You will need:
The items drop from Dreadbone Sentinels, Dreadbone Skeletons, Deathcage Scryers, and Deathcage Sorcerers in the Dead Scar. They are not soulbound and are not quest items (you can collect them when you don't have the quest) as they are also used for the repeatable quest [??] .
The dark energy that flows through the bodies of reanimated skeletons tends to accumulate primarily in their spine. I've discovered a method of instilling this energy into a potion that boosts our magical abilities against the undead.
Bring me some and I'll be glad to provide you with a sample. You'll find an ample number of skeletons wandering the Dead Scar, west of here.
Do you have the samples I requested, <Name>?
Take this, <name>. You'll feel the difference immediately!
Feel free to bring more spinal dust; I can use as much of it as you can provide. Side effects? You might start feeling your joints acting up a bit. Nothing permanent, I assure you!