Darth Zannah was a Dark Lord of the Sith and the Sith apprentice of Darth Bane. Zannah was trained to carry Bane's teachings and the Rule of Two forward after a war between the Sith and Jedi Orders.
Sidious broke the Rule of Two at least twice: once by training Darth Maul while still under the tutelage of Darth Plagueis; and secondly, by taking on two apprentices at once, and in the form of two Jedi: Count Dooku, the former Padawan of the legendary Jedi Master Yoda, dubbed Darth Tyranus, and the Fosh Jedi Vergere.
Cognus ascended to Sith Mastery years later, taking the three-eyed Human mutant Darth Millennial as her apprentice.
Nihilus had one apprentice during his lifetime, Visas Marr, who betrayed him preceding his death in 3,951 BBY over Telos IV.
Zannah won – Bane tried to possess her and failed. But he wasn't *completely* destroyed…
As part of the Rule of Two, Bane took on an apprentice, Darth Zannah, to whom he passed on his teachings. Zannah escaped the notice of the Jedi Order.
Darth Zannah was a human female, who was Darth Bane's apprentice. She had a natural gift for Sith magic. How powerful was Darth Bane? Extremely powerful for his time, and one of the best ever (not Palpatine level, or even close, but still).
Galen Marek, codenamed Starkiller, was the son of a Jedi fugitive killed by Vader during the Great Jedi Purge. After his father's death, he was trained by Vader since childhood to become the Sith Lord's secret apprentice.
The Rule of Two created a powerful dynamic by limiting the Sith to only one master and one apprentice at a time, although not all Sith followed the rule as some took apprentices of their own while still serving a master.
Talon was written as the aged Maul's apprentice, with Lucas later saying "She was the new Darth Vader, and most of the action was with her." Early story treatments had her corrupting the son of Han Solo and Leia Organa, but her character later evolved into a "Jedi Killer" that ultimately became the character of Kylo ...
Ahsoka Tano, a Togruta female, was the Padawan learner to Anakin Skywalker and a hero of the Clone Wars.
Under the tutelage of Darth Ruyn, Talon's abilities as a force-sensitive were harnessed and she turned into a powerful Sith assassin. Psychologically, she was molded to be completely susceptible to the tenets of the One Sith.
He fell under the influence of Supreme Chancellor Palpatine of Naboo, and left the Jedi Order. After learning that Palpatine was secretly the Sith Lord Darth Sidious, Dooku turned to the dark side and became a Dark Lord of the Sith himself, replacing Darth Maul as Sidious's second apprentice.
Darth Maul was the first Sith apprentice of Darth Sidious. Sometime before the Invasion of Naboo, the Sith Lord Darth Sidious was trained by Darth Plagueis.
The Sith remained hidden for a millennium, allowing the Jedi to believe that their ancient nemesis had gone extinct. The Sith stayed in hiding for a thousand years, their survival unknown to the Jedi, as they continued their revenge against the Jedi through Bane's Grand Plan.
Darth Sidious was the secret persona of Sheev Palpatine and the Sith apprentice of Darth Plagueis. The time period of when Plagueis came to possess his Sith apprentice was unknown, but the Dark Lord chose Sheev Palpatine, a human from Naboo, as his apprentice.
As the first Dark Lord of the Sith, Ajunta Pall founded the first Sith Empire and expanded it onto other worlds. The Sith took over the planet Ziost and created it as their capital and as Pall's new home. Pall eventually died after serving the Empire for many decades, but his Empire lived on.
In 2017, Marvel released Star Wars: Darth Maul, a 5-issue prequel series centered on Maul before the events of The Phantom Menace. The comic details upon Maul's training under Darth Sidious, and how he was manipulated into hating the Jedi for leading the Sith to near-extinction.
Darth Sidious, publicly known as Sheev Palpatine from Naboo, became the Dark Lord of The Sith after betraying and murdering his Sith Master Darth Plagueis. Sidious was the Dark Lord of the Sith during the last years of the Republic and the rise of the Galactic Empire.
The child who would be remembered as Revan was eventually discovered to be Force-sensitive and was accepted into the Jedi Order. The Jedi Master Kreia claimed to have been his first teacher in the ways of the Force.
Darth Nihilus (pronounced /ˈnaɪ. e. lɨs/) was a Human male who reigned as a Dark Lord of the Sith during the era of strife following the Jedi Civil War. Before becoming a Sith Lord, he lost everything during the Galactic Republic's war against the Mandalorian Neo-Crusaders.
Marr was collected from the surface and Nihilus began to train her as his Shadow Hand. One year later, Nihilus sensed a growing presence in the Force and sent Marr out to eliminate it.