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Catwalks in the headquarters

The Illusive Man's headquarters have been located, and the Alliance is prepared to attack to recover the Prothean VI that holds the key to the Catalyst. Once the attack is launched, the Alliance will be fully committed to the final fight against the Reapers. Assault the base when ready.


Prerequisite: Priority: Horizon

This mission is acquired immediately after the events at Sanctuary.


When you attempt to dock at the Illusive Man's base, revealed to be a space station orbiting Anadius in the Horse Head Nebula, Hackett will talk with you over vidcomm, mentioning that the final assault on Cerberus will expose the Crucible to Reaper eyes and must be considered the first phase of the assault on the Reapers themselves. He will give you the chance to back out, which you should take seriously: this is the game warning you that you are about to hit the point of no return. The dialogue options to start or postpone the mission do not affect Renegade or Paragon scores.

Warning: Once you start the mission, the remainder of the game runs in (virtually) locked progression. You will not be able to complete side missions, DLC missions, or visit the Citadel. You can, however, use the Normandy procurement interface. Furthermore, if you complete the game and then re-open your save, this is where you'll find yourself. If you've got a romance going with someone on the Normandy, that character will come and visit you in your bunk. There's even another ghosts-and-forests nightmare. It's the beginning of the end.

In other words: got anything else you want to do first? Do it before hitting Cronos Station.


EDI and Joker before the mission

EDI is a required squadmate for this mission. Her kit is similar to an Engineer's, giving her lots of tech options but limited direct firepower. As such, you'll likely want at least one party member who provides a lot of weapon damage. Crowd control should be a high priority as well since the enemies list for this mission includes a lot of Phantoms, and there's a final boss against whom anti-shield powers will come in very handy. EDI's Overload and Decoy can both prove very useful; the Neural Shock evolution of Overload is recommended as well as its Chain evolutions, allowing a single Overload to knock down up to three unshielded foot soldiers (though not Phantoms). Consider putting EDI in her "Power Recharge Time -25%" outfit.

Your second squadmate should be chosen based on which combat strengths Shepard and EDI don't provide enough of. Alternatively, consider bringing along your love interest if you have one, as there is an opportunity to hear some unique romance-specific dialogue on this mission.


Shuttle Bay[]

With fast reflexes the Atlas pictured can be hijacked

You'll land in a hangar bay for one of the hardest fights of the mission: standard Assault Troopers, Centurions and an Atlas Mech will flood in from in front and the right, while a Nemesis sniper camps out above on the left of the upper balconies encircling the hangar, which also happens to be where you eventually need to go to prevent Cerberus from depressurizing the hangar and blowing your entire squad out into space. First thing's first though: order your squad into cover ASAP and clear the immediate area of hostiles. A good place to hide is to the left behind the shuttle.

Tip: If you are fast enough, it is possible to snipe the pilot before he finishes climbing into the Atlas; this tactic is easier with an Infiltrator who can cloak and run forward heedless of enemy fire to set up the shot and also benefit from the cloak's damage bonus. An easier option is to use biotics—Pull or Singularity will stop the pilot. As for Vanguards, a biotic Charge towards the pilot saves the most time and puts you well within Atlas-hijacking distance. The fight is much easier when you have the Atlas at full health.

Warning: During this fight, Cerberus fighters continue to be launched at regular intervals from a catapult device in front of you. If you're too close to the path of the fighter as it blasts out of the hangar bay, it will heavily damage you. The sounds of the imminent launch can clue you in to when to expect this even if your sight is blocked.

Even if you can't jack the Atlas or prevent it from being manned, if you have Sabotage available just turn it to your side; otherwise take it out. A Javelin or other sniper or assault rifle equipped with the right scope mod can be useful here to see through the numerous smoke screens laid down by Centurions, but otherwise just wait them out. Your squad isn't affected by smoke so they should be able to fire without interruption. Use EDI's Decoy to draw fire if you need pressure taken off your team. Once the enemies have been thinned out, EDI will warn you of Cerberus' plan to vent the hangar and tells you to find a control that she can access to override this. Climb up the long ladder on the left to find it.

