The Knife of Dunwall is a book found in Dishonored 2.
[Excerpt from a Penny Novel]
Daud stared at the blade. The plan had gone perfectly, even better than he could have hoped. In fact, the whole thing had been too easy. But now that was over, he felt hollow, and there was nothing in the world that could fill him again. He knew it with a certainty that scared him.
Billie called from the next room. "Boss?"
"Leave me." He nudged the door closed before she could say anything else. He trusted her more than any of them, but he didn't feel like talking.
Cleaning the blood from the blade, he studied the marks it made on the cloth. Royal blood, but it looked the same as any he'd seen before. Weren't the high and mighty supposed to be filled with something different? Something better?
Daud was tired. No amount of blood could change the way he felt. He didn't drink as a general rule, and sex had never interested him. He felt a kind of exhaustion that couldn't be soothed away. A smile crept across his mouth. The Knife of Dunwall, exhausted. And yet something else. What was he was feeling, exactly?
He'd looked into Jessamine Kaldwin's eyes at the moment her life slipped away. And in that moment a thought occurred to him: He'd made a mistake. He'd been misled. That kind of thinking was useless. She was just as dead, whether he regretted it or not. But he'd seen his true face reflected in her eyes; seen himself for what he really was. Not a renowned assassin, not some great shaper of history. Just another playing piece in an unknowable game.
The book can be found on a shelf on the top floor of an abandoned building opposite the City Watch Armory during the mission A Long Day in Dunwall, and in the room of Claudio, an admirer of Daud, during the mission The Grand Palace.