The Witcher 2: Assassins of Kings[]
Diagram: Black Unicorn is a crafting diagram in The Witcher 2: Assassins of Kings that is needed to craft Black Unicorn. It is only available in Dark Mode.
The Witcher 3: Wild Hunt[]
Diagram: Black Unicorn returns in The Witcher 3: Wild Hunt.
After reaching level 30, It's a possible spawn at a random diagram location and some caves in Velen and Skellige.