Avatar

An avatar is the only method the gods, devils, or demons can enter the Shadow Realms after the creation of Heaven's Gate. An avatar is created by forming a body from spiritual power and giving it life with the power within them (see Spark of Creation or Un-Life).

Unlike the beings that created them these avatars have a relatively short time before the expire. The spiritual bodies fashioned for them consume the power in order to shield the Shadow Realms from the power contained within. When there is not enough spiritual power left the power within will cease to exist. The more power that the avatar must draw upon the faster it will consume its spiritual body.

Main Article: The Fallen

The only other way for an outer being to enter the Shadow Realms is to give up their own power (Spark of Creation or Un-life) before entering. Once this happens the being can never again regain that power and become one of the Fallen, in essence they become a very powerful avatar but can never leave the Shadow Realms.