Runes — mystical objects from whale bones, which are artifacts in Dishonored 2. Their presence allows you to open a new and improve existing skills. You can either look for them all over the map, and craft then.
Procedure for crafting:
Open the menu
Go to the slots selection capabilities
Select craft bone amulet
Last skill allows to craft runes
All you need to do more — to handle the rune. This can be done as follows:
Go to menu
Select the Bone amulet
Select an option on the right — Bone amulet
Take a look in the same direction and you will see the option of crafting runes
You need raw whale bone to create runes. It can be found, for example, on the black market.