DEMONOLOGY: A Study on Demons By definition, a demon is a spirit: a supernatural force owned, empowered, energized, motivated and controlled by the devil otherwise known as Satan. The sole objective and function of demons is to carry out the whimsical, nefarious, and diabolical atrocities of its owner and master. It is an accepted given that all spirits are non-corporeal, and in order for them to manifest themselves, to appear, or to effectively function, of necessity they must take on, and clothe themselves with some easily recognizable physical form or body, chiefly that of a human.