The Brothers of Darkness Content . As their name suggests , the Dark Brotherhood has a history shrouded in obfuscation . Their ways are secret to those who are not themselves Brothers of the Order ( " Brother " is a generic term ; some of their deadliest assassins are female , but they are often called Brothers as well ) . How they continue to exist in shadow , but be easily found by those desperate enough to pay for their services , is not the least of the mysteries surrounding them . The Dark Brotherhood sprang from a religious order , the Morag Tong , during the Second Era . The Morag Tong were worshipers of the Daedra spirit Mephala , who encouraged them to commit ritual murders . In their early years , they were as disorganized as only obscure cultists could be due to there being no one to lead the group , and as a group they dared not murder anybody of any importance . This changed with the rise of the Night Mother . All leaders of the Morag Tong , and then afterward the Dark Brotherhood , have been called the Night Mother . Whether the same woman ( if it is even a woman ) has commanded the Dark Brotherhood since the Second Era is unknown . What is believed is that the original Night Mother developed an important doctrine of the Morag Tong , the belief that , while Mephala does grow stronger with every murder committed in her name , certain murders were better than others . Murders that came from hate pleased Mephala more than murders committed because of greed . Murders of great men and women pleased Mephala more than murders of relative unknowns . We can approximate the time this belief was adopted with the first known murder committed by the Morag Tong . In the year 324 of the Second Era , the Potentate Versidue - Shaie was murdered in his palace in what is today the Elsweyr kingdom of Senchal . In a brash move , the Night Mother announced the identity of the murderers by painting “ MORAG TONG ” on the walls in the Potentate ' s own blood . Previous to that , the Morag Tong existed in relative peace , more or less like a witches ' coven - occasionally persecuted but usually ignored . In remarkable synchronicity at a time when Tamriel the Arena was a fractured land , the Morag Tong was outlawed throughout the continent . Every sovereign gave the cult ' s elimination his highest priority . Nothing more was officially heard of them for a hundred years . It is more difficult to date the Era when the Morag Tong re - emerged as the Dark Brotherhood , especially as other guilds of assassins have sporadically appeared throughout the history of Tamriel . The first mention of the Dark Brotherhood that I have found is from the journals of the Blood Queen Arlimahera of Hegathe . She spoke of slaying her enemies by her own hand , or if necessary " with the help of the Night Mother and her Dark Brotherhood , the secret arsenal my family has employed since my grandfather ' s time . " Arlimahera wrote this in 2E412 , so one can surmise that the Dark Brotherhood had been in existence since at least 360 if her grandfather had truly made use of them . The important distinction between the Dark Brotherhood and the Morag Tong was that the Brotherhood was a business as much as it was a cult . Rulers and wealthy merchants used the order as an assassin ' s guild . The Brotherhood gained the obvious rewards of a profitable enterprise , as well as the secondary benefit that rulers could no longer actively persecute them : They were needed . They were purveyors of an essential commodity . Even an extremely virtuous leader would be unwise to mistreat the Brotherhood . Not long after Alimahera ' s journal entry came perhaps the most famous series of executions in the history of the Dark Brotherhood . The Colovian Emperor - Potentate Savirien - Chorak and every one of his heirs were murdered on one bloody night in Sun ' s Dawn in 430 . Within a fortnight , the Colovian Dynasty crumbled , to the delight of its enemies . For over four hundred years , until the advent of the Warrior Emperor Tiber Septim , chaos reigned over Tamriel . Though no comparably impressive executions have been recorded , the Brotherhood must have grown fat with gold during that interregnum . The Dark Brotherhood has no shortage of business opportunities - an " accounting , " I have been informed , is the Brotherhood ' s favorite euphemism for an execution . While they are officially considered an unlawful organization in every corner of the Empire , like the Thieves Guild , they are almost as universally tolerated .