Onager-class Star Destroyer

The Onager-class Star Destroyer, also known by the moniker Imperial Siege Breaker among members of the Rebel Alliance, was a cruiser-class superweapon measuring 1,288 meters in length. It was built by Rothana Heavy Engineering under contract from Kuat Drive Yards, with a production cost of 376,500,000 credits. According to Rebel Alliance members, the Galactic Empire could have constructed thousands of Onager-class Star Destroyers for the same financial investment as a single "planet-killer."

The Onager-class was powered by a quintet of sublight engines situated at the starship's stern, with three being larger than the remaining pair positioned between them. The engines were strategically located in the most fortified area of the vessel. A solar ionization reactor, identifiable by its distinctive dome shape, was integrated into the ventral hull. The bridge was situated atop a nearly trapezoidal structure, which itself was positioned on an elevated command tower located centrally towards the ship's rear. The Onager-class Star Destroyer incorporated advanced targeting systems and long-range sensor arrays, along with a navigation computer. Its primary hyperdrive was rated class 1.75, supplemented by a class 6 backup.

The ship's fore section was distinguished by dual prongs that formed a hammerhead-like, T-shaped bow. This structure featured a lengthy central indentation that extended nearly to the midship, where the primary armament was housed. Beyond the indentation's termination, but before the command tower structure, were a pair of deflector shield generator domes, similar to those found on Imperial-class Star Destroyers, along with multiple other deflector shield generators. This particular segment of the vessel accommodated the various generators, concentrating their energy to amplify the ship's offensive capabilities. The deflector shields were primarily focused on the ship's front, reflecting its emphasis on forward firepower. Over half of the deflector shields were concentrated towards the front, leaving the aft and sides of the Onager-class more susceptible to attack, especially the engines and flanks. The ship's designers deemed this trade-off acceptable.

Mirroring the design of Imperial-class Star Destroyers, the Onager-class featured a ridge running along the port and starboard sides of the vessel. The Onager-class possessed two hangar bays, one located on the rear of each prong forming the T-shape of the bow. Its standard complement included six Lambda-class T-4a shuttles and thirty-six TIE fighter series starfighters. A crew of 25,200 personnel, including officers, pilots, and enlisted crew, operated the Onager-class, which also had capacity for 240 troops. The vessel carried provisions sufficient for one year of operation.

The primary weaponry of the Onager-class was located within the indentation, consisting of either two shorter-range Superheavy Composite Beam Turbolasers, regarded as specialized battery armaments, or a pair of Orbital Bombardment Particle Cannons, classified as mass-driver cannons. Rebel Alliance members speculated that these weapons were fueled by kyber crystals. The Alliance believed that the power of these crystals was such that they could shatter mountains and overcome all but the most resilient energy shields, thus designating the ship as a superweapon.

These weapons, situated within the vessel's indentation, extended for more than half the ship's length, with their bases positioned at the indentation's beginning near the bridge. Each weapon featured at least three rings spaced along the indentation's length, through which the weapons' payload was discharged. During firing, the indentation and rings glowed red or blue, depending on whether the Orbital Bombardment Particle Cannons or Superheavy Composite Beam Turbolasers were in use, respectively.

The particle cannons were capable of firing in rapid succession, while the beam turbolasers could be discharged simultaneously. These two Superheavy Composite Beam Turbolasers and Orbital Bombardment Particle Cannons were considered among the most devastating weapons possessed by the Galactic Empire, capable of initiating ignition attacks from extreme distances, ensuring the vessel's crew remained safe.

When engaging fleets, the Superheavy Composite Beam Turbolasers employed auto-fire to either penetrate a single target or sweep across multiple targets with a cutting beam. If equipped with Orbital Bombardment Particle Cannons, the Onager would prioritize the immediate destruction of the most threatening enemy vessel. The primary armaments demanded a significant power supply, rendering the power conduits vulnerable to attack. A focused strike that destroyed the main weaponry could trigger a catastrophic failure of the ship's systems, resulting in critical damage or complete destruction.

The Onager-class also featured a variety of ship-based weaponry along its hull ridges on the port and starboard sides, as well as near the hangars in the pronged sections of the ship. These additional armaments comprised six twin heavy turbolaser batteries evenly divided between the port and starboard sides, twenty-four heavy turbolaser batteries equally distributed on both sides, and twenty point-defense laser cannons evenly placed on the forward, port, starboard, and aft sections of the vessel.

