Darth Vitiate / Sith Emperor from Most Powerful Sith Lords of All Time

Vitiate, known for the vast majority of his life as simply the Sith Emperor and known to his Eternal Empire as Valkorion, was a Dark Lord of the Sith who reconstituted the Sith Empire after its destruction in the Great Hyperspace War and went on to rule it for over 1300 years. To the people of the Eternal Empire over which he ruled in his later life, he was His Glorious Majesty, Slayer of Izax, Immortal Master and Protector of Zakuul—their Immortal Emperor. Born in 5113 BBY as Tenebrae, the illegitimate Sith son of Lord Dramath of Medriaas and a poor farm woman, the child who eventually became the Emperor killed his own father at the age of ten and was granted the title of Lord Vitiate by the then–Dark Lord Marka Ragnos three years later. Vitiate renamed his world Nathema and ruled it for the next century, content to exclude himself from Sith power struggles and even the Great Hyperspace War when the Galactic Republic destroyed the Empire in 5000 BBY. Summoning the remaining Sith Lords to Nathema with the promise of salvation from the Jedi, Vitiate turned on his fellows and used their strength to perform a ritual that made him immortal, at the expense of every living thing on Nathema.