The Priests of The One are shaman scholars, showing the way of The Spirit, The One to the people. They do not like being called a church, as history has shown that all churches eventually become organizations and dominant ones.
(Name translates directly from ancient Egyptian as: Strong Protector, the Hidden One.) A mysterious shaman appearing without regard to wheres and whens, upon the divine bidding of other Realms. An entity of legend, belonging to a legendary and ancient sect.
A devoted and zealous priest of the Ice, Irad nevertheless is troubled by the brutal and vicious ways of those who worship it. Rather than crush and destroy the civilized folk of the South in its name, he would rather they be converted to the faith of his people and worship the Ice as their master. This he feels, can only be acomplished if they are encouraged to revere it rather than loathe it. It is indeed ironic that such a gentle and wise man serves the twisted Ice Lord..
Centaur-crafted marching drums, imbued with firey power.
Macu spends his time looking for kind and giving people who he rewards in some small way. He does this by disguising himself as a needy person, maybe an injured traveler on the road, or a beggar in a town. The first person that responds kindly to him will receive some assistance in the endeavors, they will find out about the assistance when Macu has finished helping them. If a party member is simply indifferent to Macu then Macu will give the party another chance, in a different situation, if the party is still indifferent then he will leave them alone without interfering with them anymore. If the party is cruel or evil in anyway to Macu then he will punish them is some suitable way that matches their evilness. He will even show himself to them so that they will recognize him and the fact that they were evil/cruel to him.
When you sleep, your soul briefly returns to the place where it was created/goes to when it dies, and seeks nourishment. Everybody's soul is created with a little link (or you could say a greater entity calls it back) to that place so that it can return easily, but upon death, the soul returns via that and annihilates the link as if returns.
Also, as an added thingy, you could say the entity supplying the link, or residue of the links themselves, (whichever) is the source of all arcane power.