Lantean military officer, first officer of the Ancient warship Aurora. According to the Aurora's captain she was his trusted right hand for many years. Trebal and the rest of the crew were dispatched by the Atlantis high council to the outer reaches of the Pegasus Galaxy to gain any and all information pertaining to a weakness in Wraith defenses.
Trebal was killed by a Wraith when she was forcibly removed from her stasis pod. The Wraith then assumed her identity within the artificial environment that networked the minds of the ship's crew, intent on learning the secrets of the Ancients' intergalactic hyperdrive technology.
Aurora - Teyla and Dex find the body of the deceased Trebal and soon discover that a Wraith has entered the virtual environment in her stead.