I guess I just want to know if there are any rules for demonic possession? I have BWG, MaBu, and MoBu, but I haven’t had any luck finding anything.
Also, under the Exorcist lifepath, a training skill called Exorcist Ritual is listed. However, there is no such skill in BWG. I did find a trait called Exorcism Ritualist. I guess there was just a mistake in the lifepath?
In the Blossoms supplement, there are rules.
Basically, replace one of your Beliefs with the demon’s beliefs. If you play it, you get Artha.
I’ve had people roll their Will vs the Demon’s Will to resist acting on that Belief.
For really simple Exorcism Obs, just use the Demon’s Will as the Ob. Rituals can be used as a Linked test. Magic Incense will add an Advantage Die too. Help works, of course.
I think there are Possessed traits in all of the books and I think they all do different things.
Yah, the trait has different listings in ChaBu, BWG & Blossoms.
I’m going to expect this from all future publications. Especially the Bella Sara game.
There isnt One in mg and fm 
I usually go with a vs. Will test when the possessing spirit wants the PC to do something that the PC doesn’t want to do.
I played a possessed PC last year, and where dramatically appropriate I played the trait, then I earned the Artha for it. It was an Artha mine, chalking up Fate for playing possessed, Persona for pursuing the Belief, and a Deed for fulfilling it [Blossom’s version].
The PC started what will probably be a full blown war in the end, ignored party and personal safety and screwed up prospects for promotion and romance all for someone else’s revenge. It was a great deal of fun, and digging the PC’s way out of the hole he is in will be a lot more fun in future.
This is what I had in mind–some actual mechanics for the possession. In terms of handling the initial act of possession, I’ll probably just go with a Vs. Will. Thanks.