Revan Reborn vs Dark Empire Luke Skywalker

Now, he sought out the only other Sith practitioner who could challenge him -- Ulic Qel Droma.

--Ulic Qel-Droma, Star Wars Databank

Meanwhile on Yavin 4, a more powerful EXAR KUN rests in his meditation chamber, reaching out across the galaxy and detecting other Sith practitioners with his psychic tendrils. Believing himself to be the instigator of a new Sith Golden Age, Kun journeys to the Empress Teta system to destroy Ulic, knowing him to be a threat to his power

--Chronicles of the Old Republic

"Exar Kun. Once the most powerful and dangerous of the Dark Lords of the Sith, he was responsible for the deaths of millions four millennia before the Rise of the Empire."

-- The Complete Star Wars Encyclopedia.

DE Luke>Yoda~ROTS Sidious>>TPM Sheev>>>TPM Maul>Kun>>>Ulic>Vitiate>>>SOR Revan>>Revan Reborn.