Legion: A House Divided

Legion has learned that the geth heretics have adapted a Reaper virus which, when uploaded, will compel the normal geth to join them in their war against organic life. This virus must be stopped.

Acquisition
The player will recover Legion at the end of the Reaper IFF mission and may choose to keep it onboard and activate it. Sometime after activating Legion, Kelly will say that Legion wants to talk. If the player has already completed every other mission and assignment, this mission will be available immediately after talking to Legion for the first time (otherwise the player would not be able to leave the Normandy to install the IFF). The geth have written a virus that would bring all geth to their side. The virus is at Heretic Station.

Preparation
Legion can use an assault or sniper rifle, and has the valuable AI Hacking and Combat Drone powers: putting some points into AI Hacking is particularly recommended for this mission. Since the geth you will be facing emphasize shields for defense, someone with Overload and/or Disruptor Ammo would be a useful companion. Also, the Heretic Station is a low gravity environment, since the geth don't require gravity to maintain maximum effectiveness, so physics based attacks such as biotics or Concussive Shot have increased effect: Enemies will often be sent flying, giving you more time to shoot them. If you're a Vanguard you will particularly enjoy the increased force your Charge has on this mission!

Heretic Station Approach
Shepard and the team approach Heretic Station undetected because of the Normandy's stealth systems. Joker remarks that should any geth look out a window they are not cloaked to the visible spectrum; however, Legion replies that windows are a structural weakness that are not present on the station. The squad boards the station.

Heretic Station Entrance
When you arrive Legion tells Shepard that there is no air and little gravity because the geth require neither. Legion then informs Shepard that there is an alternative option to the plan. Instead of destroying the station, Legion says that the virus is finished and Legion could modify the virus and bring the geth back into the main geth fold, which would stop them from aiding the Reapers. Legion is unsure about either path and when asked says it needs more data before drawing a conclusion. Move down the hall, grab the Medi-gel and head into the next room.

Upon entering the room, Legion will say that the geth are currently in separate nodes to clear out the excess data that Legion uploaded at the start of the mission. The green lines on the floor of the rooms should not be crossed unless you are in position to take out the geth attached to the hubs. It’s worth noting that the NPCs in your team can also cross the lines and trip the alarms as well. Move around the room and get into position before stepping on the line. Overloading or destroying the hubs sends the geth attached to it into shock for a few seconds and allows you to make the first strike. The Geth Troopers and Geth Hunter that were attached to the node eject and attack you. It is easy to take them down before they have a real chance to hurt you. When they are down a cutscene will play and Legion will explain how the hubs work and explain the shared geth experience. You can again ask about the decision but again Legion is unsure. Salvage the hub for credits, and do so for the rest of the mission.

The next hallway contains some inactive Rocket Drones. Legion says that it can hack them and they will fight for about 10 seconds before they self-destruct. As you move down the hallway the door at the other end will open and some geth will spill out. Hack the Drones, take cover and fight them until they fall. Move on and into the next room.

You can take friendly fire from the rocket turrets, so don't stand in front of them! You can also be damaged when they self-destruct or are destroyed by enemy fire.

Be careful as you enter this room because there are two geth hubs. One ahead to the left in the alcove; the second is in an alcove next to the exit door. You will have to cross the lines to get into cover for this room but focus on the geth ahead of you for now. Quickly cross the line and overload the hub if you can (shoot it if you can't), thus activating the geth. Concentrate fire on the dangerous Geth Hunter to make sure it goes down immediately. Once those geth are down, make sure to take out the other Geth Hunter first so it does not close in, then move to where the other hub is and take out the other geth. You can also use the window of sorts on the entrance hallway for another good position for the second group. When the geth finally fall, salvage the hubs and move into the hallway.

This hallway has some Geth Troopers so use cover and take them out. When the geth fall move to the end of the hallway and grab the Medi-gel. Move up the ramps to the next room. It is recommended you save before entering this room. This room contains a storage room of sorts and has little cover. Find what you can, usually along the railings on the side you enter from. There are two Rocket Drones in the center of the room and activate only one at a time. There will be two waves of Geth Troopers and Geth Hunters. Usually the geth would run through the center of the room, but watch out for Hunters and Troopers that will not go through the center and will go across the sides. Once you manage to take down the geth, move around the room and collect clips, you are probably low on ammo now, so take the time.

Move to the door, open it, and go in the hallway. At the other end are some power cells and Medi-gel, grab them both before moving down the ramps to the next area and deeper into the station. Once you are down the ramps go to the right and pick up the refined palladium and the head over to the door. Save the game before going in.

Heretic Station Interior
Once in the next room immediately take cover and combat the geth that are already in the room. There is a collection of two Geth Troopers and a Geth Hunter that will cloak once you enter the room. Target the Geth Hunter first and then the Troopers. There is an inactive Rocket Drone in the room that can assist you in this fight. Once the geth are down the non-Legion squadmate will ask how long the room outside the windows is. Legion will say that since the station is 15km long the room likely runs the length of the station. Before leaving the room go behind where you entered to hack a terminal for a Geth Shield Boost upgrade. Move through the next door and watch out for the data lines on the floor as you move up through this room with the four massive tanks.

