This is a fantasy world, not an alternate Earth world.
Flesh and Spirit
Running parallel to the normal world is the realm of magic. However, people cannot tap into the power there while their bodies still tie them to the world of flesh. To wield magic, one must Sacrifice the body.
The Sacrifice ritual imprints a person's essence into the realm of magic, carving out for them a portion of magic that is theirs to control as a spirit. Their imprint fades as the body's vital energy is used up; to continue existing, spirits must gather energy from their flesh counterparts.
Spirits are common enough — and useful enough — that an entire economy exists around them, where flesh pay spirits for their magical word in vital energy. In fact, each of the 12 guilds has a flesh side and a spirit side to their work. Depending on the guild, this collaboration may be cooperative or competitive.
Half-spirits — children of a flesh mother and spirit father — are taboo and all involved, including the child and any who helped hide its existence, are summarily executed. Legend warns of "Masiri the Monster," a tyrannical half-spirit who ruled and terrorized the country long ago; no one wishes to unleash another such too-powerful being on the world.
Myths
People tell of a time before magic was split between spirit and flesh. Animals were all magical — sentient and intelligent. Nature was a magical entity of its own, and much more volatile and independent than it is now.
