Called "the Destroyer of Worlds" by her people, destruction and death follow the unstable and unethical scientist Linea. Extremely intelligent, she developed a pathogen that wiped out an enormous number of her people. She was sent to the prison colony Hadante for her crimes, and was even feared by the other prisoners there.
Linea remained on Hadante until SG-1, unjustly convicted of a crime, arrived. They possessed the knowledge to reactivate the Stargate from Hadante's end, and, in exchange for her ability to provide a power source, she won her freedom. While on Earth, she learned that the Stargate can travel to thousands of worlds, and forcibly left the S.G.C. after programming the base computer to indicate that it was about to self-destruct the base.
Linea travelled to the planet Vyus, where she began her terrible experiments again. This time, experiments in an eternal youth treatment caused a disaster that the people of Vyus came to call the "Vorlix." The entire population regressed in age and lost their memories. Linea was subject to this transformation as well, and forgot the monster she was. Now taking on the name of Ke'ra, she is as clueless as anyone else in the population.
It is only after SG-1 arrived that she learned who she truly is, using her natural brilliance to help find a cure for the memory loss. After remembering who she was, Linea tried to kill herself -- but was stopped by Daniel Jackson. With help from the S.G.C., she successfully lost her memories once again and returned to Vyus to live out her life as Ke'ra.
(SG1:Prisioners)