Although it's not fully clear where the Darth moniker originated, Darth Andeddu is thought to be the first character to use the title in-universe. Having originated in Legends, Andeddu was mentioned in the new canon in the comic Star Wars Adventures: Return to Vader's Castle 2, which referenced "Andeddu's flames".
The strongest among the Exiles, Ajunta Pall, became the first to hold the title Dark Lord of the Sith. His contemporaries, such as Karness Muur and XoXaan, became Sith Lords. The human Dark Jedi interbred with the Sith species, who also had an affinity for the Dark Side. They would become the original Sith Empire.
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.
Six famous Sith Lords bearing the Darth title, from left to right: Darth Andeddu, Darth Revan, Darth Malak, Darth Malgus, Darth Ruin, Darth Bane. Many Sith Lords chose to add "Darth" to their name, so much so that the word is considered synonymous with the dark side of the Force in some circles.
The most recent Sith Lord before Palpatine was Palpatine's master, Darth Plagueis. In the old Star Wars Legends continuity (no longer canon, alas), Plagueis was notable for his scientific approach to the Force that gave him a control over life and death virtually unprecedented among Force-Users.
History. A dark side warrior with a mysterious past, Kylo Ren was neither Jedi nor Sith, but a product of both sides' teachings. Once an apprentice of Luke Skywalker's, he killed his fellow students and drove Skywalker into exile, becoming a First Order warlord and servant of Supreme Leader Snoke.
Summary. Jar Jar Binks's clumsiness may not be genuine, but rather an act to disguise his true nature as a Sith Lord infiltrating the Republic. Palpatine carefully orchestrated events to manipulate the galaxy, and Jar Jar's involvement suggests he may have been the eyes and ears on Naboo.
Legend had it that Yoda—a Jedi who became Grand Master—was trained by N'Kata Del Gormo. A Force-sensitive Hysalrian, N'Kata Del Gormo was trained in the ways of the Force and achieved the rank of Master within the Jedi Order.
Even though Kylo Ren uses a red lightsaber, harnesses the dark side of the Force, and wears a cape, he is not a Sith. Because of that, he can never hold the title of Darth. Instead, he was just a chaotic mess of the dark side (until he eventually found his way back to the light).
As well as being a gifted bladesman Sidious' connection to the Dark Side is extremely powerful, granting Sidious the ability to conduct force lightning. Likewise, Sidious took on both Darth Maul and Darth Vader as his apprentice, two of the most powerful Sith and best villains in all of Star Wars.
By the end of The Rise of Skywalker, Emperor Palpatine (aka Darth Sidious) is believed to be the last of the Sith Lords. But was he really the last to ever live, or were there others in hiding? According to the current canon, he is indeed the last Sith, but that doesn't appear to be the case in Legends.
The Prime Jedi was an individual who became the first Jedi to ever use the Force. The Prime Jedi was also the founder of the Jedi Order, which they established on the planet Ahch-To around 25,025 BBY.
But he wasn't the man with the plan. Without the Emperor's manipulation, Vader never would have risen from the pits of Mustafar™ to be Dark Lord of the Sith™. For that reason alone, Darth Sidious takes the top spot.
A Sith Lord with the ability to cheat death and create life, Plagueis is the enigmatic mentor of Sheev Palpatine / Darth Sidious, who, in accordance to the Sith's Rule of Two, eventually betrays Plagueis by murdering him in his sleep, taking his place as Sith Master.
The obvious answer is Darth Vectivus, a Sith Lord who lived in his house and didn't try to conquer the galaxy or destroy the Jedi. And while he wasn't evil, he wasn't good, either. However, there is one good Sith. That would most likely be Darth Vectivus.
While Darth Sidious mastered the Dark Side and ruled over an Empire for two decades, Vitiate (or Valkorion) went even further, rebuilding the Sith Empire and ruling over it for a hundred years while he embodied the Dark Side to be perhaps the most powerful and evil being in the galaxy's history.
In his story, Maul poses as a member of a criminal cartel to kill a Force-sensitive thief for Darth Sidious, and experiences a vision of an alternate life as a peace-keeping Jedi, which he denies, much to Sidious' content. The story takes place shortly before The Phantom Menace.
Yoda held the title of Grand Master of the Jedi Order since the days of the High Republic Era. At some point, Yoda took on a human named Kantam Sy as his Padawan. The two were stationed at the Jedi Temple on the planet Endovar.
Like all in the Order, the young Korun boy was taught by Grand Master Yoda when he was a learner, and eventually went on to become a Padawan to another Jedi. At one point during his apprenticeship, Windu trained under Master T'ra Saa.
Darth Gonk (Later Darth Wrife) was a force sensitive droid. He reigned during the first years of the Galactic Empire to the years of the Fel empire. He had a vast knowledge of the force that even rivaled the most powerful sith, such as Darth Sion and Darth Maul.
Summary. Anakin Skywalker's birth mystery is solved - his mother, Shmi Skywalker, reveals that there was no father and she can't explain what happened. Qui-Gon Jinn believed that the Force itself created Anakin in Shmi's womb, making him the Chosen One who would bring balance to the Force.
Of course, Star Wars: The Last Jedi put an end to that theory when Kylo Ren betrayed and killed his master, while Star Wars: The Rise of Skywalker revealed that Snoke was created by Palpatine. Supreme Leader Snoke was indeed a new character and most certainly didn't have any ties to Jar Jar Binks.
