Gou Shiro/Red One
- Ace Pilot: Pilot of both Bio Jet 1 and the first Japanese space shuttle.
- Friend to All Living Things: With his Speaks Fluent Animal powers.
- Law of Chromatic Superiority: Shirou can understand animals, but nobody else is shown to have unmorphed powers. He's also the only one to be directly linked to the Dr. Man part of the plot through his father.
- The Leader: Of the Biomen.
- Playing with Fire: Fire Sword
Takasugi Shingo/Green Two
- Blow You Away: Hurricane Sword
- The Lancer: He is the Number Two after all, but he really cements himself in this position once Mika bites it.
- Precision-Guided Boomerang: Green Boomerang
Nanbara Ryuuta/Blue Three
- Delinquent: He used to be a delinquent in his teen years, but was inspired to change his ways. His first encounter with Prince reminded him of those times.
- Punny Name: His Bioman codename is a pun on how the Japanese pronounce "Bruce Lee".
- Shock and Awe: Elec Sword
- The Sneaky Guy: His years of diving have made him very nimble and thus he is very skilled in stealth techniques.
Koizumi Mika/Yellow Four I
- Anti-Hero: Type I.
- Faux Action Girl: In her nine episodes, she doesn't do much fighting.
- Forgotten Fallen Friend: No mention of her is made after her death.
- Shock and Awe: Thunder Sword.
- Taking the Bullet: More like several as she shields her team singlehandedly.
- We Hardly Knew Ye: Only appears unmorphed in the first six episodes.
Yabuki Jun/Yellow Four II
- Action Girl: Very much so, especially since her actress did her own stunts.
- Martial Arts Headband: You don't ever see Jun without wearing one (and it fits her role too). Even one episode had this weaponized by the villains by replacing it with a time bomb!
- Shock and Awe: Thunder Sword
- The Straight and Arrow Path: Is the only one of the Biomen to wield a physical weapon - a bow.
- Why Did It Have to Be Snakes?: Spiders.
Katsuragi Hikaru/Pink Five
- Barrier Warrior: Pink Barrier.
- Laser Blade: Laser Sword.
- Tender Tears: She's the most emotional of the Biomen and tends to cry easily.
- Gender Flip: Even though he's technically a sexless automaton, he addresses himself as a male in the Japanese original. In the English dub however, he was made female.
- Robot Buddy
- Combining Mecha: Composed of two jets (Bio Jet 1 and Bio Jet 2).
- Humongous Mecha
- Mechanical Lifeform: It is shown that Bio Robo has a will of its own when it runs away during Silva's first appearance.
- Big Bad
- Morally Ambiguous Doctorate: That 'Doctor' title certainly doesn't come from medical expertise.
Bio Hunter Silva
- Big Bad: He reappears as one of the main antagonists of Kamen Rider × Super Sentai: Super Hero Taisen.
- Blade Below the Shoulder: Both which can be fired like arrows.
- Catch-Phrase: Hakai! Hakai! Hakai! (Destroy! Destroy! Destroy!)
- The Dreaded: He possesses Anti-Bio Particles that are more powerful than those used to kill the first Yellow Four (Even though he doesn't manage to kill any Biomen with them). Peebo had a very good reason to fear him.