Sorzus Syn was a female Jedi who was exiled from the Jedi Order following the Hundred-Year Darkness. Sorzus Syn and her fellow Dark Jedi enslaved the native Sith of Korriban, christened themselves the first of the Sith Lords, and instituted a new order that centered around worship and practice of the dark side of the Force.
During her reign, Syn wrote a journal that was later included in the Book of Sith, which was a chronicle of her encounters with Sith Purebloods, explorations in alchemy, and the foundations of the Sith Order. She was apparently the original author of the Sith Code.