Once you emerge in the next room, take cover as there are two more geth hubs in the room, one to your left, and the other to the right. If you can, take out one of the hubs at a time. Pick one of the hubs to which you can get a clear line of sight and either Overload it or shoot it. Try to take out this first group of geth quickly (or at least the Geth Hunter), before the other group of geth emerges from its hub. Now use cover, powers, and whatever else you can do to get the geth to fall the fastest. Note that you can flee back up the stairs if things get too hot, and if your squadmates fall then reviving them when they are behind the geth will distract them and help you get back into the fight. Opening with a thorough Arc Projector-ing of one of the geth hub rooms will let you put a lot of damage on the first group of geth and still have time to get to cover before the second group emerges.

Once they are down, pick up clips and move on. The next hallway contains what appears to be a massive server room. When you pass one of the windows, you can initiate a conversation with Legion. It will explain that the room is a server room, of sorts: the massive computers contain the sum of the collective memories of these geth. Legion takes a good look and reflects on how the heretic geth and the true geth have grown apart. You can comment on that and ask him about the decision. It will still be unsure and a debate will be raging in the core.

Move into the next room and for once, there are no enemies. Take a moment to observe your surroundings and don't activate any of the Rocket Drones yet; you will regret it in a few minutes. Note the location of the only two ammo cartridges in the room - these respawn, and you will likely need to return to them from time to time during the ensuing battle.

Move to the console in the middle, save your game, select the console, and the dialogue will come up with some options. Legion says that the virus is completed and that it must be deleted. Legion will say that while the virus is being deleted/altered, all the geth on the station will become aware of the squad's presence and will try to stop them. Prepare for wave after wave of geth. So dig in and wait for the first wave.

Hold Position
This next area is just about killing geth before they have a chance to get to your position. There are a few strategies for winning this protracted battle. Four waves on Insanity - the number may vary on lower difficulty levels.
 * Wave 1: Geth Troopers
 * Wave 2: Geth Troopers, Geth Rocket Troopers
 * Wave 3: Geth Troopers, Geth Hunters
 * Wave 4: Geth Troopers, Geth Rocket Troopers, Geth Hunters

Strategies for fighting the onslaught:
 * Don’t activate all the Rocket Drones in one wave. There will be as many as four waves and each wave will be progressively harder. If you manage to save everything until at least the Hunters start to appear, you will be much safer.
 * There are six Drones on the lower level and two on the upper level, save the upper ones for the last wave, and not until you need them.
 * Order your teammates to one of the two flanking staircases while you personally cover the other.
 * Have one squadmate cover each side and take cover in the center providing cover as necessary.
 * If the attacking geth start climbing the stairs, you can take cover behind the three boxes forming an arc behind the geth terminal. The geth forces will take cover closer to the top of the staircase, and you can have your squadmates use their powers on one side, while you handle the other. Oddly enough, the Geth Hunters won't try to storm your position.
 * Try to use AI Hacking on the Rocket Troopers as this will both distract the geth forces and help prevent the Rocket Troopers from flushing you out of your cover.

Basically, don’t allow the geth to the upper platforms. If they do and only on the last wave use the two Rocket Drones because they can provide a last defense against Geth Hunters. Once all the geth are down you re-engage conversation with Legion. It states that the virus has been deleted and asks what the next step is. You can, for the last time, ask for Legion’s opinion and again it cannot decide. You can also ask why it is leaving the decision to you. It replies that you have fought the heretic geth and that is why the decision is left to Shepard. Make your choice.
 * If you choose to rewrite the geth, Legion will state that the station will release an EMP to rewrite them and it will also damage any unshielded organic tissue in a large radius. The station is unshielded. Your other squadmate states that that would have been nice to know earlier.
 * This solution might present a problem down the road with the integration of the memories of the heretic geth into the geth collective, and will make the geth stronger as a whole, but will give you paragon points.
 * If you choose to destroy the station then Legion states that it will collapse the antimatter confinement bottle in the station's core, destroying the station and anything left onboard.
 * This problem will be a more immediate solution. This station, however, is only the main station, and there will still be holdouts, which will present problems in the future. This option will also give you renegade points.

No matter what you choose, now you have three minutes to evacuate.

Evacuation
Once the conversation ends, the three-minute countdown will start. At the end of those three minutes, you will die if you can’t get out. This is actually plenty of time to destroy all the remaining enemies as long as you don't mess around, so move deliberately but don't panic as that can lead to fatal mistakes. Go down the hallway to the right of the console and take cover as the geth will try to stop you. Keep moving and shooting until you reach the second turn. Send your squad in first because there is a Geth Prime around the corner. Sending your squadmates in first will distract it while you can use the corner as cover to take out the Geth Prime. Watch your remaining time, because if you take too long you will die.

You do not have to defeat all the enemies to complete the mission - tapping the airlock at the other end of the room will result in instant victory and a cutscene. An Infiltrator, for instance, can cloak and need not hang around to take down the Geth Prime, and other classes may also be able to "leave early" once the geth are distracted (e.g. with AI Hacking, Stasis, or even Charge).

