Niles Ferrier's associate, known as "wraith," was a male Defel who collaborated with Niles Ferrier, a ship thief. Ferrier simply called him "wraith".
The Defel successfully infiltrated the Lady Luck, managing to attach a pair of tracking devices: one affixed to the ship's exterior hull and another concealed within the vessel, ensuring its discovery would be unlikely. Consequently, Ferrier was able to tail Lando Calrissian and Han Solo to Pantolomin, which facilitated Grand Admiral Thrawn's acquisition of the Katana fleet's location.
During the inaugural meeting of the Smugglers' Alliance, Ferrier's wraith was present when Imperial lieutenant Kosk and his forces launched an assault. The Defel was positioned against a wall, poised to engage the Imperials upon their entry. (This event subsequently aided Gillespee in deducing that Ferrier and the wraith possessed prior knowledge of the stormtroopers' impending attack).
Subsequently, the wraith covertly boarded the Wild Karrde with the intention of planting fabricated evidence implicating Talon Karrde in the hiring of Kosk and his crew. However, this maneuver ultimately exposed Ferrier as the true betrayer within the ranks of the smugglers. Upon Ferrier's escape, he abandoned the wraith, leaving him to be captured by the Smuggler's Alliance.