The world is a thin shell over an underlying sea of chaos. Beneath the veil of reality is the roiling primal energy of creation, the endless potential of the unformed. In the time before history, Creation was raised from this ocean of madness, trapping its energies into the fixity of shape and time, cause and effect. This infinitude is the Wyld.
Just as the Wyld is beneath the world, it is also within it. Wherever the minds and dreams of living things have been stripped away, the Wyld seeps in, burgeoning with twisting miracles. The ravages of Fair Folk armies impregnate it with seeds of impossibility. Where sentient life flourishes, reality is strong, but in places where dreamers are hollowed and their souls eaten away, Creation falls into chaos.
Within and beneath, the Wyld is also outside, surrounding the world. In the First Age, Creation was much larger, its borders well-guarded; but in the wake of the Great Contagion, the children of the Wyld launched a great crusade against the world, and much of Creation’s hinterlands fell back into the chaos from which they were drawn. Today the borders of the world are a tattered and hazy interstitial realm of miracles and nightmares, where the tides of the Wyld grind away at the shores of the real.
Worse, the denizens of the Wyld have long regarded Creation with hungry eyes, gleaming with equally deadly love and hate. The Wyld is home to innumerable prodigies, many of which could only generously be called life—vast and magnificent beasts which could only be of singular nature; swarming horde- and hive-things; mad creators who bring forth land and song and sorrow with the beating of drums or the working of hands; countless hungry fangs, thirsting for passion and meaning; things which all of the above would name as monsters. The foremost among these beings, most commonly known as the Fair Folk, have mounted many invasions of Creation throughout the ages, and marked the bordermarches of the world with the shifting, dreamlike energies of the Wyld.
To live in these tainted lands is to risk becoming something other than human. Savage tribes carve bone and iron talismans in the hopes that they will offer some protection against the touch of chaos, and beseech whatever divinities will listen to keep them safe from the hungers of the Fair Folk. At the rim of the world, where reality is at its weakest, these measures often prove inadequate, and many tribes have been transformed into Wyld-twisted mutants.