The Harpago functioned as an Immobilizer 418 cruiser under the command of Grand Admiral Demetrius Zaarin when he committed treason and tried to abduct Emperor Palpatine. After the failure of Zaarin's plot to annihilate the Garrett, which was left damaged and unable to return to Coruscant promptly, Darth Vader interrogated Maarek Stele and discerned that Palpatine was at risk. Consequently, Darth Vader chose to fly a TIE Defender, accompanied by the experienced Maarek Stele as his wingman. Serving as an escort, the Harpago, accompanied by several Assault Gunboats, tried to delay Darth Vader's rescue mission from reaching the Emperor. Ultimately, they succeeded in eliminating the escorting fighters and then the cruiser. The destruction of the Harpago enabled Darth Vader to get to the Emperor before Zaarin could take him.