The Dread Masters emergency was triggered by the Dread Masters' flight from their imprisonment on Belsavis, coupled with their desire for complete control. Around 3641 BBY, the Dread Masters were liberated and rejoined the Imperial ranks. However, following the Sith Emperor's demise during the Dromund Kaas conflict, they decided to pursue their own agenda, independent of the Sith Empire. This led to numerous confrontations involving the Empire, the Galactic Republic, and the Jedi Order. After several setbacks, the Dread Masters were compelled to establish their final stronghold on Oricon for a decisive offensive.
After the Dread Masters employed the Force to manipulate the minds of both sides, causing widespread insanity, the Republic and the Empire temporarily put aside their differences to face them. Ultimately, an assault on Oricon resulted in the deaths of all but one of the Dread Masters, who was captured by the Republic for Jedi treatment.
The resolution of this crisis allowed both factions to redirect their resources to the ongoing war, as the Dread Masters' threat had previously forced a temporary halt to their respective campaigns.
The Dread Masters consisted of six extremely powerful Sith Lords who reported directly to the Sith Emperor. They earned their titles by mastering the power of the Phobis devices. However, in 3668 BBY, the Jedi Knight Jaric Kaedan apprehended them, and the Galactic Republic oversaw their confinement on Belsavis. To alleviate concerns about their potential escape or misuse of their abilities, the Jedi Order quickly announced the Dread Masters' deaths.
Around 3641 BBY, an Imperial strike force infiltrated "the Tomb," a location deep within the prison on Belsavis, to liberate the Dread Masters. This allowed them to return to Imperial service. However, the Sith Emperor's death during the battle on Dromund Kaas prompted them to initiate their own schemes, which put them at odds with the Empire.
Their initial plan to dominate their adversaries commenced on Belsavis itself, where the Dread Host unsuccessfully attempted to seize control of an ancient Rakatan weapon known as the Aurora Cannon in Section X. However, a strike team dispatched to Belsavis thwarted their efforts. Their second plan involved hiring mercenaries on Denova to aid them and serve as their representatives. Their third plan involved activating a Gree hypergate on Asation to summon a creature known as the "Terror from Beyond." However, this effort failed when a strike team managed to force the beast back into the hypergate.
The Sith Lord Tagriss, who had joined the Dread Masters, was tasked to assault the Arcanum space station in the Meram sector in order to steal dangerous Sith artifacts. Following the death of Darth Karrid, Darth Acina, who had recently joined the Dark Council, dispatched a small Imperial task force to defend the space station. Simultaneously, Jedi Master Cedral Gend sent a Republic team to prevent the theft of the artifacts, which both sides sought to recover.
Amidst the ensuing chaos, Tagriss evaded his pursuers and successfully retrieved the Seeds of Rage and the Darkstaff before fleeing. He escaped to an old Jedi temple on Ilum, where he attempted to unlock their power. However, he was killed when a strike force located and engaged him in combat. This thwarted the Dread Masters' quest for important Sith artifacts and allowed the strike force to recover the stolen relics.
Styrak, one of the Dread Masters, grew increasingly frustrated with his colleagues' failures and displeased with their thwarted efforts. He went rogue and attempted to assemble a team of mercenaries to impersonate the Hutt Cartel in order to achieve his own goals. Despite his hopes for secrecy, a joint Sith and Republic task force discovered his plan and killed Styrak and his followers.
The situation began to shift, and the Republic soon learned that the Dread Masters had retreated to their base on Oricon, a planet located on the edge of Imperial territory. Six hours later, the Republic dispatched a task force to bombard the planet from orbit in order to quickly eliminate the threat. However, the Dread Masters were prepared and used the dark side to project images into their opponents' minds, instilling fear and terror. Supreme Chancellor Leontyne Saresh was compelled to summon other critical Republic forces to join the surviving task force members in order to confront the threat collectively.
Shortly after, the Empire discovered that Oricon was the Dread Masters' base and learned of the Republic task force's fate. Darth Rictus assembled a team led by Lord Hargrev to locate and defeat the Dread Masters on Oricon. However, this team suffered the same fate as the Republic's forces, prompting Darth Marr to dispatch his own vital Imperial forces to locate and assist them.
Ultimately, both sides formed a temporary alliance to defeat their common enemy, crippling the Dread Host to weaken the Dread Masters and assault their fortress. The team initially confronted Dread Master Brontes and her two creations. Her death allowed the team to discover a portal leading to the Dread Masters' lair. The strike force located them in a throne room and engaged the four remaining members. The Dread Masters summoned the spirits of their deceased comrades to aid them in the battle, but the task force's resolve and strength surprised them, leading to increased desperation. Each Dread Master was killed during the encounter, breaking their hold on the minds of the Imperial and Republic soldiers on the planet.
Following the battle, Calphayus, who was revealed to have survived the attack on his former sanctum, stumbled upon the Imperial and Republic team, having sustained injuries. However, Jedi Master Ogan-Dei determined that the former Dread Master was broken and no longer posed a threat. The Republic took him into custody, as Ogan-Dei hoped that the Jedi could provide treatment on Tython.