Shallow Realms are rare Realms on the very surface of the Umbra, right between the Gauntlet and the beginning of the Umbra, originally formed by magic for a specific task. As such, they require a creator, a connection to a Quintessence reservoir, a set list of people who are authorized to enter, and contact to the Material World. Den-Realms, which are used by the Bastet werecats, are a variation of a Shallow Realm.