The Mysterious Sith Emperor

"When the Emperor planned on the Republic's destruction, he did not foresee the need for alliances. The Sith would sweep across the galaxy, systematically exterminating their age old Jedi enemies and dismantling the proud Republic." Jedi Master Gnost-Dural inside the holocron on the Great Galactic War.

The Emperor survived the ancient Sith Empire's defeat during the Great Hyperspace War, and fled to Dromund Kaas with his most trusted Sith Lords. There, he began building a new, revitalized Empire, vowing to return and overcome the Republic. Using dim rituals, the Sith Emperor extended his life and his undeniable law.

After the Mandalorian Wars. The well known Jedi Knights Revan and Malak journey into the unknown regions in explore of the Star Forge which guide them into make contact with with the Sith Emperor. He evidently dishonored them and gave them a assignment to come back to the Galactic Republic and serve up as a advance guard for a Sith invasion thus start the Jedi Civil War.

Through out the Jedi Civil War, Darth Revan purposely absent key Republic infrastructure intact on numerous planets to assure firmness so that he could take his Empire to war with the concealed section lead by this mysterious Emperor. Revan's vital plan never came into fruition as Malak betrayed him and took the mantel of Dark Lord of the Sith for himself, compassionate little for his former master's aspirations of stability Malak sought to annihilate anything that got in his way to achieve his goals.

Malak was in the end hunted down and killed by his previous master, who was redeemed by the Jedi Council, in effect putting an end to the potential vanguard. After Darth Malak's decease, the remains of Revan's Empire was ruined by the Jedi Exile who shortly after her victory departed to the Unknown Regions to join Revan, who left at the end of the Jedi Civil War, on his quest against the Emperor.

About 300 years later it was supposed that they were unsuccessful when the "True" Sith lastly returned and in progress the Great Galactic War and they were not at all seen another time.