Lya is one of the Nox first met in the episode, 1.08 "The Nox", and became a close friend of the members of SG-1.
Lya was one of the Nox that met SG-1 when they first arrived on the Nox homeworld, P3X-774 (1.08 "The Nox"). She and her fellow Nox brought three of SG-1 back from the dead when they were killed during a battle with Apophis. She and her fellows tried to explain their peaceful ways to the team, but were rebuffed as naive by the team, who did not realize the Nox's true advanced nature.
Lya was concerned that Teal'c bound the Jaffa Shak'l, but was sharp enough to note that Shak'l was feigning unconsciousness. Later she unwittingly was used as a distraction. Shak'l screamed as if Teal'c was hurting him. When she came to investigate, Shak'l used Teal'c's lapse in concentration to reveal a hidden weapon, stabbing Teal'c and killing Lya.
Lya was revived by the Nox Ritual of Life. Even after this example of Goa'uld treachery, she and the other Nox refused to allow SG-1 to attack Apophis and the other Goa'uld. She became concerned when the Nox child, Nafrayu, went missing, and assisted in the Ritual of Life to revive him.
Several months later, Lya went to Earth (1.17 "Enigma"). The Nox responded to a message requesting sanctuary for some Tollan refugees led by Omoc. Lya came to offer them welcome. A frantic Colonel Maybourne ordered the guards in the gateroom to fire, but Lya made all their weapons disappear. She was disappointed the humans had learned nothing, but noted Daniel Jackson at least had.
When the Tollan requested a Nox come to be part of a Triad (trial), Lya arrived to the new Tollan homeworld, Tollana (3.15 "Pretense"). There she was a neutral "archon" or advocate, to determine whether the Goa'uld Klorel should retain control of his host, or if Skaara should be freed. Lya was moved by Skaara's heartfelt testimony and ruled in favor of "the original owner" of that body, thus casting the deciding vote in Skaara's favor.
During the course of the trial, SG-1 (Skaara's archon) was suspicious Zipacna (Klorel's archon) had ulterior motives besides the triad. Teal'c convinced her to use her Nox cloaking powers to hide one of the Tollan defense cannons. If the Goa'uld did nothing, it would mean nothing. If they attacked, one weapon would not be damaged. Lya's actions saved Tollana from destruction. She later admitted to SG-1 that by hiding the weapon, she was treading close to the fine line of pacifism followed by the Nox.
--Aurora 20:41, 2 September 2007 (PDT)