Serving as an assistant to the Red Sith Ravilan Wroth circa 4985 BBY, Ravilan's aide was a Human female belonging to the Lost Tribe of Sith. Seelah Korsin referred to her as either "Yilanna" or "Illyana".
This Human female aide of Ravilan's, originally from the Sith Empire, found herself assigned to the starship Omen. The mission: mine Lignan ore in preparation for the impending Battle of Kirrek during the Great Hyperspace War. During a hyperspace jump, Omen collided with its sister ship, the Harbinger. This occurred after a Jedi starfighter attack forced Omen to retreat in order to safeguard the mined Lignan. Like the other members of the Lost Tribe of Sith, she ended up crash-landing on the planet Kesh aboard the Sith dreadnaught Omen, becoming one of the god–like Skyborn figures in native's legends.
After fifteen years on Kesh, and in her forties, she accompanied the Red Sith Ravilan Wroth to Tetsubal, a village situated on the Ragnos Lakes. Their purpose was to investigate a fluorescent algae for potential use in illuminating Sith structures. However, Ravilan and his followers, known as the Fifty-seven, secretly and deliberately instigated a plague by introducing the poisonous cyanogen silicate into the water supply. This was an attempt to frighten the Sith on Kesh into prioritizing their departure from the planet. Ravilan's aide, along with approximately eighteen thousand Keshiri natives, perished due to the toxin. When her body was discovered by Sith investigators, Seelah Korsin, wife of the leader and Grand Lord Yaru Korsin, identified the swollen, blue discoloration of her tongue as a consequence of the cyanogen silicate. This observation led Seelah to deduce Ravilan's involvement, ultimately resulting in the Grand Lord's order to kill all Red Sith on Kesh, including Ravilan.
The Human Sith aide to Ravilan was initially presented in John Jackson Miller's eBook Lost Tribe of the Sith: Paragon. Her appearance was limited to her deceased form, having been poisoned by cyanogen silicate.