Mass Effect Legendary Edition

Wanted to make a straightforward and comprehensive guide for this achievement because it can be annoying if you dont know exactly whats up with this one.

There are checkpoints the game checks for after you go through the Omega-4 Relay, the Tartarus Debris Field, the Collector Base, and the Hold the Line sections.

i modeled this solution off of the Mass Effect Wiki and ign website with my own personal injections.



Tartarus Debris Field

Silas Armor Check

This happens when the Oculus lasers attack your ship and checks if you have upgraded this at the Normandy upgrade center.

If you did upgrade this, then Jack will live.
If you did not upgrade this, then Jack will not live.

Cyclonic Shield Check

The next check is whether you upgraded the Normandy's shields.

If you did upgrade this at the station, nobody will die.
If you didnt, a squad member will die, in this order:

Kasumi > Legion > Tali > Thane > Garrus > Zaeed > Grunt

The order will change based on who you have recruited and have taken with you into the shuttle bay. (If you didnt upgrade the shields and want a specific member to survive, put them in your squad to make sure they surive this part).



Thanix Cannon Check

The third and last checkpoint for this section is for the heavy cannon upgrade.

If you did upgrade this option, everyone survives this part.
If you didnt upgrade, someone will die in this priority order:

Thane > Garrus > Zaeed > Grunt > Jack > Samara / Morinth.

Since this takes place right after the cargo bay fight, theres no way to protect any unloyal squad members with this one.


Collector Base


Vent Specialist

The first option inside the base you are faced with is picking a vent specialist to go alone, and also a second fireteam leader. You'll NEED to pick a loyal squad member for them to live. if you dont, they will die at the end. It is only the person who you pick as the Vent Specialist who will be at risk of dying here.


For the Vent Specialist, you should pick a Loyal Tali, Loyal Legion or Loyal Kasumi.
For the Fireteam Leader, you should pick a Loyal Miranda, Loyal Jacob or Loyal Garrus.

If you fail to pass even one of the above checks, the Vent Specialist will die.

you need to pick a tech expert as the Vent Specialist since only they can pull off the vent task. Additionally, the Fireteam Leader needs to be someone with experience leading a team. However, even if you meet the above requirements, if either the Vent Specialist or the Fireteam Leader are NOT Loyal, the Vent Specialist will die.

(i personally chose a loyal Tali for the vent and Jacob for the second team leader).

Normandy Crew



After this section you meet the Normandy Crew, the one part i found particuarly frustrating in the design of the game. According to Game Informer, how many missions you did before lauching this one determines whos left alive.


If you did zero Missions / Assignments and went through the Omega-4 Relay as soon as possible, all of the crew will survive.
If you did 1-3 Missions / Assignments after the crew were kidnapped, half of the crew will die, including Kelly, Gabby, Ken, and Mess Sergant Gardner .
If you did 4 or more Missions / Assignments after the crew were kidnapped, all of them except Dr. Chakwas will die.

I personally wasnt able to find a way in my playthrough to have all loyal squad members and immediately go into the suicide mission to save the entire crew, so perhaps do Tali's loyalty mission as soon as it becomes available as i put hers off till the end.


Long Biotic Walk and Second Fireteam

At this point you will split into two teams, and you will need to choose a Biotic Specialist and a leader for the second fireteam.

For the biotic specialist

If you pick a Loyal Jack, Samara or Morinth, your team will survive.
If your pick is anyone else, and/or Disloyal, then a member of your accompanying squad will die, in the following order of priority:
Thane > Jack > Garrus > Legion > Grunt > Samara > Jacob > Mordin > Tali > Kasumi > Zaeed > Morinth.

(for some reason i found out Miranda isnt capable of doing this part, even though she claims she can so i wouldnt pick her).

Second Fireteam Leader

This works similar to the Vent Specialist section.

If you pick a Loyal Miranda, Loyal Jacob or Loyal Garrus, they will survive.
If you pick anyone else, or somebody not Loyal, they will die.

