Dr. Liara T'Soni is an Asari scientist with powerful biotic abilities and an expert on Prothean artifacts. She is a possible romantic interest for Commander Shepard. While a party member in the first Mass Effect, she has only a minor role in Mass Effect 2, although she joins your party again in the Shadow Broker DLC mission and Mass Effect 3.
Liara's likeness is based on Jillian Murray, while her voice was provided by Ali Hillis.
Liara was born in 2077, 106 years before the first game starts, and is the daughter of Matriarch Benezia and an unknown Asari. Procreation between Asari is frowned upon, as no new genetic information is added to the species; offspring from such a bonding are sometimes referred to by the highly offensive label 'Pureblood'. Because of this, Liara was raised only by Benezia and knows very little about her “father”. She had a distant relationship with her powerful mother, daunted by the pressure of living up to her reputation. She became interested in scientific and historical investigation, in part because it allowed her to work alone and not follow in her mothers' footsteps.
Mass Effect 1
Commander Shepard first encounters Liara at a Prothean dig site on Therum, where she is trapped inside a defense barrier. Because of her relationship with Benezia, who is now working for Saren, Shepard initially believes Liara might have useful information. However it quickly becomes clear that she is uninvolved with her mother, and she joins the crew of the Normandy. In combat, she is a very effective biotic, having similar abilities to the Adept class.
If Liara is brought on the mission to Noveria, she will assure Shepard that her relationship with Benezia will not endanger the mission. When confronting Benezia, extra dialogue between the two will occur.
Additionally, if Liara is not rescued until after all the other possible missions are completed, she will have suffered from the prolonged imprisonment and will suspect Shepard of being a hallucination.
Liara can become romantically involved with Shepard. Because Asari are mono-gendered, this can occur regardless of whether Shepard is male or female. Because of her lack of experience in social situations, especially with humans, she is initially awkward onboard the Normandy. Gradually, she develops an interest in Shepard beyond his connection with the Protheans, and an intimate relationship can occur if the player so chooses.
The Search for Shepard (Mass Effect: Redemption)
After the disappearance of Commander Shepard in the Collector attack, Liara embarks on a search for him. Eventually, Cerberus reveals to her that the Collectors have hired the Shadow Broker to find and retrieve Shepard's body. She reluctantly agrees to work with Cerberus against the Shadow Broker, knowing that this is the best chance Shepard has to survive.
Mass Effect 2
After her encounters with the Shadow Broker, Liara decides to seek vengeance and in the process becomes an information broker herself. No longer the timid researcher, she displays much more confidence, as well as more willingness to engage in violent or illegal actions for her own purposes. Although she is glad Shepard is alive, her preoccupation with the Shadow Broker prevents her from joining his crew again, meaning she is no longer a party member.
Lair of The Shadow Broker DLC
The Illusive Man provides Shepard with information regarding the whereabouts of the Shadow Broker , and he in turn passes it on to Liara. However, shortly thereafter an attempt is made on Liara's life, and she disappears. Shepard joins with another Spectre to investigate. Shepard and Liara are eventually reunited, and together they set out to overthrow the Shadow Broker once and for all. Liara becomes a companion again (although only for this mission), and any romantic relationships with her can be continued.
Mass Effect 3
Liara returns as an active squad member in Mass Effect 3, meeting near the beginning of the game when investigating the Mars Archives for information that could potentially be used to stop the Reaper invasion. Liara joins you shortly after the start of the mission and remains as a squadmate for the remainder of the game. She is also available as a romance option for either a male of female Shepard.
If the player did not play through the events of Lair of the Shadow Broker, Liara will explain that she raided the Broker's base herself with the help of dozens of hired mercs, but that Feron was killed in the process. After being tracked down by Cerberus, she crashed the Broker's ship into a Cerberus cruiser to make her escape, salvaging only vital equipment. She then sets up her office onboard the Normandy.