The Galactic Republic, in 22 BBY, passed a law controlling the trade of stygium, as it was a crystal that, when used properly, could entirely cloak a vehicle. In the Galactic Republic's early years these devices were common, since Aeten II held an abundance of them. These vehicles included the Scimitar, Darth Maul's ship, which carried an array of stygium crystals in its long prow. Darth Vader's secret apprentice, codenamed Starkiller, utilized stygium crystals in his ship, the Rogue Shadow, which used a cloaking device.