The Secret Organization G.O.D., short for the Government of Darkness, is the evil organization that X battles against.
G.O.D. General Commander
A mystery man who commands the monsters using various objects with tape recorders which record his commands.
Apollo Geist
The Chief of Security of G.O.D., armed with the Geist Cutter shield and the Apollo Shot shogun, his human appearance wears a white tuxedo with black gloves until he invokes "Apollo Change". Destroyed himself using his Arm Bomb after he was defeated by X's X Finishing Kick.
Episodes 8-14
Revived Apollo Geist
Revived by two doctors of G.O.D. Armed with the Apollo Magnum bayonet on his right hand, the Geist Cutter shield, and the small Geist Cutter shield on his left shoulder. Destroyed by X's X Kick.
Episodes 16-21
King Dark
The leader of G.O.D., he reveals himself after Apollo Geist's destruction, mocking X. Destroyed by a self-destroying function that Dr. Noroi started.
Episodes 21-22, 32, 35 & Movie
Dr. Noroi
After King Dark's defeat, Dr. Noroi is revealed to be the leader of the Government of Darkness. Destroyed in King Dark's destruction after stabbed by X's Ridol Whip.
Episode 35
G.O.D. Warfare Agents
Warriors who serve as foot soldiers for the Government of Darkness. Not only do they carry spears, they also wield pistols and machine guns.
Government of Darkness Rider
A duplicate of Kamen Rider X.
Episode 29
Series:  Kamen Rider X