Third Jedi Purge

The Third Jedi Purge was an attempt to eradicate the New Jedi Order, instigated by Darth Trayus and his Sith Brotherhood in order to impose the Dark Lord's will on the galaxy. The crusade was later joined by the Shadow of the Sith and the Order of the Sith Lords, which together formed the Sith Triumvirate.

Origins
"For, in the end, all will either serve me, or be destroyed. Those whom have betrayed me must be the first to pay the price."

- Darth Trayus

The Third Jedi Purge began with Darth Trayus's quest for vengeance against the Jedi Order for its betrayal against him. The Kora Jedi Council, believing that his pursuing Sivter after he killed his father would result in Cadden's fall to the dark side, denied him any resources to find and kill the Defel dark lord. Infuriated, he stormed out of the Jedi Council chambers and, with Darth Invictus's help, recruited several Jedi to his cause.

Later, following several small-time hunts for random Jedi, Darth Trayus launched his first full-scale assault against the Jedi Order, attacking the City of the Jedi and nearly killing Cazzik Wyn. This act, however, sparked something even more sinister within the Dark Lord of the Sith.

The Purge Begins
Dissatisfied with his minimalistic victory, Trayus began to work to find more effective ways to destroy the Jedi Order. He instigated a series of kidnappings on Jedi across the galaxy in order to test his new anti-Jedi droids, as well as the Cybrid models to follow. These kidnappings also held the dual purpose of learning about the Jedi Order itself; its strengths, its weaknesses. Few of these Jedi survived these experiments. Those that did either went on to serve him, or he used in far more sinister ways.

When the time was right, Trayus chose to finish what he began at the City of the Jedi, and launched a second attack on the world, this time laying it to waste, and sending a message to the Jedi Order that it could not hope to stand against the coming darkness.

Following the successful battle, Darth Trayus sought out two powerful alliances in the Shadow of the Sith and its puppet government, as well as the Order of the Sith Lords, which willingly joined him in his mission, valuing the same objectives Trayus sought after in the alliance.