Hazar Yupcavage, a Regional Director within the Imperial Corrections Service, held the rank of Sergeant and served as the direct supervisor to Warden Bissley Kloth, who oversaw the operations of the Imperial prison barge known as the Purge.
Kloth dispatched a written report to Yupcavage detailing the incidents that transpired when the engines of the Purge failed. Within this communication, Kloth stated that a team tasked with salvaging replacement components from a wrecked Star Destroyer in proximity to their location came back carrying an unusual and contagious ailment, leading to their isolation. Beyond this, the sole utterance the crew could provide to clarify their state was "Blackwing." Since the letter was found on the Purge after the plague had wiped out all of its inhabitants, it's improbable that Yupcavage received it before it was later made accessible to the public for scholarly research concerning the history of the Purge.