In the World of Darkness, the Umbra is a shadow of reality. It is the "wading pool of the universe", so to speak. It overlaps and reflects the world we walk through every day. However, in the Umbra, emotions and meanings are the life's blood of reality. Something which has no emotion to it (a corporate office building) will appear pale and insubstantial, while someplace with emotional connotations to it (a church, a home) will be vibrant and alive. Even moreso, the "nature" of a place is overtly expressed in the Umbra. A lab may look pristine and clean in reality, but in the Umbra, the dark and twisted spirits and horrible stains tell the tale of evil worked in that place some time in the past.

The Umbra also contains the pathways to the rest of reality. The Deep Umbra, High Umbra, The Mid-Realms, and the Low Umbra (or Underworld) can all be reached from here.