The Morag Tong is an ancient guild of assassins headquartered in Morrowind, glorifying murder in the name of Mephala. They have been operational since the First Era, and their targets have included multiple rulers of Tamriel, high-ranking Dunmer elite, and innumerable others. The Morag Tong is distinctive in its endorsed status under the Morrowind government to conduct legal executions, bound under agreements called 'writs.' However, extralegal 'gray writs' are whispered to exist.
The origins of the Morag Tong are surrounded by myth. The orthodoxy of the Tribunal holds that the Daedra Mephala established the guild to train the early Chimer on how to defend themselves and destroy their enemies. Others state it began as a cult which, while also following Mephala, ultimately revered the 'Dread Father' Sithis above all. However it began, the guild rose to prominence in the circumstances of early Morrowind's bloody House conflicts, quickly establishing the writ system and a reputation as peerless killers.
At the end of the First Era, the Tong accepted its highest-profile contract to date on Emperor Reman III. Their success paved the course for the Akaviri Potentate to govern over Tamriel in the early parts of the Second Era, as the Tong gradually expanded its presence across Tamriel. It came full circle when, in 2E 324, Versidue-Shaie was assassinated by the Tong. By this point, however, the guild was over-confident and prideful, and 'MORAG TONG' was scrawled on the palace walls in the Potentate's blood.
This high-profile assassination started an uproar among the nobles of Tamriel, who discovered that they too were at risk from the Tong. "Every sovereign gave the cult's elimination his highest priority," and it was viciously quashed in every region of the Empire, only maintaining the barest presence in its homeland of Morrowind. After this, the Morag Tong sunk out of public sight for almost a century. During this time, most agree the Dark Brotherhood arose as a splinter group, establishing itself primarily outside of Morrowind as a more business-oriented guild functioning entirely outside the law.
While the Dark Brotherhood rose to more renowned prominence elsewhere, the Morag Tong maintained a formidable presence in Morrowind. Reports indicate they gave up the worship of Mephala in exchange for revering the god-king Vivec. However, they preserved their worship of Sithis. Despite the shared service to Sithis, they were mortal rivals of their old splinter group, the Dark Brotherhood, who revered the Night Mother. The Tong maintained its original function of the First Era: that of a nonaligned middle-man in the frictions between the Great Houses in the bloody business of Dunmeri politics. Some within the faction, however, felt that their services were undervalued as wealthy nobles with petty grievances used the Tong too freely, not respecting the ancient institution; however, they did not act outside of Morrowind, nor did they interfere in politics higher than that of inter-House rivalry. Nor did they act on their own account, except against the Dark Brotherhood or worshippers of Mehrunes Dagon. Indeed, sometimes they were hired to track down and kill lawbreakers as an alternative to the more customary Fighters Guild bounty.