The Neo Empire Gear (新帝国ギア, Shin Teikoku Gia?) was founded and led by the cyborg Doctor Man, from his Neo Grad fortress at the South Pole. The bulk of their forces is composed of five cybernetic monsters known as the Beastnoids, and of generic android soldiers known as the Mecha Clones. Farrah is also assisted by Farrah Cat. Their motto is "For the man!"
- Doctor Man (ドクターマン, Dokutā Man?): The supreme ruler of the Neo Empire. Once human, he was known as Doctor Kageyama Hideo (English version is: Michael O'Hara). He experimented on himself aiming to be the most intelligent being on Earth only to have his body age quickly in the process. To extend his life, he cybernized himself and later apparently became a completely mechanical being. He developed a deep disgust for humanity, and plans to conquer the world with his army of mecha humans. When his assistants were failing, he created the Black Prince in the image of his real son Shūichi. He tried to get Shuichi to join them but failed. He eventually was prepared for any conspiracy against him and later reprogrammed the Big Three and reorganized the empire. With his empire dying, he goes and fights the Biomen with the Mecha Gigan King Megas only to be defeated. He activated the Neo Bomb but he ended up stopping it when his son and the Biomen prodded him eventually resulting to his death.
- Big Three (1-50) - The three android generals who supervise field missions. They can also disguise themselves as humans.
- Mason (メイスン, Meisun?): The leader of the Big Three. Murdered Mika Koizumi, the original Yellow Four with the Bio Killer Gun(which resembles a sniper rifle with a magazine of a tommy gun) while he originally planned to kill Gō Shirō. He once plotted against Doctor Man himself after he found out Doctor Man was a human being. He is armed with a staff which fires energy bolts which was later broken in half by Red One. He later fired an energy bolt to Red One from his chest after his Staff was Broken. Doctor Man apparently puts more importance on him than the other two. He later shares a close relationship with Farrah. He was later rebuilt and armed with Mason Rockets and Mason Machine Gun. He is the frequent rival of Red One. He was eventually killed by Silva. Before dying, he was able to utter his last words "for the man" and eventually exploded.
- Farrah (ファラ, Fara?): The female member of the Big Three, she uses beam weapons and leaves the dirty fighting to Farrah Cat. She often disguises herself as human in her schemes, favoring cunning and deception above brutal force. She used to show resentment towards Mason but later developed a close relationship with him starting with the plot to steal gold bars which Mason designed. Later rebuilt and armed with Farrah Fire Storm and Farrah Kiss (blows an explosive flying kiss). She is rivals with Yellow Four and Pink Five. She died after receiving damage in battle while piloting Balzion.
- Monster (モンスター, Monsutā?): He is as strong as a whale and less than half as smart. He likes to work with the monster Beast King frequently, though he worked with Messerjū and Aquagaiger at one point. He was later upgraded and armed with Black Mace, Iron Paw. Despite being an android, he is revealed to have feelings for Farrah which she resents and Mason considers it disgusting suggesting a love triangle. He was killed while trying to capture Balzion. English version is: Vargo
- Farrah Cat (ファラキャット, Fara Kyatto?): Farrah's android bodyguard who does the dirty work. Dressed in black and purple skins, she is quick, agile and acrobatic. She has claws for weapons and uses twin nunchukus as well. She is Yellow Four's frequent rival and at times Pink Five. Only troop not to receive an upgrade, and the last to be destroyed before Dr. Man. She was killed in the final episode by Yellow Four and Pink Five who blew off her circuits with a full blast.
- Mecha Clones (メカクローン, Mekakurōn?): The robotic foot soldiers of the empire in black with silver heads and red eyes. They can be programmed to pilot Mecha Drones or act as laboratory assistants. Others were designed for special purposes. The only advanced mechaclones were the Black Prince and Miki.