Gauntlet

Separating the Earth from the Umbra is a metaphysical "membrane" known as the Gauntlet. Some humans almost manage to get close to the Gauntlet in times of bliss, meditation, or creativity; this state is known as the Periphery.

The Gauntlet is thinner in places such as a haunted graveyard or the wilderness, and thicker in places such as laboratories and shopping malls. The relative strength of the Gauntlet determines the ease with which one can cross it, or "step sideways." The Gauntlet is usually treated as a single phenomenon, when it is actually sort of three Gauntlets in one: one separating Material World from the Astral, one protecting it from the Spirit Wilds, and one blocking access to the Underworld and the horrors that lie within. The latter Gauntlet is also referred to as the Shroud by wraiths, and as the Stormwall by agents of the Orpheus Group.