To Daud is a written note found in Dishonored: Death of the Outsider.
Transcript
I used to do this with Deirdre. I wrote her letters for years after she died, and I let every one of them float down the river. Maybe you saw me do it, but you never said anything. It made that time bearable. Grief makes us do strange things. But you know all about that, don't you?
This one might make the wounds come open again, but isn't that what I want? You're not dead. I know that. But you might as well be, for how far away you are. So I'll write down everything I can't say to you and throw it in the sea, just like I used to.
The years since the Flooded District were hard. Building a new name from scratch takes a lot out of you, and now I'm leaving it behind. I wonder if you'll even recognize me. I'm not as young as I was. Well, neither were you, when you went after the Brigmore witches. But that wasn't your last job, either. All the rumors put you right back in it, dealing with the gangs and black markets and bonecharms. What are you up to? What are you doing in Karnaca, when you could be anywhere in the Isles?
I have a feeling that when I find you, I won't like your answers.
Location
It can be found in the water by the Dreadful Wale after the first mission.