Black Bonecharm Notes is a written note found in Dishonored 2.
Transcript
5th
I've set out to craft a new bonecharm, and I hope to have it blacken, in keeping with those of greater power. It will complement the one I've carried since finding it within a mausoleum in Alba. Though it's rare to meet others touched by the Void, summoners beware, for as long as I carry that bonecharm, their rats and vermin will turn against them. And the new charm, if it works, will shield me against assassins.
11th
I am still working on my protective charm. I've taken the Tyvian Grey Bone recipe and altered it, using much more burdock root. The instructions were vague and the safeguards it offers are weak.
18th
Neither chamomile nor nasturtiums added to the mix give me the right effect. Though they perfume the air quite nicely. I feel well protected from unpleasant smells, but not much else.
23rd
I've finally got it! Hellebore of course, fermented and reduced over a low flame. It's rare to achieve this effect, where the bonecharm turns darkest black. As I wanted, I'm warded against the first bullet or bolt from an assassin's weapon. The initial shot that would fell me instead change to bloodflies in an instant!
Location
The note can be found in Breanna Ashworth's Office in the Royal Conservatory, during the mission The Royal Conservatory.