Dossier: The Assassin is a Mission in Mass Effect 2Dossier: The Assassin is one of the three Dossiers the Illusive Man hands you after completing Horizon. Missions in Mass Effect 2 need to be completed in order to progress the story forward, and unravel the mysteries about the Reapers.


General Information

  • Previous: Horizon
  • Next: __next__
  • Bosses:  N/A


Video Walkthrough

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NPCs in the area


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Full Dossier: The Assassin Walkthrough

Getting Ready

You will face a lot of Enemies during this Dossier, so try to bring a balanced team. Specially, bring someone that can use Warp, Warp Ammo or Overload. There are some Mechs also to face, so AI Hacking can be useful too. 


Travel to Illium, located in the Tasale system, within the Crescent Nebula cluster to begin tracking the assassin. Once you reach the aforementioned planet, you will be welcomed by Careena, a Nos Astra official. She tells you that all administrative formalities and docking fees have been taken care of by a former member of the Normandy Crew, Liara T'Soni. Careena also expresses that Liara is waiting for you patiently in her office. 

Once you reach her office, Liara tells you that Thane Krios arrived a few days ago on Illium, and is targeting Nassana Dantius. (You may remember if you completed her Assignment in the original Mass Effect). Apparently, Thane contacted an Asari called Seryna, who has an office in the cargo transfer levels, so that should be your next objective.

When you reach the office, you learn that Seryna used to be Nassana Dantius' head of security, but her way of business rivals or political figures by assassination wasn't something Seryna approved, and when she finally confronted Nassana about those actions, she decided to relieve her of her job.

Seryna tells you that Nassana resides in the penthouse of Tower One of the Dantius Towers. She believes that Thane is planning to infiltrate through the second tower, which is still under construction. Seryna can take you to the Dantius Towers, however if you go, you won't be able to return Nos Astra until the Mission is completed.

If you are ready, agree to go and a cutscene will play out, in which Seryna details Nassana's paranoia regarding killers. Once dropped off at the bottom of the still empty tower, you will find a bunch of security mechs chasing Salarian contruction workers. Get everything ready, as they won't engage you until you attack them, so you can prepare your ammo or Powers.

Destroy them and check the room to the left where you can find Medi-Gel and a hackable Terminal that can be looted for x4800 Credits. You can talk to a wounded Salarian for information. He explains that Nassana sent the mechs to get rid of all the night workers. You can use a Paragon interrupt to use some Medi-Gel, making him give you more information about how to tackle the trip through the tower.

Now head through the door and down the hall. As soon as you exit it, take cover, you will find Eclipse mercs and Mechs. This is the first one of a long series of fights around a U-shaped level. Take cover and you will face...24 Enemies. Eliminate them as they come along. Be careful of flanking Enemies, because mercs tend to behave like that frequently. 

Send your squad ahead of you at each of the corners, but keep them in cover nonetheless. As long as you move forward slowly, there will be several breaks between waves of Enemies, this allows for any downed teammate to be revived for free.

Try to focus on the Mechs first in each wave, as they are the only Enemies that will attempt to approach you at close range. Prioritize the FENRIS Mechs first and then the LOKI Mechs.

After you round the second corner, you will find two corridors that the Eclipse mercs will be attacking from. One of them has cover and the other one doesn't. You can use your squad to pin down the mercs and then go yourself to flank them and reach the ramp at the end of the level. When you finally reach the end of the corridor, head up the ramp to level 2.

You will find two med-kits containing Medi-Gel at the top of a ramp and thermal clips. Take the items and take cover, as there will be more Eclipse mercs. You will encounter four waves of mercs coming along the corridors and rooms of the level. Each wave is composed of four mechs, five shielded mercs and an Eclipse Vanguard with barriers. Between waves, you will have a moment to replenish your ammo, reposition, etc.

Again, it is best to take out the mechs first. Always take cover to prevent being overwhelmed by Enemies, because they will come from two different sides. You have two options now, either go straight up the hall, taking on the waves of Enemies head-on, or take the door back and to the right to reach a fairly safe flanking position. This option separates you from your squad.

Once the mercs are down, gather clips, reload and wait for shields and Powers to recover. You can also find a med-kit containing a Medi-Gel just after the two paths converge. Save your game, because the next area can get ugly.

Explore a little, but DON'T GO INTO THE ELEVATOR YET. To the other side from where you entered, down the hallway, you can find some power cells, a hackable terminal that grants you x4200 Credits and an M-97 Viper Sniper Rifle. Keep in mind that if you pick up the Viper, any squadmate with a Sniper Rifle will automatically change to it.

Now head back and bypass a nearby door. You will find Daroth and Shelum, two Salarian workers. They will tell you that someone locked them in the room, but it wasn't an Eclipse mercenary. You can earn some morality points during this conversation. You will find a Medi-Gel and a secure locker that contains x3000 Credits inside the room.

Now head to the elevator, before you open it, put your squad in cover. Activate the elevator, and take cover ASAP. A Krogan Bounty Hunter and two Eclipse Engineers will come out of the elevator. Using Heavy Weapons like the Arc Projector or the M-100 Grenade Launcher can be extremely helpful here, especially immediately after the elevator opens and the Enemies are all crowded together. Try to focus on the Engineers first, because they are weaker than the Krogan and by eliminating you eliminate the threat of facing the drones. 

Once all the Enemies are down, you have a moment to return for any Medi-gel you left in reserve, the M-97 Viper (if you want it now) and grab any ammo left. When you're ready, take the elevator up.

