Dishonored: Brigmore Witches DLC -
After killing Corvo, Daud will wake up and realize it was a dream. Activate your Void Gaze and open the chest below Daud's bed. You'll find some ingots inside and a corrupted bone charm.
Now corrupted charms only exist in this DLC, they're like normal bone charms except they have a consequence, or a condition for using them. For example the Zephyr charm increases your movement speed at the cost of taking more damage from enemy blows. So use these wisely whenever you find them.