The conflict known as the Battle of Yavin 4, alternatively referred to as the Attack on the Jedi Academy, unfolded during the Galactic Civil War in the year 12 ABY. In this engagement, the forces of Luke Skywalker's Jedi Praxeum successfully repelled the invading forces led by Admiral Galak Fyyar and Desann.
Following the presumed death of New Republic Intelligence Service operative Jan Ors during a mission on Artus Prime, Kyle Katarn, driven by a desire for revenge, journeyed to the Valley of the Jedi to reconnect with the Force. Unbeknownst to Katarn, his vessel was being tracked by Desann and Tavion Axmis. Upon arriving at the Valley, Desann and Tavion harnessed its dormant Force energy to imbue several soldiers with Force abilities. These enhanced warriors became known as Reborn Jedi and shadowtroopers. The Reborn then allied with the forces of Imperial warlord Admiral Galak Fyyar, thereby amassing sufficient power to launch an invasion of Yavin 4.
With his forces ready for combat, Fyyar deployed the Doomgiver from his base situated at the Cairn Installation. However, Kyle Katarn had already infiltrated the Cairn base and subsequently boarded the Doomgiver itself.
The vessel departed, carrying Kyle Katarn, and proceeded towards the Yavin system. While onboard, Katarn eventually managed to alert Rogue Squadron to the presence of the Doomgiver, and subsequently made his way to the ship's detention area. Following the rescue of a still-alive Jan Ors and learning of the impending assault on Yavin 4, Katarn embarked on a mission to disable the ship's shields. Within the shield generator room, Katarn confronted and battled Galak Fyyar, who was piloting a mechanical suit constructed from cortosis. The confrontation culminated in the destruction of Fyyar's cortosis suit. After eliminating Fyyar and deactivating the Doomgiver's shields, Katarn and Ors managed to reach an escape pod and abandon the doomed vessel. With the shields down, Rogue Squadron was then able to easily destroy the Doomgiver.
Despite the destruction of the Doomgiver, several of the ship's All Terrain Rapid Deployment Pods had been launched before the attack even began, and the ground portion of the battle commenced in the swamps of Yavin. Kyle Katarn joined the ground forces, navigating through the swamps towards the main temple of the Praxeum.
The ground forces, consisting of AT-STs, stormtroopers, and specially trained swamptroopers along with a few shadowtroopers, encountered fierce resistance from New Republic infantry. Within the temple, the Reborn forces managed to reactivate the temple's supply of training remotes to open fire on the Jedi.
Upon reaching the Praxeum, Katarn discovered that the Jedi Trainers and trainees were successfully holding their ground against the invading stormtroopers and Dark Jedi. However, it was evident that Desann himself was commanding the landing force and was present within the Praxeum. Katarn tracked the Chistori Dark Jedi throughout the Praxeum, eventually locating him in the tunnels beneath the ancient temple. The two engaged in a lightsaber duel, which resulted in Kyle Katarn killing Desann. Simultaneously, New Republic infantry and the Jedi managed to defeat the remaining stormtroopers and Reborn. With the battle clearly lost, the surviving Reborn forces surrendered.
The attack on the fledgling Jedi Praxeum by Fyyar and Desann represented one of the initial significant military challenges faced by the New Jedi Order. Despite the victory, Desann's apprentice Tavion Axmis and several Reborn survived. They would later attempt to resurrect the spirit of Sith Lord Marka Ragnos. Furthermore, the events surrounding the attack on the Jedi Praxeum ultimately led Kyle Katarn to rejoin the New Jedi Order.
This particular mission is featured in the 2002 video game Star Wars: Jedi Knight II: Jedi Outcast.