The Galactic Empire employed the Onager-class Star Destroyer, shrouded in secrecy, as a specialized orbital bombardment platform deployed at long range. Its initial purpose was to decisively overcome the robust planetary shields deployed by Separatist holdouts, revolutionary Core Worlds, and other dissenting planets. During orbital strikes, it targeted the shield generator and other ground-based defenses. As an uncommon vessel, it was deployed for specific operations. It was also used in anti-fleet actions, targeting the largest enemy vessels. Typically, it was escorted by other vessels to protect its flanks, and it deployed its starfighters to defend its bow from critical strikes by attacking fighters.

The Rebel Alliance believed that the Siege Breaker, if their intelligence was accurate, served as a mobile cannon. Deployments of Onager-class Star Destroyers in sensitive Imperial operations were characteristically unconfirmed or denied, unlike the more common Victory-class and Imperial-class Star Destroyers. Given its capability to destroy a base from orbit or penetrate a cruiser's defenses, the Siege Breaker was considered a valuable addition to fleets. Despite the Death Star's prominence as a symbol of Imperial power, it was not the Empire's only superweapon, as the Onager-class remained concealed and was potentially an even greater threat.

The development of the Onager-class was apparently underway by the end of the Clone Wars. In the aftermath of the war, the Galactic Empire sought a warship capable of efficiently shortening costly and protracted planetary sieges. Consequently, the Empire rapidly developed the Onager-class Star Destroyer to aggressively engage planetary shields deployed by Separatist Alliance holdouts, rebellious Core Worlds, and other dissenting planets that did not align with the Empire.

Significant credits were allocated to the warship's development, with the Empire seemingly investing more financial resources into the Onager's development than they had previously spent on producing Interdictor ships.

In 0 BBY, during the Imperial Era, the Rebel Alliance began detecting indications of a kyber-crystal-powered superweapon. In response, General Airen Cracken, the Rebel Chief of Intelligence, authorized Major Capin Harinar and Colonel Haxen Delto of the Rebel Alliance Intelligence Service to operate independently and theorize, based on available leads, about the most probable configuration of such a superweapon. Both arrived at differing conclusions.

Major Harinar submitted a report to General Cracken regarding an Imperial project known as Operation: Cinder. Colonel Delto, however, reported to Cracken about a weapon known as a Siege Breaker. His analysis suggested that the Empire could construct thousands of relatively smaller cannons, which the Rebel Alliance labeled Siege Breakers, for the same cost as a single "planet-killer." The document also included potential speculation on the Siege Breaker's characteristics and armament, along with an illustration of the vessel.

Delto used the document to argue that the Siege Breaker was a more likely prospect than a large "planet-killing" battle station. After reviewing both reports from Harinar and Delto, Cracken included them in his own report to Alliance Chancellor and Commander-in-Chief Mon Mothma. The "planet-killer" was eventually identified as the Death Star, a battle station capable of destroying entire worlds. At one point during the Imperial Era, an Imperial moff ordered an Onager-class Star Destroyer to obliterate a city from orbit. In another incident, an Alliance installation was destroyed, although it remained unclear whether the Empire had equipped an Onager-class with a miniaturized Death Star superlaser or if it was a separate event.

It was eventually confirmed that the information gathered by Alliance Intelligence on Operation: Cinder and the Siege Breaker was accurate, including the illustration of the Siege Breaker. While relatively rare, several examples of the Onager existed, including the Rakehell, the Cataclysm, the Sunder, and the Onager-class Testbed. Throughout the Galactic Civil War, which spanned from 4 BBY to 5 ABY, the Onager-class Star Destroyer underwent continuous refinement, with the Testbed facilitating the deployment of the Onager in its experimental form.

The Rakehell was once accompanied by two Victory-class Star Destroyers, while the Cataclysm was stationed near a pair of gravity wells and received a Lambda-class T-4a shuttle and two TIE line starfighters. The Sunder participated in a battle against a Rebel Alliance MC80 Liberty Type Heavy Star Cruiser within an asteroid field and sustained significant damage. The Onager-class Testbed once fired its primary armament at a terrestrial body. On another occasion, an Onager was accompanied by an Imperial-class Star Destroyer, while in separate instances, Onagers fired a Superheavy Composite Beam Turbolaser and an Orbital Bombardment Particle Cannon. In yet another instance, an Onager-class Star Destroyer suffered a direct hit on its ventral reactor, causing its superweapon to erupt in flames that engulfed the vessel's hull.