However this time, it would be person directly who you pick who is in risk of dying if they arent Loyal.

Crew Escort

If you choose somebody Loyal to escort the crew, both the escort and the crew will survive.
If you choose somebody Disloyal to escort the crew, the escort will die but the crew survives.
If you DON'T decide to give the crew an escort, the crew will die.

If strong characters like Grunt, Garrus or Zaeed have died before this point, you'll want to avoid sending another strong character as the Escort here as that may negatively affect the outcome of the Hold the Line section.

(i personally chose a loyal Kasumi for this).
(Note: The Crew Escort section here is NOT necessarily for this particular achievement. If the crew happens to die, you can still get the achievement. i just personally like to save as many people as I can).

Finale

The last actual decision you need to make is who will accompany you and who will hold the line in the endgame here. This first decision is easy.

If a Squad Mate you take with you is Loyal, they will live.
If a Squad Mate you take with you is NOT Loyal, they will die.

Holding the line


This part was easily the most annoying to try and figure out. This section is calculated differently from all the other sections for some reason.


Essentially, whether a squad member lives or dies is determined by an average Point value determined on who makes up the group, and whether or not they are loyal. Here are the base point values of your Squad Mates:

4 Points: Grunt, Zaeed, Garrus
2 Points: Thane, Legion, Jacob, Miranda, Samara / Morinth
1 Point: Jack, Kasumi, Tali, Mordin
If any squad member is not Loyal, their point value is reduced by 1.

The average number of Points the team has will determine how many of them die. If the average is above 2, everyone on the team will live. Anything below that will risk up to three party members dying.

While the exact requirements will vary, in general an average of 1.5 will result in one death, an average of 1 will get two deaths, and an average of 0.5 - 0 will get three deaths. This means that if four or more characters are left to Hold the Line, it's impossible to have all of them die.

The pecking order of deaths is:

Mordin > Tali > Kasumi > Jack > Miranda > Jacob > Garrus > Samara / Morinth > Legion > Thane > Zaeed > Grunt

Because deaths caculated on the team's average Point value, a smaller team can still survive if strong characters are present. For example, Grunt can survive entirely on his own because even his Disloyal point value is 3. Having a Disloyal Tali with Grunt will still result in both of them living, because the team's Point average will be 2.

Basically the more loyal squad members you have, the better youll be in this section.

If Shepard Lives

The final check in the Suicide Mission is at Shepard's jump towards the Normandy.

If 2 or more squad mates have survived, Shepard successfully makes the jump and will live.
If 1 or 0 squad mates have survived, Shepard doesn't make the jump and will die.



Best of luck to you and upvote if this is straightforward and helpful :)

i'll include a short video guide, but pretty much right before the 'acquire reaper iff' mission, make sure just about everyone is loyal (no more than two disloyal, better if no one is), but instead of giving a very open vague guide, i'll just tell you what to do so you dont get confused or mess up cuz a lot of guidies online are just awful.

Make sure to have all Normandy upgrades, use ONLY loyal people (if not loyal they'll die), and select the following people when asked for:

Tech Specialist: Tali or Legion
Fireteam Leader: Garrus or Miranda
Biotic Specialist: Jack or Samara/Morinth
Diversion Leader: Garrus
Crew Escort: ANY Loyal Person

After this it'll ask you to pick two people to the boss fight while the rest hold the line, instead of trying to explain the number value system, just take Kasumi and Tali. (Mordin and Jack also work too)

Some excellent guides on here already. I just wanted to let you know that if this doesnt pop, after the credits select to continue the game.

You can reload previous saves from here but if you forgot or made a wrong save there is an option to RESTART this mission

There's a full guide for the 360 version of this achievement. I will copy the info down below and link the original. All credit for this guide is with @Major Alenko

Since the Prima guide was utterly useless for figuring out the endgame and there seems to be a great deal of confusion on the boards about how this works, I thought I'd spend some time running different teams through the endgame to see what variables are at work.

