The insidious Devil of Secrets had created a vile and ancient form of magic known as Soul Puppetry.
This high-level magic allowed the caster to implant arcane parasites into their target's soul, threading invisible cords through their thoughts, emotions, and will.
The victim often remained unaware, believing every action was their own… until it was too late.
Or, in other cases, the soul body of the victim was completely replaced by the parasite, allowing the caster to gain full control over them.
The first step was to have the arcane parasite secretly burrow inside the target's spirit sea. From there on, the caster could choose to have the parasite operate in one of two ways.
Either, it could subtly influence the target to act in ways that would be beneficial to the caster. This method was a subtle for of manipulation where the victims would end up carrying out tasks without even knowing they're no longer free.