- "He's still exploring down there, in those depths. He's going deeper, and finding more, and one day he'll emerge with news that will astound us all."
- ―Osamael Or's sister about him
Osamael Or was a frontiersman before the rise of the Galactic Republic who explored the planet Tython, around 35,453 BBY. During his explorations through an unknown region in the continent of Talss, he journeyed to the Old City, and wrote in his diary about what he discovered about the Gree.
He never returned from the city, but his diary came into the possession of Lanoree Brock nine thousand years later. Within the diary there was mention of the Gree and their technology, such as a device that was powered by dark matter, which was translated as 'step to the stars'. After Brock read it, she thought that there must have been more written within other diaries, as it was incomplete.
- Dawn of the Jedi: Into the Void (First mentioned)