The Most Powerful Sith Lord Of All Time
Darth Sidious was widely considered to be the most powerful Sith. He was able to defeat Master Yoda in combat, manipulate the Jedi Council, help create Darth Vader, and become the Supreme Emperor of the galaxy. He probably is the strongest Sith in canon. However, in Legends, there is another Sith of legendary skill, ability, and evil. He might even rival, if not surpass, Darth Sidious. His birth name is Tenebrae. Although though he has quite a few titles and names under his belt, his most infamous name was Darth Vitiate.
Tenebrae was born 5113 BBY (Before Battle of Yavin) to a Sith Lord named Dramath on the planet Medriaas. At the age of 6, he slaughtered his entire village and then, at the age of 10, led a path of destruction across the planet, killing thousands along the way. When his father confronted him about the massacre, Tenebrae severed his father from the Force, and imprisoned his spirit. After committing mass genocide, Tenebrae ventured to Ziost and met with Marka Ragnos, the Dark Lord of the Sith. Ragnos was so impressed with Tenebrae that he made Tenebrae a Sith Lord basically on the spot, awarding him the name Darth Vitiate. That was only the beginning of his rise to power.
After taking on the mantle of Darth Vitiate, he decided to stay out of the power struggle currently going on between two of the high-ranking Sith Lords. However, when one of them was defeated in the Great Hyperspace War, Vitiate saw an opportunity to seize control of the Sith. He summoned 8,000 Siths who survived the war to Nathema, and used Dark Side sorcery to dominate the will of every Sith there. He then used their power to absorb and destroy all living things on the planet except for his own! This not only granted him immense power, but also immortality. From then on, he would lead the scattered Sith survivors to Dromund Kaas, where he would rule as Sith Emperor.
Vitiate was second to none in terms of sheer power, if that had not already been clear. At an extremely young age, he was able to snap his step-father’s neck with just a thought and used the Force to torture his mother for months. As he grew, he became a student of Sith history and dark arts, and became extremely proficient in Sith magic and alchemy. One of his most deadly abilities was the ability to use the Force to dominate the minds of others and bend them to his will. He could also use the Force to feed on the spirit of the dying to heal himself and extend his lifespan. When the Dark Side took a toll on his physical appearance, he could transfer his consciousness into a new body with the Force. This was essentially what Darth Sidious had been trying to do in canon. Vitiate had already accomplished this thousands of years before Sidious was born. Naturally, he had an enormous repertoire of telekinetic abilities that would put most other Jedi and Sith to shame. He could even use the Force to transfer part of himself into other beings, basically creating the greatest sleeper agents. In addition, he was proficient in lightsaber combat, although he rarely needed to use it.
Vitiate would go on to try to recreate the ritual which made him immortal on a galactic scale, so he could theoretically become a god. In order to create an enormous amount of chaos and hate for the ritual, he manipulated the Mandalorians into starting a war with the Republic. The Jedi warriors Revan and Malak went to confront him after the Mandalorian War, but he bent their wills to him and turned them to the Dark Side. He then sent them back to find the Star Forge and start the Jedi Civil War. Revan would break free of his control and confront him once again, but Vitiate had turned himself into a being of pure Force energy. He then moved his consciousness through multiple bodies to better protect himself. He would go on to start the Great Galactic War. He was stopped from completing his final ritual by the combined forces of the Jedi Order and the Republic Navy. It only sent him into a deep slumber, however. Centuries later, he would later return as Valkorion, with three powerful offsprings. One of them inevitably turned on him, and finally destroyed both his body and spirit for good.
Obviously, all of this is now part of Legends, and the odds of it becoming canon are incredibly low. However, it is interesting to see a Sith with such power. There may not even be a character in the current Star Wars canon that can match him in a contest of power and Force knowledge. The amount of creativity and thought that went into his character is amazing, and I hope that Lucasfilm will take bits and pieces from his story for future Star Wars stories. There is always the chance he is out there in canon, just resting for when he returns to life once more.