Resurrectionist are Walkers who specialize in the retrieval of corpses or bodyparts for the purpose of ritual and magic.
Spooks are wizards, warlocks, and witches who use their magic for a corporate or government peycheck. They are the MiB, the web of conspiracies, the poor bastards who has to go out and get that rampaging monster.
Mules are magi who settled on a career of ferrying goods between dimensions instead of going poking around ancient terrors and reality-rending disasters.
