The Dread Masters were six powerful Human Sith Lords who served the Sith Emperor for centuries as prophets, generals, and advisers. Their names were earned when they studied the power of the Phobis devices, artifacts that had driven even the most depraved Sith mad with terror. This power allowed the Dread Masters to destroy entire Galactic Republic fleets during the Great Galactic War; they had mastered the art of battle meditation to the point that they would inflict an awful, mysterious terror upon members of any given Republic cruiser. In order to avoid being compromised, they kept in constant motion in an Imperial dreadnaught that roamed the galaxy. With the help of an elite Republic Special Forces Division team, Jedi Knight Jaric Kaedan infiltrated the dreadnaught and captured the Dread Masters. The Jedi Order publicly announced that the Dread Masters were killed, but secretly they were imprisoned on Belsavis.
Released by servants of the Sith Empire, the Dread Masters went rogue following the defeat of the Emperor on Dromund Kaas, forming an empire led by their own Dread Council. After one of their members was slain on Darvannis, the remainder relocated to their Dread Fortress on Oricon, where they were defeated in 3638 BBY. Dread Master Calphayus was the only one who survived the downfall of the others, and was taken once more into Republic custody.
The Dread Masters were first introduced in the 2011 video game Star Wars: The Old Republic. Their original character models featured helmets and robes that were also attainable by player characters as wearable armor. In 2012, their appearance was updated to feature new helmets that were not available to players, though, by 2014, a variation known as the Crest of the Dread Master became available.
Freeing the Dread Masters is the ultimate goal of the Belsavis story arc for Imperial characters. They go on to serve as major antagonists in the post-story content of Star Wars: The Old Republic. Chronologically, their uprising occurred in an interlude between the character story lines and the Rise of the Hutt Cartel.