Warning: There is a time period of about 85 seconds from completing the initial battle to the activation of the hangar venting sequence. A Critical Mission Failure will occur if you fail to disable the venting sequence from the upper level terminal in time, even if you happen to be in the middle of the disabling cutscene at that moment.

Up on the balcony, there's nothing in the little chamber to the left but thermal clips, so turn right and head through the door. After the cutscene, be ready for Cerberus to storm into the room at fairly close range with several Guardians. You'll then have to fight your way around to the balcony on the other side of the room to use the "Rotation Controls". Look for a medical station in a dark room opposite to the "Rotation Controls" console for XP. Go through the next sets of doors, then, before heading down the ladder, go through another door to activate a PDA for 5,000 credits.

There's enough mechs and firepower for the entire squad, but nope, we have to slog the mission out on foot

Take the ladder down and operate the console to your right, the one with the ostentatious red bars like a jukebox. Admire the boom, and then get ready to fight the Atlas you saw in the cinematic. In addition to that one, there are two more (empty) Atlases in side alcoves on the left and right sides of the room. Two Troopers drop down from above and will attempt to man them; it's a good idea to take them out or disable them before doing anything else. The Atlas on the right is most easily hijacked if you want to risk making a dash for it—once inside, kill the soldier attempting to grab the left-side mech before turning your attention to the first enemy Atlas if it's still around.

Through the Smoking Hole[]

Hop the wall in front of the gaping hole left by the fighter and then before taking the door on the left, snag the M-37 Falcon; you can also use this as an opportunity to change your squad's equipped weapons (though not mods) if you wish. EDI must hack the door for you to enter and a short conversation ensues that confirms the value of having her along as well as previews the upcoming obstacles.

Through the door, there will be a ladder that will take you straight into another fight, so be ready. Once down, immediately sprint for cover, as Cerberus troops are waiting for you. You can flank by going forward from the ladder and taking the loop around and back, but you may run smack-dab into the Nemesis covering the area. Once you've cleared the hostiles, find a medi-gel dispenser and salvage a terminal for 5,000 credits on the far side near the ammo box to the left of the ladder you need to climb. While shopping, listen to EDI and your other companion discuss Cerberus tactics.

200 years into the future, data wiping software still do not work as advertised

In the next room, you will find the first of four video terminals viewable during this mission. The first two consoles give you insight into two of Cerberus's biggest programs: the Lazarus Project, and EDI herself. While not required objectives, the information on them reveals much about both the Lazarus Project and events immediately following Mass Effect 2. If you have a love interest and they are in your party, they will have some personal things to share with you at the Lazarus Project console. Don't miss the Serrice Council Greaves in that room as well.

Penetrate Combat Engineer Defenses[]

Once you're done with this first terminal, head out and into the burning section. There'll be a drop, after which you should turn right; it's another spot where the way forward isn't visible until you're already taking it. You'll immediately be flung into a fairly challenging fight with a bunch of Combat Engineers, Turrets and Shield Pylons all supporting each other in deadly combination. Take this battle slowly and carefully.

They're really going all-out with the defense

Tech abilities and Power Combos definitely come in quite handy here, as can grenades and weapons that deal explosive area damage such as the Venom Shotgun as they can easily destroy Shield Pylons with collateral damage. Overload (and its cousin Energy Drain) will destroy a Shield Pylon in one hit, and Sabotage used against the pylons or their generators can turn them against Cerberus, draining all shields in range instead of recharging them (use caution, as this can also work against your party's shields as well). Sabotage can also hack Turrets, making your life much easier. As you near the end, be prepared to deal with more smoke from several Centurions that drop in from the ladder that is also your exit out of here.

The top of the ladder yields another lore console, this time revealing that EDI started out as the foe in UNC: Rogue VI. If you never completed Grissom Academy: Emergency Evacuation, a datapad on one of the operating tables in this ominously bloodstained room will play an audio log of a captured Jack (if she survived the suicide mission) being tortured by a Cerberus operative. Go through the door, find a medical station and salvage 5,000 credits from a PDA.

