BioWare really put us through it back in 2012. You remember the red, blue, and green endings, right? People were furious. But if you're looking for a mass effect 3 guide today, you’re probably playing the Legendary Edition and realizing that the math has changed. It's not just about picking a color at the end of a long hallway anymore. It’s about Total Military Strength (TMS) and making sure you didn't accidentally get Tali or Legion killed because you forgot a side quest in the second game.
Look, the Reaper invasion is basically a massive spreadsheet disguised as a space opera. If your numbers aren't high enough, people die. It’s that simple.
The War Assets Math You Actually Need
Forget what you heard about "Galactic Readiness." In the original release, you had to play multiplayer to get your readiness up to 100% or your assets were essentially halved. In the Legendary Edition, that’s gone. Now, everything relies on your TMS. To get the "best" ending—where Shepard potentially survives the Destroy option—you need a TMS score of roughly 7400+ before you hit the point of no return at Cerberus HQ.
Some people say 7800. Others say you can scrape by with 7000 if you made specific choices in Mass Effect 2. Honestly? Aim for 8000. It sounds like a lot, but if you’re scanning planets and finishing the DLCs like Leviathan and Citadel, you’ll hit it easily.
Don't ignore the scanning. It's boring. I get it. You're hovering over a planet, pinging a pulse, and running away from Reaper icons like a game of interstellar tag. But those "Remains of a Turian Platoon" or "Volus Fabricators" add up. A hundred points here and there is the difference between EDI surviving and EDI becoming a pile of scrap metal.
The Quarian and Geth Situation
This is the big one. This is where most players mess up their mass effect 3 guide checklist and end up watching a civilization get wiped out. You want peace? You need "points."
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BioWare uses a hidden point system based on your actions in both the second and third games. You need 5 points to broker peace. You get 2 points if you destroyed the Geth heretics in ME2. You get 2 points if you resolved the Tali/Legion argument with a Paragon/Renegade check. You get 1 point for clearing the Geth fighters on Rannoch.
If you don't have enough points, you’re forced to choose. And if you choose the Geth, Tali... well, she doesn't take it well. It’s arguably the most depressing scene in the franchise. To avoid it, ensure Tali wasn't exiled in ME2 and that you definitely did the "Geth Server" mission in ME3 before the final assault.
Priority Missions Are a Trap
The game labels main story quests as "Priority." This is a lie.
In any decent mass effect 3 guide, the first rule is: Priority missions are the last thing you should do. When a mission is labeled "Priority: Tuchanka" or "Priority: Citadel II," it usually acts as a trigger that expires side quests. If you haven't helped the Grissom Academy students before Tuchanka, they’re gone. You'll eventually face them later as Cerberus phantoms. It’s dark. It’s also a waste of war assets.
- Grissom Academy: Do it immediately after Palaven. Jack is there. If you wait, she’s "re-educated" by Cerberus.
- The Genophage: Before you finalize things on Tuchanka, make sure you've found the Primarch's son.
- The Citadel: Visit the docks and the presidium after every single major mission. NPCs move. Side quests trigger just by walking past people.
Why Reputation Matters More Than Paragon Points
Stop worrying about being a "pure" hero. Mass Effect 3 combined the Paragon and Renegade bars into a single Reputation bar. This was a smart move. It means you can tell a jerk to get lost without ruining your ability to persuade a diplomatic envoy later.
The bar is mostly filled by your total reputation. The ratio of blue to red just determines which flavor of "extreme" dialogue you get. If you want the "Best" outcomes—like convincing the Illusive Man to see reason at the very end—you just need that bar to be nearly full. You don't need to be a saint. You just need to be influential.
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The Leviathan DLC is Mandatory
Seriously. If you’re playing the Legendary Edition, don't skip the underwater stuff. Leviathan provides the actual lore behind the Reapers that the base game glosses over. More importantly, it provides a massive chunk of War Assets. It’s the closest thing to a "cheat code" for hitting that 7400 TMS threshold without having to find every single lost book on the Citadel for some random NPC.
Dealing with the Ending Controversy (2026 Perspective)
It’s been over a decade. We’ve had the "Extended Cut" for a long time now. The endings are still divisive, but they make a lot more sense if you’ve actually read the codex entries.
- Destroy (Red): Shepard's goal from day one. If your TMS is high enough, you live. The downside? You kill EDI and the Geth. It’s a heavy price for survival.
- Control (Blue): You become the new Reaper AI. You lose your humanity, but you save the tech. It’s what the Illusive Man wanted, which makes it feel "wrong" to a lot of players.
- Synthesis (Green): The "space magic" ending. Everyone becomes a hybrid. It’s the hardest to unlock (requires high TMS) but feels the most like a "happily ever after," even if the ethics are murky.
Most players using a mass effect 3 guide are aiming for the "Shepard Lives" moment in the Destroy ending. To see that tiny gasp of breath in the rubble, you need the highest possible TMS. No shortcuts.
Practical Steps for Your Playthrough
Don't overcomplicate it. Follow these steps and you'll get the best possible result.
- Check your ME2 Save: If you didn't do the loyalty missions in the previous game, some characters are doomed. There’s no way around it in ME3. If Mordin isn't loyal, the Tuchanka outcome is significantly worse.
- Talk to your crew: After every mission, walk around the Normandy. Steve Cortez needs to be talked to multiple times or he dies in the final crash. Specialist Traynor has a side quest that is vital for the Grissom Academy arc.
- The Citadel DLC: Save this for right before the attack on Cronos Station (Cerberus HQ). It’s meant to be a final farewell to the characters. If you do it too early, you might miss out on characters who haven't joined the war effort yet.
- Scan the Galaxy: I know I said it before, but I’m saying it again. If you’re at 6000 TMS and you’re about to start the endgame, go back to the map. Every star system has something.
- The Omega DLC: It’s combat-heavy and doesn't affect the ending much, but Aria’s fleet is a solid asset boost. Plus, you get some of the best power-ups in the game (Flare is ridiculous for biotic builds).
The Final Push
Once you start "Priority: Cerberus HQ," the game is on rails. You cannot go back. You cannot scan more planets. You cannot finish that side quest for the Elcor diplomat. Ensure your TMS is where you want it before you click "Yes" on that mission prompt.
If you’ve followed the path—saved the Geth and Quarians, cured the Genophage with Wrex still alive, and completed the DLCs—you’re looking at a TMS well over 8000. At that point, the galaxy is as ready as it will ever be. Pick your color, watch the cutscenes, and know that you actually did the work to save as many people as the game allows.
To secure the "perfect" ending where Shepard survives, focus entirely on the Destroy ending after hitting the 7400 TMS mark. Make sure you've spoken to Anderson and the Illusive Man throughout the final dialogue sequence to unlock the final charm/intimidate options. This ensures you have the agency to choose your fate rather than being forced into a compromise.