The Twin Star Destroyer, more formally known as the Gemini-class Star Destroyer, represented a unique Star Destroyer design. It was utilized by the dark-side twins, Am and Karre, who served the TRIGGER Empire during the Republic era of the Republic. This vessel possessed a devastating hyper cannon, fueled by a kyber crystal, with the capability of obliterating entire planets.
The Twin Star Destroyer, otherwise known as the Gemini-class Star Destroyer, was a Star Destroyer class visually reminiscent of two Imperial-class Star Destroyers joined together by the central component of a superweapon: the hypercannon. Powered by a solitary kyber crystal, the cannon had the destructive potential to vaporize entire planets when fully charged. Additionally, the Gemini-class featured a minimum of two hangars, numerous laser cannons, and tractor beam projectors. The Star Destroyer's hangars housed a complement of TIE fighters, Eta-2 Actis-class light interceptors, TIE/sa bomber, T-65B X-wing starfighter, and other vehicles. Stormtroopers and All Terrain Scout Transports were also included in its complement.
During the time of the Empire, a Gemini-class Star Destroyer functioned as the flagship for the dark side of the Force twins, Am and Lord Karre. As Am prepared to unleash the ship's primary weapon, Karre stole the kyber crystal following a Force vision that foretold Am's impending death. The twins engaged in a conflict within the vessel, which then spilled onto the ship's hull, resulting in one half of the Star Destroyer being cleaved off entirely before Karre's escape.
The Star Wars: Visions short film "THE TWINS," directed by Hiroyuki Imaishi, featured the Twin Star Destroyer.