As leader of the leader of Egos, Satan Egos has been stated as the black curtain behind all troubles and problems that have occurred throughout world history. Everything from natural disasters to assassinations to wars have connection to him, generally through his Egos followers or through his "children" monsters that he creates to cause chaos. Satan Egos is a black-robed man who sits cross-legged on a platform high above all of his followers, including his commanders Commander Hedder and Salomé. His identity remains mysterious and is never unrobed. Satan Egos sits behind a spinning pentagon crystal; this crystal is the main means by which the being speaks and likewise is the means he beams his own energy to create his "children" Egos Monsters with his Monster Making Capsule.

When General Kurama Tetsuzan catches on to Satan Egos' actions, thanks to the murder committed by the Umbrella Monster, he creates Battle Fever and the means for managing with the evil overlord, including the development of Battle Fever Robo as a secret weapon for dealing with Satan Egos' secret "robot" project.