Outsider

An Outsider is any being that is outside of the realm. The three realms are the Divine Realms, Shadow Realms, and infernal Realms. If a creature of the Infernal Realms is inside the Shadow or Divine Realms then they are an outsider. Likewise if a creature of the Shadow Realms is inside the Divine or Infernal Realms. This may be through any means from the physical to simply extending their power and beliefs.

An concept of the realms seek to eject all outsiders. This leaves outsiders more vulnerable that native creatures of their realms. Outsiders can be banished if sufficiently overpowered, they can be bound up in native beliefs. Circles are common among the mortals of the Shadow Realms when dealing with outsiders. This is built upon their beliefs - likewise for wishes, bargains, and the afterlife.