I have been observing this macabre army of, wood, flesh and bone and how the witches and servitors control the lesser creations with charms. I believe I can craft an even more powerful charm - one we can use.
In the hearts of the servitors are the very strongest charms. They are used to anchor the Ancient Drust into their physical forms. They are precisely what we need.
Good luck. It is doubtful that they will part with them easily.