Manifestation

Manifestations are the most blatant proof of the supernatural - scars left behind where a Power gouged out a piece of reality and remade it in its own image. Fortunately, successful manifestations are quite rare - it takes a concerted effort by a Power and its most dedicated followers to even make the attempt, and if the attempt is disrupted, it will be decades before a serious attempt can be made again.
Manifestations can take place in a variety of scales. The greatest of these, sometimes termed a "Full Manifestation" or more generally the Apocalypse, would be global in scope, effecting all of humanity. Given the dire implications that such an event would have, it is clear that this has never been successfully achieved...or if it has, that the results are decidedly less cataclysmic than is generally believed. Attempts at a more modest scale, such as claiming a town or city district, or even just a building, are the most common. Such efforts are easier to conceal, more defensible and less costly if they do fail.
What those lost in a Manifestation suffer is rarely known in any detail, as escapees are...not common. From the handful of descriptions gathered throughout history, it is clear that the environment within a Manifestation is an intensification of what a Power represents. For example, one account of a Manifestation of the Hunter dooms its victims to hunt each other, gripped by a preturnatural bloodlust, and kill until only one remains standing...only for each person to rise again, healed of their physical wounds and once again filled with the need to hunt and kill each other. This leads to the prevailing theory that a Manifestation is, effectively, just a renewable food source for the Powers, and possibly their most monstrous agents, as we know the Powers seem to feed on emotions, particularly hope and fear.
However, this leads to competition between the Powers. Many of their aspects are fundamentally opposed (indeed, many ancient societies saw in their actions the wars between two or more factions of gods), and since Manifestations appear to be permanent, there is necessarily a finite amount of opportunities for Manifestation. This means every Power has a vested interest in preventing every other Power from Manifesting. Guild Hunters have attempted to disrupt a Manifestation only to find themselves in a grand melee as agents of several of the Powers unleashed their version of hell indiscriminately in their own attempts to disrupt the proceeding. Primarily as a result of this, there are only a dozen or so Manifestations known to the Guild, the largest of which is less than two miles across.