As EDI hacks open the next door, you'll have a short radio conversation with Hackett where you convince him not to have the Alliance forces pull any punches in taking out Cerberus. Once through, go across the hall, ignoring for a moment the glowing blue hole in the wall, to find a Medkit, a Delumcore Overlay and the third lore console, this one about Kai Leng. At this point the base will begin to tremble under the assault from the Alliance Fifth Fleet, which elicits a comment from your squad. Once done, backtrack to the blue-lit hole and jump down.

The Human-Reaper Remains[]

Why couldn't Cerberus just let sleeping dogs lie

On the other side of the drop, you will find the remains of the Human-Reaper Larva that served as the final boss of Mass Effect 2. If you destroyed the Collector Base, only its heart will be present; if you spared it, much more of it will be there.

You must now fight your way up the catwalk surrounding the larva's corpse. There are Nemeses, Phantoms and really inconveniently-placed Shield Pylons. Take it slow, keep your shields up and don't be afraid to backtrack: things you can't hit from your current position may be open to other angles of attack.

Combat Tip: If you retreat as soon as the first Phantom enters (once you step on the inclined portion of the gangway after the cutscene) and take it out reasonably quickly, no additional enemies should spawn. Even if you don't exploit this, there is a small area behind where you dropped down that has decent cover positions including a tiny cul-de-sac behind a low barrier where Phantoms can't reach you.

There is the possibility of confronting two named enemies. If Shepard chose to turn Legion over to Cerberus after its acquisition during the Reaper IFF mission in Mass Effect 2, it will appear here as a unique enemy. Furthermore, if Shepard did not complete Grissom Academy: Emergency Evacuation, an indoctrinated Jack will appear here as a unique Phantom. Both characters must be fought and killed if met under these circumstances.

The Illusive Man's Inner Sanctum[]

Illusive Man yet again advocating control

After going up a final ladder after all enemies have been defeated you will be facing an open doorway. Before going through, you can find a medkit and 5,000 credit PDA behind you at the end of the catwalk. Through the door, you'll find yourself in a hallway with multiple computer terminals on either side. To the left you will find an ammo box, another medkit and a final PDA worth 5,000 credits surrounded by scattered cigarette butts. Nearby is another video log where you can learn some chilling details about Cerberus Reaper implants. The door at the end of the hall leads to a dark, cavernous room, empty save for a ramp leading up to a final door. Before entering you may wish to save, as beyond it lies the Illusive Man's inner sanctum, a location the player will undoubtedly recognize.

Entering this room initiates a third meeting between Shepard and the Illusive Man, who, as usual, appears via hologram. As before the Illusive Man speaks of controlling the Reapers. The player is presented with a series of dialogue choices and can either attempt to convince the Illusive Man that his plan won't work, or threaten and berate him for his actions. As in the previous conversations with him, it is possible to use Charm or Intimidate options which can have important consequences later. For now, no matter what you say the Cerberus mastermind remains as implacable as ever, and he cuts off communication just as your team finds the Prothean VI with a final threat to not "overstay your welcome."

Vendetta finally reveals the nature of the Catalyst: it is the Citadel! Unfortunately, as the Illusive Man successfully overrode Vendetta's security protocols, he also knows what the Catalyst is. Worse still, he has fled to the Citadel and alerted the Reapers, which have taken control of the Citadel and moved it to the heart of their occupied territory: Earth.

Defeat Kai Leng[]

Before any action can be taken, however, Kai Leng shows up, bent on settling his score with you. You are undoubtedly just as eager to deliver some payback. Get ready: only one of you is going to be walking away from this alive.

It's not a traditional bossfight without periodically summoned minions rushing to aid the boss

The Illusive Man's sanctum is now a battlefield. Leng makes a show of destroying the floor in front of him, gouging out some cover opportunities in the featureless room. As soon as the cutscene ends you may need to use your melee attack immediately because Kai Leng will be on top of you and you'll have to fend him off. You can also do a quick combat roll to the side or behind to avoid close quarters grappling, though you or your squad has to do some damage to Leng to force him to stop chasing after you. After the opening moments of the fight, take cover with your squad in the pit Leng opened in the floor near where you entered from, facing the Illusive Man's chair. Stay on the right with your squad to your left.

