So, let's look at reskinning the "Hexen..." as "Blessed..." (not necessarily by Michael Carpenter's boss... but by an entity that is more-or-less benevolent).
Maybe someone Shamanic produced a "Quester's Mask" -- a ceremonial dance-mask in the form of an eagle, raven, etc; with an associated spirit. It drives you to complete some great quest, a fundamentally "good" quest, but at some personal risk (you may end up with the fierce Eagle territoriality, with the acquisitiveness of Raven, or whatever). Ultimately at risk is you becoming a magical entity, a servant (a zero/negative Refresh NPC, in DFRPG terms) of the Great Spirit involved. We can also borrow from the "Lawbreaker" mechanism -- you've "bought" (with Refresh) some abilities that have taken you to NPCland.
Maybe some wiccan sort, with the "GreenMan" image in mind & a few too many viewings of LOTR movies thought "Ya know... I think I can MAKE an Ent, to protect that endangered old-growth forest..."
Etc.
Fundamentally, I think, you're looking at magic that *must* place the character at-risk of NPC-hood (from the POV of DFRPG and the Dresdenverse in general). They may exit PC'dom by becoming a good spirit in the service of a Great Spirit (instead of an evil Hexen-something-awful), but if they keep using the item their humanity & free-will eventually get lost in the power.