Demons are evil spirits that are often humanoid in appearance with some inhuman features, such as horns or wings. In many cases, demons are very powerful and mortals may mistake them for gods or angels.
Demons in NOW Comics Vol. 1-25
Demons in the ghost world possess five men working for A.R.M.O.R.(Advanced Radical Military Occult Railroad) and attempt to use their train vehicle to enter the human world. They abduct the Ghostbusters and believe them to be ordinary humans, until Egon reveals the no-ghost emblem on his shoulder and says that he and the others are the Ghostbusters. Shocked by this, the demons then escape from the five men's bodies and fly away to parts unknown.