In the opening year (first year) of the expansive conflict known as the Great Galactic War, the forces of the Galactic Republic launched an aggressive military campaign targeting the Tingel Arm, an area under the growing influence of the resurgent Sith Empire. This campaign was triggered by the Empire's re-emergence into the known galaxy after an extended exile lasting centuries within the uncharted Unknown Regions. Following their successful invasion and capture of the Republic's strategically important Aparo sector, the Sith Empire consolidated its power in the Tingel Arm, where a significant portion of the population had already shifted allegiance to the Sith. Unaware of this widespread defection, the Republic dispatched its Navy with the intention of reclaiming this vital region of space. The Republic's hopes of leveraging existing alliances with the inhabitants of Belkadan, Sernpidal, and Ruuria within the Tingel Arm were quickly dashed, as their forces found themselves embroiled in a desperate battle for survival against worlds already firmly under Imperial control. Despite reinforcements of ships arriving from across the Navy, the Republic's fleet faced overwhelming odds when the Imperial Navy intervened to bolster the Empire's puppet regimes in the Tingel Arm. With their control over Belkadan, Sernpidal, and Ruuria secured, the Sith were then able to redeploy their naval assets towards Korriban, their ancestral homeworld and the true primary objective of their initial military operations. Consequently, the Republic was forced to withdraw its forces from the Tingel Arm, suffering yet another defeat at the hands of the Imperial Military's rapid offensive.
Subsequent to the events of the Great Hyperspace War, the remnants of the ancient Sith Empire retreated from the known galaxy, dedicating themselves to rebuilding and transforming into a new empire within the relative isolation of the Unknown Regions. During this extended time of rebuilding, the Sith Emperor meticulously formulated and prepared for a large-scale invasion of Galactic Republic controlled space. The Empire secretly forged alliances with several Republic-aligned worlds situated in the Tingel Arm, installing compliant puppet governments on these planets to ensure their unwavering loyalty. In the year 3681 BBY, the Imperial Navy revealed its presence on the fringes of the Tingel Arm, drawing Republic observers into a trap before destroying them in the initial skirmish that would eventually escalate into the larger Great Galactic War.
In the immediate aftermath of these opening engagements, the Republic was slow to mobilize its forces in order to effectively defend the various worlds within the Outer Rim Territories. As a direct consequence of this delayed response, the Aparo sector fell under the control of the Sith even before the Republic Navy could fully deploy its assets to the region. Finally, reacting to the Imperial Military's sudden and devastating attacks, the Republic rallied its naval forces and launched a direct counter-offensive into the Tingel Arm, remaining largely unaware that many of the worlds within the region had already capitulated to the Empire and entered into alliances with the Sith.
The Republic fleet made its entry into the Tingel Arm along a trajectory originating from an outer spiral arm of the galaxy. The fleet strategically positioned itself between the planets of Belkadan and Sernpidal, located within the Dalonbian sector, as well as Ruuria in the adjacent Xappyh sector. However, unbeknownst to the Republic's military command, these specific planets were among those that had already switched their allegiance to the Sith Empire and were now operating firmly under Imperial directives. Finding itself caught between the combined military strength of the puppet governments established by the Imperials, the Republic fleet was quickly forced into a defensive posture.
In response to this unexpected disadvantageous situation, Republic leadership issued an urgent call for all available vessels to provide immediate reinforcement to the beleaguered fleet operating within the Tingel Arm. Despite the influx of additional Republic firepower and personnel, the Sith forces still managed to overwhelm the Republic fleet once the Imperial Navy committed its own powerful forces to support the Imperial-aligned governments within the Tingel Arm. In order to prevent complete annihilation, the Republic fleet executed a series of evasive maneuvers around Sernpidal and initiated a full-scale retreat from the region. The majority of the fleeing fleet eventually found safe harbor at the planet Mirial, located within the Illisurevimurasi sector.
The disorganized retreat of the Republic fleet served as a clear indication that the ongoing war would not be a balanced or easily won conflict. Following the unsuccessful campaign within the Tingel Arm, the Republic's top military commanders were unable to reach a consensus regarding the optimal location for the dispersed fleet to regroup and reorganize, which ultimately led to further strategic losses within the region. As a direct consequence of the Republic vessels being diverted from their assigned posts to participate in the Tingel Arm campaign, numerous strategically important regions throughout the galaxy were left dangerously undefended. One such vulnerable location was the ancient Sith homeworld of Korriban, which was left under the protection of only a small contingent of Jedi security ships. The Empire, having successfully secured a reliable hyperspace route to Korriban through the capture of Belkadan, Ruuria, and Sernpidal, dispatched a large fleet of powerful warships to the planet and successfully retook it during the ongoing conflict within the Tingel Arm, all without the Jedi High Council even being fully aware that they had lost control of it. These events, coupled with the loss of the Aparo sector and several other key worlds in the Outer Rim, triggered widespread panic on the Republic's capital world of Coruscant. The Galactic Senate and Jedi Council convened in an emergency session to formulate a comprehensive plan for the defense of the galaxy, but the proceedings quickly became bogged down in partisan politics, with numerous senators openly refusing to participate after their respective homeworlds were allocated little to no protection by the Republic's armed forces.
The disarray within the Republic's government and the increasing power of the Empire in the Outer Rim provided the Sith Emperor with the opportunity to prepare his forces for a protracted campaign aimed at conquering the Galactic Core. The Republic remained on the defensive for the subsequent decade, until a historic stand was made at Bothawui in 3671 BBY. The Kel Dor Jedi Master Gnost-Dural meticulously documented his experiences during these early days of the war in a personal journal, which included detailed accounts of his deep concern regarding the Republic's defeat in the Tingel Arm. This volume later became the inaugural entry into the newly established Jedi Archives on Tython. Following the conclusion of the war with the signing of the Alderaan peace conference, Gnost-Dural created a new, more scholarly holorecord detailing the events surrounding the outbreak of the Great Galactic War, and once again included comprehensive information regarding the Tingel Arm campaign.
The Tingel Arm campaign was initially presented in Onslaught of the Sith Empire, which was the sixth installment of the Galactic Timeline series. The Galactic Timeline is a collection of online videos presented as historical narratives that explore the backstory of LucasArts' and BioWare's massively multiplayer online role-playing game, Star Wars: The Old Republic. These installments are available for viewing on the game's official site and are narrated by the Kel Dor Jedi Master Gnost-Dural, whose voice is provided by actor Lance Henriksen. The campaign was subsequently referenced in The Journal of Master Gnost-Dural, an in-universe account of the Great Galactic War that was included with the collector's edition of The Old Republic.
- Timeline 6: Onslaught of the Sith Empire on The Old Republic's official website (article) (backup link) (First mentioned)
- The Journal of Master Gnost-Dural
- Book of Sith: Secrets from the Dark Side
- Star Wars: The Old Republic Encyclopedia (Indirect mention only)