Demons have similar class and license restrictions, and are accompanied by familiars instead of angels. A seal exists between the demon world and Earth, named the Gate to the Netherworld. It was "created by the gods and can only be broken by an instrument of the gods." As such, demons require a catalyst to manifest on Earth. The demons possess a system similar to Yggdrasil, named Nidhogg. Both demons and goddesses possess the power to seal beings away. The demons also operate in a fashion similar to goddesses by creating contracts with humans and offering them wishes, but often at a price.