Space Battle.
If the Normandy is not properly upgraded, each missing upgrade will result in a team member death before you even start the assault on the Collector base. If you take this team member with you during the oculus fight, or haven't recruited them, or they are dead, a different character dies instead.

-No Silaris Armor: Oculus beams punch through; Jack dies.
-No Cyclonic Barrier Shielding: Engine core overloads; Tali (or Legion or Thane) dies.
-No Thanix Cannon: Normandy charges in with main guns; Thane (or Garrus) dies.

Base Assault.
For the assault itself, there appear to be three types of characters that are required for the various key roles:

-If the Tech Specialist is not one of those listed below, they will die at the first rendevous.
-If the first Fireteam Leader is not a leadership character, the Tech Specialist will die at the first rendevous.
-If the second Fireteam Leader is not a leadership character, they will die at the second rendevous.
-If the Biotic Specialist is not powerful enough, one of your current squad members will be swarmed by seekers and die.
-If the crew survivors are not escorted, they will die (any character can do this and the crew will live).
-If the Heat Exchanger valves are not opened in time, the Tech Specialist will die and you're forced to restart.
-If there aren't enough Combat Specialists left behind to hold the line while you fight the last boss, characters die
-Some characters are worth more as Combat Specialists than others; these point values are still being tested
-Characters with low point values are the first to die if there aren't sufficient points to hold the line

The following characters are the only ones that will succeed at their respective roles:

Tech Specialist
* Tali
* Legion
* Kasumi

Leadership
* Miranda
* Jacob
* Garrus

Biotic Specialist
* Samara / Morinth
* Jack

Crew Escort
* Any loyal character

Combat Specialist
* Zaeed
* Grunt
* Garrus
* possibly other partial contributors

Disloyalty (Normal Loyalty).

Not having a character's loyalty has different effects depending on what you do with them:

-Having disloyal characters in the above key roles will result in deaths, regardless of whether they are suitable or not.
-A disloyal crew escort will sacrifice their lives to protect the crew (the crew will still make it).
-Disloyal characters don't get as many 'points' as loyal characters when holding the line and are more likely to die
-Keeping disloyal characters in your active squad prevents them from dying, except for...
-In the final boss fight, disloyal characters in your active squad will be crushed by rubble after the fight and die.
-If all team members are dead, Shepard misses the final jump and lets himself fall to his death rather than risk Joker's life.
-Note that with all 11 team members recruited, it's actually not possible to kill off all of them and get yourself killed.


Kidnapped Normandy Crew. ( Not essential for the achievement)
If you do not go through the Omega-4 relay quickly enough after the Collectors kidnap the Normandy crew, the captured crew members will die off in the endgame. Watching Kelly get liquefied was particularly horrifying. Who dies depends on how many missions you did after the Joker level (actual clock time does not affect the outcome, nor do relay jumps, fuel spent, or landing on Illium/Omega/Citadel/Tuchanka; any quest, big or small will count though):

-If you use the relay immediately, everybody survives; Horizon colonist gets liquified instead.
-If you do one mission, Kelly, engineer Daniels, mess sergeant Gardner, and half the crew dies.
-If you do two missions or more, everyone except Dr. Chakwas dies.

Legions loyalty mission.
Note that if you activate Legion and learn about his loyalty quest immediately after the Reaper IFF mission, the Collector attack / Joker level will wait for one extra mission before triggering. This allows you to complete all the loyalty quests before the crew is even kidnapped (assuming you did the other ones already).

The X-Factor.

Some people also report having trouble keeping a character (typically Mordin) alive at the end, where they must hold the line until Shepard kills the last boss. This seems to be related to a choice or choices made during the final mission, as rearranging team roles from the same savegame will affect whether this mysterious death happens or not.



I will add that, while Mordin is useless in most areas of the game, he is a champion at being able to escort the survivors back to your ship.