When talking to Liara, ask if she needs help with her problem. This is a quest that will net you Renegade points, but if you want 100 percent completion you don't have a choice. Liara wants you to disable security in certain areas to create a glitch allowing access to data potentially revealing vital data about a mysterious agent known only as the Observer. You will then need to use a server nearby to physically get the information.
You can find the first set of terminals in the transport area, the same location where you caught the taxi to find the Justicar. Hack each one you find and a time limit will appear. You then have to use the radar-like signal to get close to the paired terminal. Usually it’s just the nearest computer to the first one. When you come into the transport hub the first terminal is immediately to your right, with the other two near the weapons shop.
With all of these done, Liara wants to talk to you later. You now need to go off and do another mission before this one can proceed any further. Once returned, go to speak to Liara in her office. She wants to know who the ‘Observer’ is, and has armed assassins ready to take out a person at your request. This will earn you Renegade points and they are unavoidable if you see this part of the side quest through. To discover the Observer’s identity, you need to head to the Trading Floor and hack the terminals there. Each of these will give you hints to reveal your answer. There are terminals at the bottom of the stairs going to Liara’s office, in the Eternity Bar, by the corridor leading to the trading area, and next to the upgrades stand.
You may struggle to make sense of the hints within these terminals. That is because none of these were really the killer – Liara will eliminate the wrong target if you give her misleading information. Say that none of the names she supplied are the Observer, and another conclusion will be reached.
Upon entry into the Eternity bar you will come across a Quarian and Asari. The former is the slave of the latter, but she doesn't mind as it's a very different prospect on Illium than elsewhere. Her contract was up for sale, but the company interested in buying it has changed its mind. You should talk to the company representative on the bar's veranda, making the benefits of buying a slave and then freeing it for the company's image clear. Alternatively, talk to the Asari that currently owns the Quarian's contract and convince her to let her go. Or, just ignore the slave's problems for some Renegade points!
Help out the slave.
Near the hallway from the trading floor to the Shipping department and Liara's office is a human Shepard knows from his past. She is now in control of an operation investigating an Asari businesswoman believed to be selling illegal schematics. She wants your help to catch her, so having spoken to her and received the secret message, approach the Asari at her stall towards the back of the trading floor. Use your persuasive conversation to get her to spill about the designs and Gianna will come in to catch her in the act. Speak to Gianna back at her table and ask any more questions you want to and complete the quest.
In the Transport Hub sitting on a bench outside Officer Dara's office is a woman from Feros in the first game. You saved her life before, but now she needs your help again. Medical investigations into the effect of the Thorian's control on the colonists led to a contract which allows the medical company to perform invasive procedures without the colonists' consent. While the company can't actually operate on them, it would force a breach of contract which the colony cannot afford. Speak to the Baria Frontiers representative at the top of the Transportation Hub near their shop terminal (she should be straight ahead when you finish your conversation).
Deal with the medical contractor.
When the opportunity presents itself, choose the Paragon or Renegade conversation options to convince the rep of her mistake. Return to Shiala to inform her of your success to complete the quest. (Note that it now may be a good time to buy the star charts from the Baria Frontiers shop as you need these to complete every side-quest and exploration mission in the game!).
Blue Rose of Illium
Also in the Transportation Hub you will find an Asari clearly in some distress (she's standing against the wall of the taxi rank, on the opposite side of the hub to the Baria Frontiers rep. She is having problems with her hubby's constant attempts to woo her with poetry. And her boyfriend is a Krogan, which makes things even more hilarious. He wants children, but the Asari thinks that this is just to continue his line rather than because he loves her. Make your decision (with the obvious Paragon or Renegade implications) and she will take your advice to heart. You also get a discount at her shop (Memories of Illium, selling fish and model ships).
Get her to date or dump the lovable Krogan.
Lost Locket Found
There is an Asari just to the left of the corridor to the lobby and Normandy dock when you emerge outside at Illium. She is near the vista spot where Miranda can comment on the view. You must have completed Miranda's loyalty quest and collected the locket at the end of the boss-fight. Hand it to the Asari to make her day.
The Salarian that is always on the phone on the way to the shipping department of Illium has lost a datapad. You can find it during the recruitment mission for Thane the assassin. Return it to its rightful owner for a suitable reward.
During the Justicar recruitment quest you will locate a Shipping Manifest towards the end of the level. You can give it to Pitne For to aid a criminal, or turn it over to Detective Anaya for Paragon points.
Stolen Goods Found
During the Justicar recruitment quest, pick up the data just as you enter the crime-scene. If you choose to release the information you receive Renegade points as Thrax, who the items were stolen from, is a criminal. Keep it hidden and this does not occur. If you made it public, next time you return to Illium a representative of Thrax will approach you with his thanks and a reward.
Packages for Ish
If you have spoken to the Salarian Ish on Omega (see Omega walkthrough), he will have asked you to collect two Datapads of information for him. One is on Illium, resting on seat at the back of the Eternity bar. Collect it while you are on Illium if you want to help. To hand in the package, return to Ish on Omega.
The location of the Datapad in Illium's Eternity Bar