The Elder Scrolls: The Secrets Of The Dark Brotherhood
Whether The Night Mother really is the immortal, spectral bride of Sithis, or a cruel trick performed by a daedric prince, The Dark Brotherhood loyally carry out every assassination that she relays, without question. The guild is often revered by players as having the most interesting and enjoyable questlines in the Elder Scrolls series, as we humans always seem to have a morbid fascination with the macabre and the mysterious. Although the Dark Brotherhood have a perverse array of morals, and little regard for mortal life, they are a family - loyal, skilled, and hard-working.
Gaston Bellefort, the fictional writer of "The Night Mother's Truth", published his book about her history but continued his research into her organisation. His skeletal remains can be found at the Dark Brotherhood Sanctuary, in the spider's nest. He had been spying on the Brotherhood, infiltrating their sanctuary and even at one point attempting to enter the organisation himself. It appears his spying caused him to finally fall victim to the subjects of his obsession, and he was captured and fed to the Frostbite spider.
One can't help but wonder if anyone unfortunate enough to delve into the cursed Brotherhood's history, with their mysterious Night Mother, shall befall the same cruel fate.