Exit the elevator and you will find an Eclipse Trooper communicating with his superiors, you interrupt him and you can obtain some information from him. You can use the Renegade Interruption to send the merc through the window. He will tell you how to get to Nassana and after that you can decide to either kill him or let him go. The Paragon option lets him leave peacefully, while the Renegade option ends in him calling more mercs to your position.

After the merc conversation, head over to grab a datapad from the floor. It contains the Kirosa Genetic database for the Salarian Family Data Assignment. Open either of the doors into the next room, which is large, open and has plenty of cover. If you decide to enter quietly, you can hear a conversation between Nassana and her hired help, she's obviously not happy about what is going on. Take cover and use Overload on the big explosive container if possible, and then focus on the FENRIS Mechs to prevent them from dislodging you from cover, then take care of the LOKI Mechs. After that, a wave of three mercs will come at you, dispose of them however you see fit.

Once you have taken care of the Eclipse Mercs, head to the door on the left side of the room and bypass it. Immediately after opening it a terrified Salarian will point a pistol at you. You can use a Renegade interrupt to punch the Salarian. No matter what you decided to do, the armed Salarian called Telon will fall unconscious and his brother, Chesith, will rush to aid him. He tells you about the treatment they received from the Eclipse Mercs, after you finish talking to him, you can grab a Medi-Gel from a med kit. and obtain x6000 Credits from a PDA, on an Eclipse mercenary corpse.

Now head back out, and before the ramps leading to the roof and bridge, you will find power cells, a comm terminal and a second M-97 Viper Sniper Rifle, in case you didn't take the one previously found. The comm terminal gives you options to annoy Nassana, but nothing else. Now take the roof and the bridge to Tower One.

Get into cover because there are flanking Enemies on your left. There are two Mechs and three Vanguards, so it can get messy. Use cover wisely to take them out one by one, and when all of them are gone, move to the pillars and crates on the opposite side of the entrance.

Take the crate to obtain x500 Element Zero and if you need new Weapons, use the weapons locker. Also don’t forget to pick up the med-kit with Medi-gel just to the left of the locker. Save your game if possible.

Move slowly and try to remain undetected while going around the corner. If you are able to shoot or overload the big explosive container, you'll do massive damage to the two mercs standing right by it. The room is little and there's not much room for maneuvrabiliy, and besides that, besides the Mechs and mercs there is also an Eclipse Vanguard and a powerful Eclipse Commando. Try to focus on one enemy at a time. 

Once the mercs are down go to the end to obtain a submachine gun upgrade, another med-kit with Medi-gel. There also another PDA on another dead Eclipse mercenary corpse, that can be hacked to obtain x12000 Credits.

The next ledge drops is the point of no return, so it is advised to save your game, check or change your Weapons, wait for Powers and shields to recover, loot everything, etc.

The bridge that leads to Tower One is a narrow walkway that is ideal for Sniper Rifles. You will find the usual suspects, Eclipse Mercs and Mechs. You can also use Powers to knock Enemies off for instant kills. Move from cover to cover on the bridge, until rockets start raining on you. You will see two stationary rocket drones at the end of the bridge, and they will start firing you before they become targetable by your Powers. Although they might be hard to target from that position, note that the Drones only have shields, and once they are down, the drones are gone. 

Once the bridge is cleared of Enemies, get into cover at the end of the bridge, because another wave of Enemies will appear on the upper level of the bridge leading to Tower One's penthouse. Try to take these guys out before you head up the stairs. Once they are down, send your squad up the stairs, but try to keep them close to the right, and equip a short range Weapon, because another Eclipse Commando, awaits as the last barrier to Nassana's penthouse. Try to fire from cover, and keep in mind that the Commando wields a Shotgun but won't follow you back down the stairs, so you can retreat to regenarte shields and health if necessary.

With the Commando gone, the combar part of the Mission is finally over. Enter the penthouse if you are ready. 

Open the door to find the last few remaining Eclipse mercs, tending to Nassana, raise their Weapons. When she sees you, she's shocked to see you alive. If you imported the save file from the original Mass Effect, there's more interaction with Nassana (If you completed her Assignment, in the previous game). She will ask you who has hired you to kill her, because she is sure that is your current assignment. Suddenly, a noise distracts the guards and Nassana tells them to go check all the other entrances to the Penthouse. Thane is waiting in the ventilation ducts for the right moment. Once the mercs have their backs to the windows, he makes his move.

The Drell jumps down from the ducts and kills one merc silently by snapping his neck, then he immediately kills another with a quick punch in the neck and proceeds to shoot the last of Nassana's mercs before he grabs her herself.

He shoves his pistol into Nassana's gut and pulls the trigger without hesitation at point-blank range, causing Nassana to slump dead. Thane  places her on the desk and folds her arms, before he starts praying. At this point, you can start speaking with Thane by choosing to be nice or angry that he is ignoring you.

He tells you that your actions on the second tower, provided a great distraction for him, allowing him to get further and faster than he had expected. You can tell him about the suicide Mission and the Collectors' threat, prompting him to join your side to face these challenges. He surprinsingly agrees without a doubt, stating that he is dying and wishes to make the universe a brighter place before his death. After ending the conversation, you will be automatically returned to the Normandy

Thane will be quartered in the Life Support section of the Normandy because it's the slightly more arid place of the ship




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Trivia & Notes

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