Jedi Master Ooroo was a brain-like creature from an ocean world with a cyanogen-rich atmosphere, and was in service during the time of the Great Hyperspace War. While off his homeworld, Ooroo was encased in a yellow crystal that maintained his cyanogen atmosphere, which was mounted on a maneuvering platform. Ooroo was the teacher of one of the most famous philosopher of the Jedi Knights, Odan-Urr. Ooroo often chided Odan-Urr for spending so much time studying books and old historical records, and not taking action when it was appropriate.
However, there came a time when Ooroo felt action was unavoidable, and decided to send his student to the Koros System to be an advisor to Empress Teta herself, and help unite the seventh, and last world to be reclaimed in the Unification Wars. After all Empress Teta's planets had been united, Ooroo learned of his student's dark visions about the threat of the Dark Lords of the Sith empire. Ooroo believed Odan-Urr was correct in the interpretation of his vision, and traveled to Cinnagar to join Odan-Urr. There, Ooroo remained alongside Empress Teta as she built up her fleet and defenses. As Empress Teta prepared for war, the commander of the rebels she fought against in the Unification Wars came to her, wishing to join her military and fight against the Sith.
With the rebel army added, Ooroo travled with Odan-Urr to Kirrek, where the majority of the rebel army resided. Even encased in his tank, Ooroo decided to join the fight in defense of Kirrek, and the Republic. Soon, the Sith forces arrived and the Battle of Kirrek began. As the battle proceeded, the Sith army proved to be a formidable foe, breaking through the ranks of Kirrek soldiers. Even with the help of the Force, the Sith army pressed on, and soon the tide was turning in favor of the Sith forces. Realizing what he must do, Ooroo told his student and the Kirrek soldiers to get back and find shelter.