Mass Effect 3 Walkthrough Part 77: Priority: Cerberus Headquarters Part 3

After leaving the Reaper dangling from the facility’s ceiling, head towards the walkways and prepare for another battle. This time, you will have to contend with Assault Troopers, Phantoms, and Nemeses all in the same little area. Run to the left when you get onto the catwalks. The Phantoms will be the most dangerous enemies here, so try to kill them first. Use the narrow confines of the catwalks to force the Phantoms to take you on from the front. Hit them with something like Shockwave or Biotic Charge to make them visible when they cloak, or use a Shotgun when they get close enough to you. You should be able to kill them easily enough this way. Just watch out for the telltale glow of the Nemeses Sniper Rifles.

Next will come the Nemesis snipers. They will be attempting to target you from afar this whole time, so take cover after mowing down the Phantoms and take out your Sniper Rifle. If you don’t have one, and Garrus is in your party, feel free to have him deal with the problem while you take on the other enemies. Otherwise, counter-snipe the Nemeses and take out your Assault Rifle, Pistol, SMG, or Shotgun to deal with the remaining Assault Troopers. Watch out behind you, as just when the enemy numbers seem to be dwindling, a few reinforcements will come up from your back side in an attempt to flank you. Same goes for the series of catwalks below you, which the Assault Troopers will likely try to use to flank behind you. Position one squad-mate on the stairs by the lower catwalks to guard your back from there, and the other squad-mate behind you so that the inevitable wave of reinforcements doesn’t take you by surprise.

The most unsettling part of this battle can be the way that it will use your own allies against you. If you did not complete certain missions, or if you made certain decisions in Mass Effect 2, you will have to contend with your own ex-squad members. If you neglected to take on the Grissom Academy mission earlier in the game, you will have noted the PDA earlier in the base saying that the Cerberus soldiers were able to overpower Jack at the school and bring her to the facility. Well during this battle, you will have to face Jack, only in Phantom form, if she suffered this cruel fate. The same goes for Legion, who will be turned against you here if you sold him to the Illusive Man in Mass Effect 2. Legion will be even more fearsome a warrior than he was on your ship, having been transformed into a sort of perfect synthetic assassin by the Illusive Man.

When you are done cleaning up on the catwalks, run to their end and climb the ladder that you will find there. You will find more Cerberus troops waiting for you up here. You will be fighting in much closer quarters, so use charge melee attacks, Shotguns, and Biotics like Nova to clear out the area quickly. You will have to reach the ladder on the other side of the catwalks. Kill off all of the enemies, using the cover to the sides of the walkway if necessary, and proceed to the ladder. Climb up. When you reach the top of the ladder, turn to the left to reach a new room. Here, you will find another video log that you can watch. This series of videos covers a man named Paul Grayson, who used to work for Cerberus, and whose story is told in the Mass Effect novels.

After the videos are over, search the area to find some items, including Medi-Gels and a PDA to the left of the console, and another PDA and more Medi-Gels down the walkway, on the opposite side of the catwalk as the room you are in right now. Enter the pause menu and level your party up if necessary, and prepare to face a boss battle. First, however, you will have to investigate the Illusive Man’s office. Head through the only door to reach the ethereal office of the Cerberus leader.

Unfortunately, the room will be empty when you walk in. The Illusive Man will have already escaped, having gotten word of your presence early on in the attack. He will show up in hologram form, however, when you try to find the stolen Prothean VI. Ask the Illusive Man about the Catalyst and what it is. He will refuse to answer your question directly, and instead he will suggest that you speak with the Prothean VI yourself to figure that one out. With this, he will summon the VI to speak with you. You can keep this conversation going to try to change the Illusive Man’s mind about fighting the Reapers yet again, but of course it will be of no use. Simply ask the remaining questions, and use them as a way to increase your Paragon or Renegade rating. When you are done speaking with the Illusive Man, turn your attention to questioning the Prothean VI.

This will prove to be a much more fruitful conversation. The Prothean VI will explain to you exactly what the Catalyst is and how it works within the overall context of the Crucible. He will explain how the power of both of these forces combined will actually be enough to defeat the Reapers for good. Then, he will deliver some truly disturbing news. Apparently the Illusive Man, foreseeing your attack on his base, has already told the Reapers about the Catalyst and the Crucible. The Reapers, then, have already moved to take control of the Catalyst. You will simply have to break free of the Cerberus base, fly to Earth, and hope to take the Catalyst back. Of course, matters are never as simple as they sound, and Kai Leng has to sate his thirst for blood somehow, so you will be manipulated into a boss battle against him, here in the Illusive Man’s office.