- "I sense a sickness in the Force […] I believe Darth Mekhis is here."
- ―Ngani Zho
Darth Mekhis, a scientist and Dark Lord of the Sith who served on the Dark Council in the resurgent Sith Empire, led the Sith forces in the Battle of Rhen Var, establishing a fortress as a command center until Satele Shan and her Republic forces arrived. Breaking open the door to Mekhis's chamber with the Force, Shan asked the Sith Lord to surrender and offered protection in exchange. However, Mekhis refused, and the two began a fierce duel that resulted in Mekhis being grievously injured before she escaped.
During the Cold War, Darth Mekhis served as a weapon designer working on projects to give the Sith the advantage when hostilities resumed, most of them produced at the Sun Razer facility she created to provide the resources to construct them. Mekhis designed a new and experimental class of warship called the Javelin Dreadnought, capable of using its weapons to flash irradiate a planet's surface from space, wiping out all life below within a three kilometer radius. She christened the prototype Ror'jhan, which meant "she-whose-leaves-sweat-poison" in the Sith language.
Darth Mekhis also had in her employ a legion of Sith Knights, semi-mechanical thralls created from captured Jedi and corrupted by her power. She was later seen aboard her Sun Razer in the Vesla system completing the last modification when the captain Eisek informed her of the capture of Theron Shan and Master Ngani Zho and she immediately ordered the execution of the Jedi Master. Things took an unexpected turn when the two of them escaped. Ngani eventually died, protecting the female Twi'lek Teff'ith from blaster shots. In the same time, Theron made his way to Mekhis, and after revealing his relation to Satele Shan to throw her off guard, defeated her using a toxicity-ten poison, leaving her on the Sun Razer as it exploded. Her rival, Darth Hadra, took her place on the Dark Council.
- Star Wars: The Old Republic (Mentioned only) (Codex entry)
- The Old Republic—The Lost Suns 1 (First appearance)
- The Old Republic—The Lost Suns 2
- The Old Republic—The Lost Suns 3 (Mentioned only)
- The Old Republic—The Lost Suns 4
- The Old Republic—The Lost Suns 5
- The Old Republic: Annihilation (Mentioned only)
- Star Wars: The Old Republic: Galactic Starfighter (Mentioned only)