Shamans are the spiritual leaders of the old traditions of the North, the stewards of culture that existed long before the Compact. While any can follow the calling and become a shaman, most believe they have a native affinity with the spirits of the old deep places, and are born with an innate talent that makes a shaman and some speak of a 'Second Sight' that is dismissed by the rest of the Compact as nonsense. Among most of the Northlands however, shamanism is a calling, something inherent in their being that awakens. The basis of this lies in the old superstition that Shamans distinguish two selves within themselves; there is a "spiritual, free soul" and then there is the "mundane soul'. The latter is unable to breach the divide that separates the spiritual from the corporeal, leaving the "free soul" the ruling mind when rituals and acts as Shaman are conducted. While these old beliefs are dismissed by the southern great houses, more than one mirrormask or member of the Faith has remarked upon the similarities in the duality that shamanism espouses compared to the beliefs about the Dark Reflection, and that the spirit realm is similar in theology to the Faith of the Pantheon's 'Shining Lands'.
Shamanism as a religion does not acknowledge any named deities or figures. Their world is one filled with spirits and not always ones that are anthropomorphized, they can be either being or place. Any place, whether it be a long forgotten vale or a small grove, can potentially have its own memory and spirit in Shamanism's eyes.
In short, Shamans act as the mediators between the spirit world and this one. For each favor or boon asked, it is approached as a transaction where a sacrifice must be made. Sacrifice can be a multitude of things, dependent upon the wisdom and gravity of guidance that is being asked of the spirits.
Their worship is one of much mysticism and ritual, meditation and trance. It is the old religion of men that far predates the worship of the Pantheon, long before the great houses came to be, and while its number has grown smaller with the Compact and the people's exposure to other faith, it hasn't and never will be fully surrendered in the North.