Memory Crystal (Part 3)
Back when Balkor had developed memory crystals to guide his thralls, he hadn't had to deal with conflicting willpowers since what he imbued them with was his own personality. The limit of his memory crystal was that they couldn't be used by other people and that the knowledge stored inside of them didn't last for long.
Balkor's method consisted of storing the crystals inside a powerful array that insulated them from the world energy. The gemstones were left with nothing to feed on but the magical formation which was fueled by Balkor's mana.
The world energy stored inside the crystals would be slowly replaced by his spell that was imbued with his willpower, grudge, and anger, turning them into memory crystals.
The problem with this method was that once the crystals were removed from the arrays, the natural flow of world energy would be restored, flushing the mana out.