After New Republic Intelligence Service agent Jan Ors was presumed killed during a mission on Artus Prime, Kyle Katarn, seeking vengeance, went to the Valley of the Jedi in order to re-establish his connection with the Force. Unbeknownst to him, his ship was being followed by Desann and Tavion Axmis. After being led to the Valley, Desann and Tavion used its latent Force energy to empower several soldiers with Force energies. These unnaturally powerful beings came to be known as Reborn Jedi and shadowtroopers. The Reborn combined their forces with those of Imperial warlord Admiral Galak Fyyar, and in doing so, gained enough strength to invade Yavin 4.
With such a force primed for the attack, Fyyar launched the Doomgiver from his base on Cairn Installation. However, Kyle Katarn had infiltrated the Cairn base and was soon on the Doomgiver itself.
The ship launched, with Kyle Katarn in it, and headed for the Yavin system. On board, Katarn eventually managed to alert Rogue Squadron of the Doomgiver, and soon made his way to the detention levels of the ship. After rescuing a still living Jan Ors and learning of the attack on Yavin 4, Katarn set out to disable the shields. In the shield generator room, Katarn met and battled Galak Fyyar, who was operating a mechanical suit made from cortosis. The duel resulted in Fyyar's cortosis suit exploding. After killing Fyyar and disabling the Doomgivers shields, Katarn and Ors were able to reach an escape pod and evacuate the doomed ship. With the shields down, Rogue Squadron was easily able to destroy the Doomgiver.
Despite the destruction of the Doomgiver, several of the ship's All Terrain Rapid Deployment Pods were able to launch before the attack even began, and the ground portion of the battle began in the swamps of Yavin. Joining the ground troops was Kyle Katarn, who made his way through the swamps and to the main temple of the Praxeum.
Desann duels Kyle Katarn.
The ground force of AT-STs, stormtroopers and specially trained swamptroopers along with a few shadowtroopers encountered heavy resistance in the form of New Republic infantry. In the temple, the Rebon forces managed to reactivate the temple's supply of training remotes to open fire on the Jedi.
Upon reaching the Praxeum, Katarn found the Jedi Trainers and trainees to be holding their own against the invading stormtroopers and Dark Jedi. It was, however, clearly apparent that Desann himself was commanding the landing force and was in the Praxeum. Katarn followed traces of the Chistori Dark Jedi throughout the Praxeum, until eventually finding him in the tunnels beneath the ancient temple. The two confronted each other and engaged in a lightsaber duel. Kyle Katarn killed Desann in the duel. Meanwhile, during the duel, New Republic infantry and the Jedi managed to rout the remaining stormtroopers and Reborn. The battle clearly lost, the surviving Reborn forces surrendered.
Fyyar and Desann's attack on the fledgling Jedi Praxeum was one of the first real military tests that the New Jedi Order had to face. Despite the victory, Desann's apprentice Tavion Axmis still survived as well did several Reborn. They would later attempt to resurrect the spirit of Sith Lord Marka Ragnos. The events of the attack on the Jedi Praxeum also led Kyle Katarn to return to the New Jedi Order.
The mission appears in the 2002 video game Star Wars: Jedi Knight II: Jedi Outcast.