Immortality

Immortality is the state of a biological being living indefinitely for a seemingly infinite or indeterminant amount of time. This state was the goal of many Sith Lords throughout history, and at least one Jedi; though the former was more interested due to the Sith's tendencies to fear death and the unknown, and the ultimate Sith goals of power, control and glorification of self.

History
The Lord Emperor believed himself to be the first Sith Lord to even to come close to true immortality.