Codex/Galactic History 77: A Return to the Unknown Regions

The Galactic History 77: A Return to the Unknown Regions codex entry is located within the Achievements:Datacrons section of a player's codex once it has been unlocked.

Codex entry
"This datacron holds unheard of power and knowledge collected by an ancient race. You access its power and discover writings which are clearly only one small piece of a massive galactic history:

With Darth Malak gone and the Star Forge destroyed, peace returned to the galaxy. The Republic and the Jedi began regaining strength after the Jedi Civil War.

But for the redeemed Jedi Revan, peace was fleeting. Old memories began to surface–fragmented memories of the lost Sith Empire building strength on Dromund Kaas. Revan knew that the Sith would not remain in the Unknown Regions forever, and that the Republic was not strong enough to face them.

Finally, Revan made a decision. After leaving behind instructions with allies like Bastila Shan and Carth Onasi, Revan left for the Unknown Regions hoping to put an end to the Sith Empire. He was never seen again."