You have discovered fell spirits contained in Angmarim crystals in Mullach Cagar.
You found a crystal apparently left behind by one of the Angmarim, possessed of a foreboding aura. As you pick it up to examine it more closely, you think you can hear a tapping sound emanating from inside, and a quiet whispering. It seems likely the Angmarim priests use these crystals to hold fell spirits before they find suitable corpses for creating wights.
If you destroy these crystals, the fell spirit might be more easily banished.
Glowing crystals can be found in Mullach Cagar.
You should destroy these crystals and defeat the released fell spirits.
You have defeated many fell spirits in Mullach Cagar, preventing them from being used to make wights.
You should report to Molkha in the valley.