The Secret Society Egos is an extremist religion composed of mad egocentrists who intend to plunge the entire world into chaos.

The mysterious head of the society, entirely draped in black. He creates the Egos Monsters inside the Egos heart, affectionately calling them "My beloved Children," while they revere him as "Father."

He is ultimately slain by the Battle Fever team's Lightning Light Sword Rocketter attack.

The high priest of Egos and Satan Egos' primary proxy. He later mutates into the monstrous Hedder Monster and is slain in this form by Battle Fever's newly developed combined attack, Battle Fever Power.

An Egos American branch officer who traveled to Japan to aid Commander Hedder, utilizing her superhuman strength. She is responsible for a string of brutal assassinations across America.

At one point, she allowed herself to be captured by Battle Fever after attacking and replacing several policemen with disguised Cutmen, successfully stealing one billion yen for Egos. She mistakenly believed she was being taken to the secret Battle Fever Base, but the team outsmarted her and took her to an empty warehouse.

She carries a hand mirror containing a hidden tracker, which she also uses to fire solar beams or physically bludgeon her enemies. She is ultimately killed in a collapsing castle after Satan Egos abandons her; her final words were desperately begging him for help.

The standard foot soldiers of Egos. They are clad in grey and black uniforms and armed with MP40 submachine guns.

Black fighter planes equipped with bat-like wings, used by the society for aerial combat and bombardments.

The "divine children" of Egos, created directly by the heart-like Egos Monster Making Machine. From Episode 5 onward, many of these monsters are accompanied by giant robot "little brothers," mechanical doubles designed to battle the Battle Fever Robo.