in the ("legends") continuity, the sith order began around 6,900 bby, during a period known as the hundred year darkness. a series of conflict began between the rebellious dark jedi, a faction of the jedi order, and the rest of the order. the dark jedi were defeated and cast out, exiled to the unknown regions. these exiles came across the planet korriban, and its native species, the sith. 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.