Could the Spirit Shaman approach the belief in the spirit the same as what is found in real life Christianity. That in being, the Holy Trinity, where the Holy Spirit (or, Ghost), is found to be an aspect of the God itself and that the believer is aware of this?Spirit Shamans and Deities
Spirit shamans are no exception to the requirement that divine casters have a deity, and they draw their powers ultimately from a god. However, in the case of a spirit shaman, spirits act as intermediaries of this divine power, and it is the spirits themselves that spirit shaman PCs bargain with. While usually a spirit shaman will know the source of his divine powers, it is also open to a spirit shaman to venerate a cause, a broad aspect, or the spirits themselves, without realising that ultimately his or her power is derived from a god.
My character is a follower of Angharradh, which has some mild correlation to the divine Trinity of Christianity and I have often RP'd that the God, while disbelieved by others, in times of crisis will come to her with divine omen. There is the Omen spell which would seem to allow for this. I always contact a DM to ask them their interpretation of this Omen while IG, FYI.