In 3756 BBY, Barel Ovair, a Human Jedi Master, and his Nautolan Padawan, Eison Gynt, embarked on an assignment to the fourth moon orbiting the planet Yavin. The pair had spent a considerable amount of time together, journeying to various locations across the galaxy that possessed a strong connection to the Force. Their intention was to explore the Massassi Temples situated on Yavin 4 and delve into the tomb belonging to the ancient Sith Lord Naga Sadow. However, Ovair was secretly a servant of the exiled Sith Empire, tasked with eliminating the spirits of long-dead Sith who could potentially challenge the authority of the Sith Emperor upon his return to known space.
After arriving at the moon, Ovair and Gynt found themselves under attack from Sadow's remaining Massassi warriors. They were defeated and driven into the depths of Sadow's tomb, where they were overwhelmed by the lingering dark energies of the Sith Lord. Ovair failed to complete his mission and abandoned Gynt. Some Weeks later, he made his way back to the Jedi Temple located on the planet Coruscant, reporting that Gynt had perished. But the young Nautolan lived, only to be possessed by Sadow's spirit and killed by Ovair years later.
Following the Sith Empire's defeat at the close of the Great Hyperspace War in 5000 BBY, Naga Sadow, the Dark Lord of the Sith, fled the forces of the Jedi Order and the Galactic Republic, seeking refuge on the fourth moon of the world Yavin, which was located in the Outer Rim. On this moon, Sadow's Massassi servants erected massive temples to honor the Dark Lord, one of which ultimately became his tomb. Meanwhile, other survivors of Sadow's defeated Empire retreated into self-imposed exile in the Unknown Regions, striving to create a new Imperial regime under the leadership of one of the last surviving Dark Lords.
This Dark Lord, known solely as the Sith Emperor, started preparing his Sith for a renewed war against the Republic to avenge their defeat during the Great Hyperspace War. To accomplish this, the Emperor sent spies throughout the galaxy to infiltrate the Republic and weaken it from within. Some of these spies belonged to the Ovair family—Sith who were tasked with posing as Jedi to gain access to the burial sites of dead Sith Lords. The Ovairs' objective was to destroy the spirits of these Sith, preventing them from challenging the Sith Emperor's power when he returned to the known galaxy.
Barel Ovair, a Sith spy of the third generation, continued the work of his father and grandfather under the guise of a Jedi Master and a scholar. Together with his Padawan, the Nautolan Eison Gynt, Ovair traveled the galaxy in search of Sith spirits. Gynt was unaware of his Master's true mission, as Ovair had informed both his apprentice and the Jedi Council that their travels were for the purpose of investigating locations with a strong connection to the Force. The pair embarked on increasingly dangerous missions until 3756 BBY, when the elder Jedi decided to take his apprentice to Yavin 4 to explore the Massassi Temples. However, his real plan was to infiltrate Naga Sadow's ancient crypt and destroy any remaining traces of the Dark Lord's spirit.
Upon their arrival on the moon, the two Jedi headed towards the massive temple that housed the Dark Lord's remains. Before they could enter the structure, they were ambushed by hordes of Massassi warriors emerging from the surrounding jungle. These Massassi had survived the centuries since Sadow's death, remaining to guard their master's tomb. They had been twisted by Sadow's experimentation from many years prior and were now mutated wielders of the dark side of the Force. Ovair and Gynt fought their way into the temple, where they were attacked by even more of the alien guards.
Despite their determined efforts against the Massassi, they were ultimately defeated and forced to retreat into the temple's heart, where Sadow's sarcophagus was located. There, they experienced the overwhelming power of the dark side emanating from the Dark Lord's body. However, Ovair failed to destroy Sadow's spirit and fled the moon, abandoning his apprentice within the tomb.
Some weeks after the mission, Ovair reappeared at the Jedi Temple on Coruscant. The false Jedi Master seemed heavily wounded and partially insane due to the ordeal, and he received intensive care. His recovery process was lengthy, but Ovair was eventually able to report on the incident on Yavin 4. In an address to the Republic's Galactic Senate, Ovair recounted the horrors he had faced on the moon and claimed that Eison Gynt had been killed during their captivity within the tomb. Ovair resumed his duties as a Jedi, but several years later, Gynt reappeared on Coruscant, possessed by Naga Sadow's spirit. He intended to kill Ovair as revenge for his attempt to destroy the Dark Lord's spirit on Yavin 4.
Gynt attacked his former Master, but Ovair triumphed in the subsequent duel, killing the Padawan and neutralizing Sadow's specter, thus fulfilling the command given to him by the Sith Emperor. Approximately a hundred years later, following the Sith's successful campaign against the Republic and the Jedi, Gnost-Dural, a Jedi historian, investigated the events surrounding the mission to Yavin 4. Gnost-Dural's research exposed Ovair's true allegiances and the reasons for his travels, as well as his family's heritage and their contribution to the Empire's war against the Republic. Satele Shan, the Jedi Grand Master of that era, agreed with Gnost-Dural's research and included notes on the mission to Yavin 4 in a wartime journal submitted to the Jedi Archives on Tython.
The Yavin 4 mission first appeared in the seventh installment of the Galactic Timeline, an online video series created to provide background information for the LucasArts/BioWare video game Star Wars: The Old Republic. The installment, titled "Peace for the Republic?," was released on April 16, 2010, on The Old Republic's official website and features actor Lance Henriksen as the voice of Jedi Master Gnost-Dural. "Peace for the Republic?" presents a contradiction regarding the destruction of Naga Sadow's spirit. While the 2008 reference book The Complete Star Wars Encyclopedia had previously stated that the Dark Lord Freedon Nadd destroyed Sadow's spirit in 4400 BBY, the Timeline suggests that Sadow's spirit was still present on Yavin 4 approximately 644 years later.
- Timeline 7: Peace for the Republic? on The Old Republic's official website (article) (backup link) (First mentioned)
- The Journal of Master Gnost-Dural