Source: MtAw core book p317
Living creatures of flesh and blood inhabit our world — beasts and animals, predators and prey, masters and servants. Yet the majority of people remain blissfully unaware of the unseen realms surrounding them. Existing outside human ken, spirits are at work in the world. Some are benevolent inhabitants of our plane of existence. Others interact with our world as visitors, invaders, guardians or even predators. Spirits may take the forms of angels and demons, faeries and monsters, cars and trucks, swords and kitchen utensils, or creatures so fantastic that they bring madness to any who behold them.
Mages are capable of making alliances with them. Through strength of will, mages versed in the Spirit Arcanum can summon, bind and even control these otherworldly entities. Spirits can be capricious, motivated by what seem to their own whims and desires, but which a shaman knows are aspects of their nature. Unlike a human, spirits cannot act outside their natures — they are their natures. Stories about mages who deal with spirits tell of promises made, pacts forged and friendships broken.
Boons, deeds and even acts of sacrifice forge bonds between living mages and ephemeral spirits. A mage walking in the Shadow can encounter entire pantheons of these entities. Some gather together in kinship “courts” or “kingdoms,” presenting entire societies based on the same powerful myth, theme or legend.