The Mass Effect games will always tell the same story, but always in the same way. The player can deeply customize who and what Commander Shepard really is, from the Commander's combat role to whether they are a noble paragon or a brash renegade, among other things. And the player's decisions will also impact future story beats in huge ways.
The player can decide whom Commander Shepard falls in love with, for one thing, and even customize the Commander's armor and make tough decisions during historic moments in this space saga. The battle of the Citadel in 2183 is a fine example, and the great war against the Reapers is a time for many difficult decisions, sacrifices, and split-second judgment calls. What are some of the hardest choices Shepard will have to make?
10 Whether To Save Or Destroy Maelon's Research Data
During the events of Mass Effect 2, Commander Shepard will learn much more about the controversial genophage from Dr. Mordin Solus, who helped create a modified version of it. During Mordin's loyalty mission on Tuchanka, Mordin and Shepard will encounter Maelon, who is trying to cure the genophage by himself.
Maelon is stopped no matter what, but the real question is whether Mordin should wipe Maelon's data and prevent it from being misused, or save it just in case Mordin really does have a change of heart. Before playing Mass Effect 3, it's tough to say whether a genophage cure is what the galaxy needs.
9 Whether To Spare Or Kill The Rachni Queen On Noveria
Commander Shepard visits the icy world of Noveria to pursue Matriarch Benezia, and the Matriarch is defeated in a boss battle in the mysterious Peak 15 lab. But there is another major party here: the last surviving Rachni queen, whose hatchlings were being misused as beasts of war by researchers.
The Rachni queen promises that her race is gentle and that the Rachni Wars had been a tragic mistake for both sides. But will Shepard risk it and spare her life, allowing the queen to restart her race elsewhere? Or is it safer to destroy her, and guarantee that no more Rachni Wars will happen?
8 Whether To Kill Balak Or Save The Hostages
In the Bring Down the Sky DLC, a Batarian terrorist team is about to plow an astroid right into the Terra Nova colony, and Shepard soon confronts the criminal mastermind Balak. However, Balak has already taken everyone in the asteroid base hostage, and he even set some bombs. Shepard doesn't have time to capture Balak and spare the hostages.
On one hand, what kind of hero is Shepard if the bombs go off and everyone is killed? This will surely haunt Shepard for years to come. Then again, letting Balak go to save those hostages means Balak is free to commit more crimes like this elsewhere, and Shepard might not be around to save the day again. What to do?
7 Whether To Risk The Alliance 5th Fleet To Save The Destiny Ascension
During the final battle for the Citadel, the Citadel fleet is struggling against Sovereign and the Geth fleet, but the Alliance is ready to send aid. Once Shepard defeats Saren, there is an opportunity to open the Citadel's closed arm and let the Alliance 5th fleet intervene in the battle.
Doing so is highly risky, however, and the Alliance may lose many ships that it cannot easily replace while fighting Sovereign. That, and the Council has been a real thorn in Shepard's side. Renegade Shepard may let the Council die, though doing so tarnishes humanity's image later on.
6 Whether Or Not To Destroy The Collector Base
In hindsight, this is an easy decision to make, in light of the events of Mass Effect 3. However, at the time, Shepard may be torn on what to do with the Collector base. Shepard always defeats the Collectors here, but then Shepard is given the option to set off an energy pulse to kill all remaining Collectors while sparing the base itself.
It's true that this base has unique and incredible technology that the Alliance could use against the Reaper fleets, and an opportunity like this will never present itself again. But on the other hand, the Illusive Man is manipulative and shady, and he is liable to misuse Collector tech if given the chance. Is this risk worth it for humanity's defense?
5 Whether To Capture Or Kill Oleg Petrovsky
This trilogy has several exciting DLC packs to offer, from the amusing Citadel DLC to the nerve-wracking Bring Down the Sky, and then there's Omega. In this DLC, a Cerberus officer named Oleg Petrovsky one-upped Aria T'Loak on her home turf and assumed command of the lawless Omega.
Shepard will help Aria reclaim her home, but the loose end is, of course, Oleg himself. Aria simply wants to kill him out of anger and to send a clear message to Cerberus, but Paragon Shepard will spare him as a prisoner of war who carries vital intel. But that's risky. Cerberus is slippery and deceptive; what if Oleg escapes again, on the way to an Alliance facility?
4 Whether To Use Video Evidence To Clear Tali's Name
During Tali'Zorah's loyalty mission, Shepard learns that some Geth took over the Alarei, a lab ship in the Quarian Migrant Fleet, and Shepard and Tali will secure that ship while also hunting for evidence of Tali's innocence. The evidence is certainly there, but it comes with serious strings attached.
Video recordings make it clear that Tali's beloved father, Rael'Zorah, was responsible for the Geth attack on the fleet, and Tali would much rather not use this evidence to clear her name. If Shepard lacks sufficient paragon or renegade, though, the Commander must choose between honoring Tali's wish and proving her innocence. Settling Tali's court case will take some smooth-talking, that's for sure.
3 Whether To Save The Quarians Or Geth On Rannoch
If Commander Shepard has a lot of paragon or renegade points, then it's possible to have it both ways during this campaign, but that won't always be the case. In the Tikkun system, the Geth and Quarians are waging war, and even with Legion's help, it's not clear how this war will end. Then Legion starts to upload AI codes to all Geth.
Time is running out, and if Shepard can't save both sides, then the Commander must either save the Quarians by assassinating Legion or save the Geth by protecting Legion instead. Whichever side Shepard favors will exterminate the other in one final space battle.
2 Whether To Sabotage The Genophage Cure To Secure Salarian Aid
For paragon Shepard, this choice is rather easy, since personal loyalty to Urdnot Wrex comes before any backroom deals with the Salarians. For renegade Shepard, though, Dalatrass Linron's offer is far more tempting, and renegade Shepard might not be 100% sure that the brutish Krogan even deserve the genophage.
Curing the genophage will alienate the Salarians, while sabotaging the cure will fool the Krogan into cooperating while encouraging Dalatrass Linron to provide high-tech Salarian fleets and scientists for the Crucible project. Shepard can't easily turn their nose up at such substantial aid, but is it worth betraying Wrex?
1 Whether To Save Ashely Or Kaidan On Virmire
This is the classic dilemma of the Mass Effect games, and Shepard must be ready to consign one of their trusted squadmates to death. On the world of Virmire, Saren Arterius is studying indoctrination and cloning Krogans, and a Salarian team is ready to help blow the place up with an improvised bomb. But there are a lot of Geth defending the location.
Shepard's team splits up, and not everyone will make it back to the Normandy. Between Kaiden Alenko and Ashley Williams, one of them will oversee the bomb while the other is holding off the Geth, and there is only enough time to save one of them. Who will survive?