The Onager-class Star Destroyer remained operational following the pivotal Battle of Endor, which resulted in the destruction of the second Death Star and the demise of Emperor Palpatine. It was still considered to be a relatively new and technologically advanced warship. Despite the Rebel Alliance's victory at the Forest Moon of Endor in 4 ABY, the Onager-class Destroyer continued to operate in secrecy. Imperial forces that survived the Battle of Endor in 4 ABY took steps to consolidate their control over the galaxy and launch a counteroffensive against the Rebel Alliance. The remnants of the Empire believed that the Onager-class Star Destroyer was essential for securing victory in the final stages of the Galactic Civil War.

Colonel Delto's report on the Siege Breaker was included in The Rebel Files, a physical data archive containing a non-electronic copy of sensitive information. This physical archive was buried on the Mid Rim world of Durkteel during an Imperial bombardment. The depository was excavated in 34 ABY and soon reached General Leia Organa of the Resistance, a private military with roots to the Rebel Alliance and supported by some members of the New Republic. At that time, the Resistance was locked in a Cold War with the First Order, the successor government of the Galactic Empire. Resistance Major Caluan Ematt reviewed the documentation related to the Onager-class Star Destroyer and left a written annotation.

Major Ematt wrote on the document in The Rebel Files that detailed the Onager, believing that was what the First Order was involved in, and that it would represent a more containable risk. The concept of using heavy armament for orbital bombardments and long-ranged naval warfare was implemented into the First Order Navy's Mandator IV-class Siege Dreadnought. Following the First Order-Resistance War in 35 ABY, the historian and Resistance paramilitary member Beaumont Kin mentioned the Onager-class Star Destroyer in several instances in his book The Rise and Fall of the Galactic Empire. Kin cited Kuat Archives, Section: Imperial Contracts, File: Onager-class Star Destroyer for the research in his book. Kin mentioned that Rebel Alliance records suggested that few Onagers saw service in the war, though Kin believed that it was possible that technological developments were later incorporated into the First Order and Final Order.

The Siege Breaker, later known as the Onager-class Star Destroyer, first appeared and was described in the 2017 boxset and reference book Star Wars: The Rebel Files. Daniel Wallace authored the book, and Diogo Costa created the image of the Siege Breaker. Fantasy Flight Games identified it as the Onager-class Star Destroyer in a news article dated August 1, 2019, which announced the upcoming Onager-class Star Destroyer Expansion Pack and Nadiri Starhawk Expansion Pack for Star Wars: Armada. Both expansion packs were released on January 31, 2020. The company's Starships and Speeders sourcebook, a February 28, 2020 Star Wars Roleplaying supplement, also refers to the starship as the Imperial Siege Breaker.

Leland Chee, an executive at Lucasfilm Story Group, confirmed on Twitter that the design of the Onager-class for Star Wars: Armada came before its narrative development. Chee explained that the Onager-class was initially designed for The Rebel Files. Fantasy Flight Games was drawn to the design and further developed it for their product because it was both visually appealing and fulfilled a gameplay requirement. The term "onager" (ˈɑnədʒər) refers to a type of Roman siege catapult weapon in both English and Latin. The name was inspired by the Syrian wild ass because of the similarity between the animal's kicking motion and the weapon's operation.

• Star Wars: The Rebel Files (Initial mention)

• A New Age of Battle on Fantasy Flight Games' official website (backup link) (Initial identification as Onager-class Star Destroyer)

• The Siege Breaker on Fantasy Flight Games' official website (backup link)

• Star Wars: Armada — Onager-class Star Destroyer Expansion Pack

• Starships and Speeders (Initial identification as Imperial Siege Breaker)

• Star Wars Starships & Vehicles 4 (Starships and Vehicles: Star Destroyers and Siege Dreadnoughts)

• " Starships of the Empire and the Rebellion " — Star Wars Encyclopedia

• Star Wars: The Rise and Fall of the Galactic Empire

• Star Wars: Unlimited — Jump to Lightspeed (Card: Direct Hit (Standard)) (SWUDB backup link)

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• Onager-class Star Destroyers

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