When you can, move across the room they were in and to the door to exit back to the Normandy. The ending cutscene will play, showing your decision of whether to rewrite the heretics or blow up the station. If you chose to rewrite, an EMP blast will show; if you chose to destroy the base, it will blow up.

Normandy
Once back on the Normandy Joker will inform you that Tali and Legion are having a heated discussion, if Tali's loyalty mission has already been completed. Once you arrive at the AI Core, you see Tali aiming an SMG at Legion. She yells at you that, even though she was willing to work with a geth, Legion was trying to send classified information about the Migrant Fleet to the geth. Legion states in its defense that it knows the quarians were performing weapons tests on geth and that it was trying to protect its people from a possible attack, further citing Tali's willingness to be exiled for the sake of her own people as a similar action. If Tali was exiled, Legion will, instead of citing Tali's willingness to be exiled, question why Tali still protects the quarians.

You can either side with Legion or Tali or you can also use a Paragon or Renegade option to get them both to agree. If you use this option then Legion will agree not to transmit Tali's data for the sake of "unit cohesion," and Tali will volunteer some non-classified data for Legion instead. If you fail either option then you will lose the loyalty of one of the squadmates.

It is possible to salvage the loyalty of Legion if you had insufficient Paragon/Renegade to break up the initial confrontation with Tali. During the initial confrontation, tell Legion to stop its transmission, thus maintaining Tali's loyalty but losing Legion's. Then, after the conversation ends, immediately speak to Legion again. A high Renegade score will allow you to tell Legion that you "lied" about the data transmission to keep Tali happy. Legion will recognize this as "a logical decision", regaining Legion's loyalty. The required Renegade is high, but not as high as the initial conversation. If you choose this option, then both Legion and Tali will remain loyal.

Enemies

 * Combat Drone
 * Geth Trooper
 * Geth Prime
 * Geth Hunter
 * Geth Rocket Trooper

Mass Effect 3 Consequences
In Mass Effect 3, if you choose to ally with geth forces or make peace between them and quarians, if you chose to rewrite the heretics, the Geth Fleet war asset will receive a significant bonus (+150, 450 total). However, destruction of the heretics provides similar penalty (-150, only 150 total).

Bonuses and penalties to Quarian war assets are exactly the same, just in the opposite direction (3 x +50 if destroyed or 3 x -50 if rewritten). This means, if you choose to make peace and acquire both geth and quarian help, your maximum War Asset value will be the same any way you decide here.

During Priority: Rannoch, when the time comes to choose between siding with the geth, siding with the quarians or resolving the conflict peacefully, the fate of the heretics is one of the numerous factors in whether peace will be a possibility or not. Destroying the heretics works in favour of peace, but isn't required.

Mission Summary
Renegade Route: Destruction of geth heretics may change entire galactic landscape. Bolstering observation of geth space to monitor any fleet movements. Regardless, data recovered from geth station offered valuable insight into AI social and technological processes. Legion should be committed to the mission after Shepard's help with the geth heretics.

Paragon Route: Rewriting of geth heretics will make main geth faction significantly more powerful. Given perception of Reapers, they may be possible allies, though long-term cooperation remains unlikely. Regardless, data recovered from geth station offered valuable insight into AI social and technological processes. Legion should be committed to the mission after Shepard's help with the geth heretics.


 * Experience Reward: 750 (937)
 * Credits: 30,000
 * Cerberus Funding: 15,000
 * Credits Found: 15,000
 * Resources:
 * Palladium: 2,000
 * Upgrades:
 * Geth Shield Strength (Cyclonic Particles)
 * Powers:
 * Legion: Geth Shield Boost

Trivia

 * When Shepard asks about how the virus works, in the first conversation, Legion will respond with; "An equation with a result of 1.33382 returns as 1.33381. This changes the result of all higher processes. We will reach different conclusions." This is a reference to the Pentium FDIV bug.
 * During Legion's attempt to find consensus, Legion states that it has 573 processes voting for re-purposing the virus and 571 voting for destroying the station, leading to a total of 1,144. This is 39 fewer than the stated total of 1,183; since Legion mentions earlier that its high-level processes had not reached consensus, one possibility is that some of its lower-level processes do not participate in this decision. Alternatively, it may be that those 39 processes are still "on the fence", or perhaps even abstaining - that is, if the geth have such a concept.
 * When hacking turrets aboard the station, Legion occasionally utters "Executing sudo command." This is likely a reference to the common Unix command sudo, which allows ordinary users to run the commands that require superuser (root) permissions.
 * When hacking turrets, Legion will also sometimes say, "Assuming control," similar to Harbinger's statement when possessing Collectors.
 * Since this mission is called "A House Divided", this might be a reference to one of US President Abraham Lincoln's first speeches on slavery, or a reference to Matthew 12:25b in the Bible, when Jesus said, "Every kingdom divided against itself will be ruined, and every city or household divided against itself will not stand."