This guild is all part of the Fictional World of the Role-Playing Series of the Elder Scrolls and is completly fiction

The Dark Brotherhood is a guild of assassins shrouded in shadow and mystery. The guild originated from the Morag Tong, a religious order during the Second Era, worshipers of the daedra Mephala. The guild has been led by the Night Mother (either male or female) since their early, more disorganized, days. The brotherhood remained mostly ignored until 2E 324 when they murdered the Potentate Versidue-Shaie in the Elsweyr kingdom of Senchal, painting the words 'MORAG TONG' on the walls with his blood. The brotherhood was outlawed across Tamriel and no more was heard from them for 100 years, until they first emerged as the Dark Brotherhood. The Brotherhood was first mentioned by the journals of the Blood Queen Arlimahera of Hegathe which dates the guild at around 2E 360. The Brotherhood was different than the Morag Tong as they viewed themselves more as a business than a cult. In 2E 430 they were involved in the murder of the Potentate Savirien-Chorak and all of his heirs, thrusting Tiber Septim into reign. Today the Brotherhood can be found all over Tamriel and, although their business is certainly not legal, they are almost universally tolerated. Whenever an individual with legal authority takes an interest in their dealings, the Brotherhood relies upon a combination of bribery, blackmail, coercion, and murder to keep their activities hidden.

To join the Dark Brotherhood you must murder someone in "Cold Blood". Once you have done this, they say that, in your sleep a Dark Brotherhood speaker comes to you in the night and offers you membership into the Dark Brotherhood if you kill someone for them. *In Elder Scroll IV Oblivion Dark Brotherhood Speak Lucien Lachance comes to you and asks you to kill a man named Rufio at the Inn of Ill Omen.*

Once you have joined the Dark Brotherhood you must abide to The Five Tenets which are as follows

1. Never dishonor the Night Mother, To do so is to invoke the Wrath of Sithis

2. Never Betray the Dark Brotherhood or its secrets, To do so is to invoke the Wrath of Sithis

3. Never Disobey or refuse to carry out an order from a Dark Brotherhood superior, To do so is to invoke the Wrath of Sithis

4. Never kill anothe member of the Dark Brotherhood, To do so is to invoke the Wrath of Sithis

5. Never Steal from another member of the Dark Brotherhood, To do so is to invoke the Wrath of Sithis

If you do break any of these rules when you sleep you will be visited by "The Wrath of Sithis" A powerful ghost, if you manage to defeat it, you will be permitted to rejoin the Dark Brotherhood.

The rankings of the Dark Brotherhood are as followed, starting with the lowest

Murderer, Slayer, Elimanator, Assasin, Executioner, Silencer, Speaker, Listener

Now let me explain the duties of these rankings... Up until the rank of Silencer you mainly take contracts from the leaders of your sanctuary, eliminating anyone you are told to kill. Then once you reach silencer you either directly serve or are a part of what is called "The Black Hand" The Black Hand are the leaders of the Dark Brotherhood, It is made up of 4 Speakers and a Listener. "Four Fingers and a Thumb is you will" Quotes Dark Brotherhood Speaker Lucien Lachance.

The Speakers job is to recruit new members into the Dark Brotherhood, they are the ones who visit you when you kill someone. And the Listener is the direct leader of the Dark Brotherhood and recieves orders from the Night Mother herself. This is mostly common knowledge of the Dark Brotherhood members.

However what is secret to most is that each speaker has its own personal assasin called a Silencer. Like the nail of a finger you could say. The are meant for the most deadly of jobs and require Masters of Decieption.

The Dark Brotherhood answer to noone but Sithis and the Night Mother and exist throughout Tamriel... killing without mercy.