There are many horrible ways to reanimate someone who's died, or to enslave the living to another's will. This does not seem to be any I am familiar with.

[And he'd been possessed, turned into a robot and revenant, which covered most of the terrible things that could happen to a person in his world.]

If it is, there does not seem to be a point to our existence here. Unless it's a holding area until whoever has done this has need of us. But it seems ... more mysterious than that.

[Maybe that's wishful thinking.]