Thank you for writing in,
The soul and spirit are two different things. Through the Black Arts (not to be confused with Dark Arts) there is a way to manipulate both the soul and spirit. When someone practices Black Arts it means they are capable of removing the free will of the target, and thereby forcing their own will upon them. In all cases of Black Arts spells & practices there is a price to be paid, and no matter how powerful the practitioner is, they will pay a price.
In both theory and practicality, though the former is far more likely than the latter, it is possible to forcibly trap a spirit and cause it to do your bidding. Further stipulation and action depends entirely on the type of spirit. In all cases the soul moves on, but a trapped spirit is not to be diminished in light of the considered divine aspect of the soul. A trapped spirit is still a horrific state and abominable practice not sanctioned by any practitioner of moral fortitude.