Cobbled Bits of Bone is a book found in The Brigmore Witches.
[Excerpt from a journal covering various occult artifacts]
They say my mother was a witch, but the truth - as is so often the case - depends on perspective and your place in the world. She relied on poisons made from exotic herbs and the blowfish that live in the reef-waters near Pandyssia. Her power originated in hallucinogens delivered through guile or by force to those who crossed her. There was an unusual intensity in her gaze for certain, but it came from within, not from the Outsider. It's what happens to anyone pushed to the absolute edge of sanity and survival, who stays there for years then returns to walk among the sheep in so-called civilized society. My mother was crafty, but if it was anything more than powders, hidden knives, and guile, I never saw it.
Like they tell children, some of those truly touched by the Black-eyed Bastard can move through the space between rooftops like a sparrow. Others command armies of rats or poisonous flies as easy as they wriggle their fingers and toes. The Overseers are right to fear us, to warn the common folk to stay near their homes at night and keep their families close.
But there are other ways His influence manifests itself. Those who serve me share in some of what I can do, and I suspect it's the same for Delilah Copperspoon's coven. Then there are those who can craft runes and charms. The old woman across town - they call her Granny Rags - she carves and polishes the bones of whales, stringing them together and opening them to the Void until they moan like fever-sick on a cold night. I've found a few of her talismans, and with each one I touched, a tiny piece of me departed and settled in with her. What does she gain? A longer life? Some other kind of power I don't understand? The making of things is beyond me.
I've known four people in my time who carried the Mark of the Outsider, but I've known dozens more who wanted it, who stood at night in stagnant ponds or begged with the dust blowing through graveyards. People who gutted farm animals or burned the flesh of men, thinking it would call forth the Void. I met a dying man once who had collected runes and charms for years. He crushed them all into powder, made a paste and ate them, thinking he could gain whatever magic was in the things. His death was long and painful. I also knew a woman from Karnaca who would trade for charms and other bits of whalebone. She cracked them apart and fused them back together, then sold them. I bought one of these corrupted charms that she swore would cause sharp metal to break on my skin, and it worked. But each time it did, one of my teeth turned black and fell out. After the third time, I gave it to one of my men. Now when he smiles, it's all bleeding gums, and I wonder what parts inside him are turning black.
Sometimes I ask myself, without these gifts, would I be a man to fear? Would I be called the Knife of Dunwall, with my name whispered through the markets and the alleyways, the high towers and drawing rooms? I'd like to think so, but it really doesn't matter. As long as I bear this Mark, I'll use whatever craft I have to force my will on the world. The harder trick is undoing what I've done.
It can be found on Daud's bookshelf in his quarters.