I completed the research, my lord. We can accomplish what you desire.
The spirits of all noble-born warriors will be bound to their liege lord. This process masks the binding incantation as part of the knighting ceremony. The enchantment in the knight's sword and shield compels the spirit to serve, whether in life or death. With this citadel full of willing thralls, Loriasel will never be overrun.
As per your instructions, my lord, I poisoned every apprentice assisting in the binding incantation's devisement. The secret shall be kept between us alone.