True Faith

[Bruce Coulson]

Yes; if you just take Thaumaturgy you'd be a Focused Practioner (technically).  You work primarily in saving souls possessed by demons and other entities; there's no need to throw lightning or fire around (not to mention what that might do to the host body).

[Encryptedmind]

So how many points would that be?
The true faith takes min 2 up to 4
What does focus practitioner take?

[Bruce Coulson]

The Focused Practioner takes at least one (1) Spellcasting talent; Rituals (-2), Chanelling (-2), Evocation (-3), or Thaumaturgy (-3).  So, you take your minimum True Faith powers (-2), and Thaumaturgy (-3) and you're good for a feet in the water-level campaign.  More refresh/higher power campaign means more powers, more stunts; or just more Fate points at the beginning.

If your GM will let you take Rituals with the focus of Banishing, then it's only -2 Refresh.

Anyway you look at it, this is a quite reasonable starting character for DFRPG.