The conflict that occurred circa 21 BBY on the Sedawan involved the forces of the Galactic Republic against the Nightsisters.
The Republic transport vessel, Sedawan, while transporting lightsaber crystals originating from Ilum, was ambushed by the warship Devastation. Projectiles deploying Buzz droids struck the cargo ship, allowing the droids to infiltrate it. Simultaneously, the Nightsisters Yansu Grjak and Sai Sircu made their way into the ship's hangar. Jedi Master Luminara Unduli promptly led a unit of clone troopers toward the hangar. The Nightsisters eliminated all of the clones, and Unduli was taken as a prisoner. Upon hearing this news, the Jedi Council made the determination to dispatch two Jedi. Utilizing a Jedi bomber, they landed within the main hangar. They swiftly advanced towards the command bridge, destroying various Buzz droids and Battle Droids along their path. They arrived at the bridge, only to find it deserted. They soon realized that multiple escape pods had been launched recently, yet the destination coordinates had been erased from the system. Yansu then appeared on the bridge and unleashed Force lightning, sending the two Jedi flying backwards. The electrical discharge also damaged the ship's computer systems, causing the bridge to begin to explode. The Jedi quickly retreated, sealing the doors to the bridge to contain the spreading flames. They pressed onward, avoiding falling debris as the ship began to disintegrate, while also eliminating the remaining Buzz droids. They eventually caught up with Yansu in another hangar. She escaped in her Star Courier, leaving behind a group of Nightsisters to engage the Jedi, but these warriors were easily defeated and killed. The Jedi then established communication with the Jedi Council.