"Mine is the face of blood and fire."
-The Sickness (Blackwing Virus), as experienced by Dail'Liss
The Imperial bioweapons Project I71A, known as the Sickness and Blackwing Virus respectively, was an infectious viral agent created through the powers of Sith alchemy that attacked biological tissue and transformed its victims into undead monstrosities. The disease was originally created by the Sith Lord Darth Drear on Odacer-Faustin sometime prior to 3232 BNE, and was intended to grant immortality to its crafter. Drear's initial experiments resulted in failure, and the Sith Lord himself fell victim to his creation. Over one thousand years later, during the period of unrest following the Great Galactic War, the Sith Lord Darth Scabrous attempted to recreate Drear's disease in the hope that he would be able to succeed where his predecessor had failed. Scabrous likewise failed to create a path to immortality, and in the process unleashed the virus upon the unsuspecting students and staff of the Odacer-Faustin Sith academy. Before long, all of the Sith Acolytes and Masters on the planet died and were born anew as cannibalistic monstrosities motivated only by the will to eat.
Knowledge of the Sickness, as it had been known during the Odacer-Faustin outbreak, survived several millennia and eventually fell into the hands of Darth Vader, a Dark Lord of the Sith alive during the reign of the Galactic Empire. Around 1413 NE, Vader commissioned a scientific team from the Imperial Biological Weapons Division aboard the Imperial I-class Star Destroyer Vector to re-engineer the virus and turn it into a weapon that could be used to further Imperial interests. Operating in secrecy, the scientists were able to recreate the disease under the codename "Blackwing" and prepare it for deployment. However, in that year, an accident aboard the Vector unleashed the Sickness once more, turning almost all of the personnel aboard the vessel into savages not unlike those on Odacer-Faustin. The infected took control of the ship and used it to cripple the Imperial prison barge Purge, thereby forcing the barge's occupants to enter the Star Destroyer and become prey for the Sickness.
The disease itself was created through the usage of Sith Alchemy and activated by the Murakami orchid—a highly-Force-sensitive black flower. Victims of the plague suffered numerous, extremely painful side-effects prior to death, and became mindless monstrosities postmortem. The virus itself was fully self-aware, and utilized the undead to spread the pathogen and either transform or eat any who were able to avoid infection. Due to the extremely quick rate of transmission and the difficulty of isolation, successful treatment of the disease was very rare; although one could be prevented from contracting the virus by injecting an anti-virus intravenously, those who were already infected had little chance of survival. The fluid that coagulated within the bodies of the infected and carried the virus throughout their anatomy bore many similarities with the entity known as Mnggal-Mnggal, leading some to believe that the two were in some way related.