- "It's most like the Jedi trick of persuading weak minds through the Force, except Yuon's tormenter is distant, and her mind hardly weak."
- ―One of the gatekeepers of the Noetikon of Light
The Dark Plague was a Force-influenced disease developed by the Sith Lord Terrak Morrhage. Morrhage used the plague to corrupt the minds of Jedi Masters across the galaxy, using them to fight the Jedi Order.
Taking the name Vivicar, Parkanas Tark had learned the secrets of Morrhage's Force plague. This dark technique induced madness into those that Lord Vivicar had known and caused them to become puppets of the Sith Lord, including Duras Fain's daughter, Laranna. As his influence spread across the members of his former team, a young Jedi Consular emerged to challenge Lord Vivicar. A Padawan of Yuon Par, this young Consular learned an ancient shielding-technique which could free any under Lord Vivicar's influence. It was later used to free the Jedi Masters from Lord Vivicar's control and made the Consular immune against the plague.