Criminal Syndicate Bioron
An armed force organized by the mysterious scientist Doctor Giba intending to take over Japan by means of narrow attacks rather than large-scale destruction. Their theme/weapon is biochemistry.

Doctor Giba
A brown-haired, bearded human-looking leader and founder of Bioron. His real identity is Gibanoid, a bio-monster born by accident from the chemical waste of Doctor Igarashi's National Science Academy Bio Laboratory. As a result, Giba is filled with malice for humans. He assumed his true form in the series finale, using Mayumi as a shield to escape in his ship. He died while fighting Jiban on his ship as it crashed into the mountainside.

Marsha and Karsha
The first bio-lifeforms created by Kiba, his secretaries and intermediaries between him and his Bionoid agents. They can transform into small spiders (for spying on people), and assume their inhuman "Battle" forms (Battle Marsha and Battle Karsha), armed with energy whips. They were killed in the series finale by Doctor Giba for failing to kill Jiban.

Bubi and Muku
The cute and not so-cute creatures living in Bioron's base. Muku was one of Jiban's foes in early chapters, in giant size, but only as a distraction. The 4 critters had a tendency to annoy Marsha and Karsha with their Commentary of what the 2 recently did during that episode. Sometimes just showing up once to be used as target practice by the Bionoids demonstrating their powers. The 4 became friends with Mayumi when she told them about a Mothers love and she tried to defend them from Marsha and Karsha who attacked the critters for saving Mayumi's life by Defusing the bomb in Fake Momnoid. They hung out with Mayumi in the finale.

Madogarbo
A Jiban Cyborg Killer created by Doctor Giba as a counter to Jiban. Using power from Queen Cosmos, she and Rhinonoid are able to kill Jiban in Episode 34, but he is resurrected as Perfect Jiban. She later assumes his total appearance to attack him by having his Reson, Spylas and Vaican attack Jiban making them believe Jiban was Madogarbo. She even got as far as damaging Jiban so badly that he went Blind but Mayumi's Despair at seeing her brother about to be killed caused what energy of Queen Cosmos was left to gather and blast Fake Jiban turning her back into regular Madogarbo she was then killed by jiban.

Queen Cosmos
A lunar life form resembling a human woman (but actually a floating rock like starfish with a long tail) intent on conquering Earth to establish an all-woman empire. She appeared in episode 28 but did not reveal her name till episode 34. In her own words, she is made of space garbage and came from a place that was cold and ugly lacking anything beautiful. Thus her obsession with having everything beautiful and being called beautiful herself. She is more powerful than the other Biorons (except Doctor Giba himself), she allies with them to destroy Jiban. Her Jewelry turns into Parasite creatures: Earring into a Skull patterned Ladybug that would infuse into Jiban distorting his Circuitry and her Brooch would turn into a spider creature blasting Jiban with Tiny powerful balls of light. Her bracelet was able to transform into a Snake creature wrapping around ones neck to control their mind. In Episode 46, she was defeated by Jiban.

Golem Cosmos
A off-shoot of Queen Cosmos herself, this entity was created to be her champion from a piece of herself. The creature was extremely powerful, armed with a crescent sword and shield, she very nearly defeated jiban. Until he grabbed her sword wrist with Powerbreaker, twisting her wrist and impaling her with Needricker. She then turned back into her clay statue state and disolved.Weapons: A Long silvery sword, shield, energy blasts from sword and laser blasts from eyes.

Masques
The mass-produced grunt human-like life forms armed with knives, guns, machine guns and bazooka. They can disguise themselves as humans and regenerate lost limbs. A determined human (usually Yoko and sometimes Kiyoshiro) can take them out by shooting them in the head or chest or by physically choking them out.

Gavan Dynamic
This is Gavan's finishing move which he performs to destroy the monster by slicing him in two with his powerful laser blade.
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