Dark Plague

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.

Morrhage was defeated, but during the Cold War, his spirit possessed the fallen Padawan Parkanas Tark, once again using the Dark Plague to corrupt the 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. Symptoms included a conviction "The darkness [was] coming", and a belief that actions the Jedi affected by the disease would normally never commit were needed to stop it. 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.