Leng's health can't be damaged early on in the fight, and he's immune to most crowd control abilities though he can be slowed by cryo powers. He also uses occasional heavy-melee attacks if you allow him to get close. These attacks can kill you instantly unless you block them by tapping melee. Unless you're a close-range specialist, it's better to keep Kai Leng at a safe distance by distracting him, running away, or dealing severe damage to his shields which makes him retreat.

PROTIP: Shoot out the minions as they descend, or just Lash them into irrelevance if you have the power

When Kai Leng takes heavy damage to his shields he will stop attacking, then run towards specific points in the room, yell, and punch new holes in the floor, creating more places to take cover. Unlike Leng's first floor punch, the ceiling above him gets destroyed too. During these pauses his shields recharge, he becomes temporarily immune to damage, and a wave of Cerberus minions drops in from the holes in the ceiling. He will do this three times.

In the first wave Leng destroys the floor behind the holo terminals, and summons 4 Assault Troopers. In the second wave Leng destroys the floor to the right side of the room, and dropping from the ceiling are 1 Nemesis sniper and 3 Troopers. In the third wave Leng demolishes the floor on the left side and 2 Phantoms drop in. The Phantoms signal the final stage of the fight—once they appear Leng himself can finally be taken out.

Space ninjas gotta pose like edgy posers even in the face of certain defeat

Phantoms and the Nemesis in that order are usually the greatest threats when they're on the field though, so generally take them out first. Apart from that, you can either focus on Leng to drive him off if he approaches, or pick off all the Troopers to minimize incoming grenades. EDI's Decoy can be quite useful here as it draws attention from every enemy including Leng himself. Once Leng and all his minions are down, the fight ends. Note: see bugs below if you find yourself stuck.

After he's defeated, there will be a Renegade interrupt opportunity as Leng sneaks up on you and attempts to stab you. If you don't use the interrupt, Shepard will dodge; if you do, Shepard will block the blade and shatter it. In either case, Shepard follows up with a vicious omni-blade attack—along with some choice words—putting an end to Kai Leng once and for all.

You will then have a last conversation with the Prothean VI with an option for a Renegade interrupt, or if you wait, a Paragon one. Finally, you will return to the Normandy for a debrief with Anderson.


Seems Vendetta has no vendetta against synthetics unlike his creators

Admiral Anderson confirms that the Citadel is now in orbit of Earth, and Priority: Earth becomes available. Note that no other system is available for visitation at this point; the only system you can travel to is Sol.

Warning: Unlike for most missions, merely traveling to the system triggers Priority: Earth without an opportunity to back out.

Until you're ready to return to Earth for the final battle, you still have free run of the Normandy herself, and you should feel free to check in with the crew and hear any final comments they might have. Visit Cortez's shopping depot to make any last purchases. Do Mass Effect 3: Galaxy at War activities if you need some last-minute buffing of your War Assets. Note that you've received either the Reaper Heart (100) or the Reaper Brain (110) as War Assets augmenting the Crucible. Legendary Edition: the Galaxy at War system is not in Mass Effect Legendary Edition and War Asset numbers are treated as if Galactic Readiness is at 100%.

If she's still on the ship, talk to Diana Allers and then check your e-mail for a final message from her.

Finally, if you did not romance Tali or Garrus, make sure to check the gunnery room to catch them "in the act". Otherwise, they will still be there, but wagering on which one will kill more Reaper troops.



  • Multiple players have encountered a condition where they killed Kai Leng relatively suddenly, and all other enemies then disappeared and they were stuck in limbo with no way to advance the plot. This likely represents the failure of the cutscene to fire, but whether this occurs because of the speed of the kill or merely from e.g. a coincidental lack of memory resources on the players machine is not known. In any event, if it happens, you'll have to back up to a saved game.


  • Some players have reported seeing Kai Leng move his head, rather obviously, just as the scene ends and Shepard is walking away.
  • According to former cinematic designer Violet McVinnie, Kai Leng was originally slated to die in combat. She advocated for the sequence where Leng attempts a sneak attack, only for the player to be presented with an interrupt option to stab him.[1]


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