Onager-class Star Destroyer

The Onager-class Star Destroyer, nicknamed the Imperial Siege Breaker by members of the Rebel Alliance, was a type of rare capital ship and superweapon deployed by the Galactic Empire that was shrouded in secrecy. Initially developed to swiftly eradicate Separatist holdouts that remained after the Clone Wars and to bring Core Worlds under the control of the Empire, the Onager-class saw service throughout the Imperial Era. By the time after the Death Star was active, the Onager was considered to be a possibly greater threat.