Ashes of War are special items that allow you to change the active skill of your weapon. Thanks to them, you can exchange your weapon skill for a completely new one. You activate them by pressing the button responsible for using skills. Spirit Ashes, on the other hand, are items that, when activated, summon spirit companions that will help you in combat.
Travel to the area marked on your map. The ash can be obtained from an invisible scarab that leaves snow marks. Watch out for a pack of wolves that are very close to this location.