merge with the Reapers, taking command of their forces and leading them away. It is not possible to save Shepard in this scenario, and the only difference with increased TMS is that Earth is spared from taking any significant damage.
* this choice at <1750 TMS is only available if Shepard saved the Reaper Base at the end of Mass Effect 2
Mass Effect 3 ending - Synthesis (Green)
Should your Total Military Strength be at 2800 or higher then this third Mass Effect 3 ending is also possible, by making your way along the central path in the Crucible towards the main beam of energy. Shepard will take a run up and dive into the beam, sacrificing themselves to merge all organic and synthetic life in the galaxy. This renders the Reapers obsolete and prevents further attack, though again there isn't any way to keep Shepard alive and only one outcome can be achieved where everyone else is saved by being synthesized.
|≥2800||Saved||Squad survives and are synthesized||Dies|
Mass Effect 3 ending - Refusal
This fourth Mass Effect 3 ending is the one that was added in later to the game, allowing you to refuse all three of the previous outcomes by telling the Child "I reject these choices!" Shortly after, the Child says "The cycle continues" and Reapers can be seen wreaking destruction outside the Crucible before the main beam goes out. A message of hope from Liara is later shown being broadcast to an underground bunker, recounting the war with the Reapers, and the Stargazer states that this knowledge was used to protect future civilizations.