Sileen held a position within the ranks of the Mistryl Shadow Guard. During the year 0 BBY, she was a part of a six-member, all-female warrior squad under the command of Manda D'ulin, functioning as the designated pilot of the Skyclaw, which was one of the team's pair of starfighters.
Although Sileen wasn't immediately on the scene during the stormtrooper surprise attack at the Hammertong facility's entrances that resulted in Team Prime and Pav D'armon being shot down, she gave crucial covering fire when Shada D'ukal opted to strike back. This support allowed Shada and Karoly D'ulin to successfully commandeer a Strike cruiser that was transporting an experimental Imperial superlaser.
After that, Sileen piloted the Skyclaw to Emberlene to acquire a freighter, while Cai and the Mirage took on the responsibility of escorting the stolen cruiser to Tatooine.