The Devastation of Manaan represents an action undertaken by the Sith Empire during the Great Galactic War, targeting the planet of Manaan. This event transpired sometime between the dates of 3681 BBY and 3653 BBY. Following centuries spent concealed within sectors of space uncharted by the Galactic Republic, the Sith resurfaced in the known galaxy, commencing their war against the Republic's affiliated worlds and other planets. As part of their quest for supremacy, the Empire journeyed to Manaan, a water-dominated world celebrated for its steadfast commitment to neutrality amidst times of conflict. Disregarding the Selkath's established tradition of impartiality, the Sith initiated an orbital bombardment, which resulted in the destruction of nearly all of Manaan's surface structures. Consequently, the Selkath species entered a prolonged period of isolation from galactic affairs. It took numerous years for them to reestablish connections with the wider galactic community, and they remained suspicious of both the Republic and the Sith Empire.
After a self-imposed exile lasting several centuries in the distant Outer Rim Territories, the Sith revealed their presence and their rebuilt Empire to an unsuspecting galaxy in 3681 BBY, thus igniting the Great Galactic War. In this war between the Sith and the Galactic Republic, the Imperials secured significant victories while the Republic suffered from political discord and economic decline.
The Empire also clashed with fiercely independent societies during the war, including the Selkath inhabiting Manaan. Manaan, a planet largely covered in water, had a long history of neutrality during galactic conflicts. Notably, during the Jedi Civil War of the Old Sith Wars era, the native Selkath successfully maintained their impartiality and supplied their kolto healing compound to both the Republic and Darth Malak's Sith Empire. Seeking exclusive access to kolto, the Empire demanded Manaan's allegiance. The Selkath responded by offering neutrality, similar to their stance during the Jedi Civil War. However, this offer only provoked the Empire's anger.
As a consequence of the Selkath's neutrality proposal, the Empire initiated an orbital bombardment of Manaan from space. This assault led to the destruction of almost every surface structure, including their capital city, Ahto City. During this attack, Vinyor Tesh's mother and father, both researchers stationed on the planet, were killed. A Jedi named Laotah, who was visiting Manaan at the time, rescued the young orphan and brought him to Coruscant for training at the Jedi Temple. Unable to provide assistance due to their own war efforts, the Republic left the Selkath feeling betrayed. Consequently, the Selkath conducted a mass retreat into the oceans of Manaan, abandoning their floating cities to ruin.
The Sith attack, which was subsequently recognized by historians as "the Devastation of Manaan", and the Republic's failure to provide aid, fostered resentment towards outsiders among the Selkath. They began to view all foreigners, regardless of their affiliation with the Empire or the Republic, as slavers and enemies. The Selkath spent many years isolated from the galaxy, during which time the Force-sensitive Order of Shasa rose to prominence as protectors of the Selkath. Selkath culture flourished in isolation, but some individuals began to recognize the economic advantages of engaging in trade with off-worlders. Mahreen, a Mon Calamari diplomat, invested several years in persuading a delegation from the Order of Shasa to meet with her. The Selkath also recognized their declining economy and began to discuss the issue amongst themselves.
Upon finally deciding to end their isolation, Mahreen convinced the Selkath to transform one of the few remaining surface structures into the Mercantile Plaza, a trading hub with strict regulations regarding landing privileges. Initially, only ambassadors from the Republic were permitted, but the Selkath politician Shuuru eventually extended an invitation to the Sith Empire, driven by his distrust of the Republic's inaction during Manaan's crisis. Ahto City remained in ruins for decades, and the Selkath established the Manaan Special Warfare Group as a nascent defense force for their planet, although the Sith Empire's intelligence agencies deemed the organization inadequate to repel an invasion. Around 3626 BBY, the Sith Empire began to mobilize their forces for an invasion of the planet as part of their ongoing renewed war with the Republic. The Empire's Dark Council considered this action to be retribution for the planet's refusal to adequately share their kolto reserves.
The devastation of Manaan was initially referenced on the official website for the LucasArts video game, Star Wars: The Old Republic. This information was available on "The Setting," a webpage designed to provide context for the game's historical setting. Since its creation in 2008, The Old Republic's website has undergone numerous revisions, leading to the removal of some of the original content. "The Setting" was updated in mid-2011, and the information about Manaan was removed. It was later elaborated upon in promotional material for Game Update 2.9 of The Old Republic, which introduced a Flashpoint set on Manaan, and in entries within the in-game Codex that discussed Manaan. An in-universe intelligence report, published on the game's official website on July 30, 2021 as part of the lead-up to the Legacy of the Sith expansion, canonized the event's name.