Whilst investigating a sudden mass swarming of insects, researcher Takuya Kai of the Earth Academia meets the mystical Insect Elder Guru. He tells him that the insects sense the invasion of the extra-dimensional Jamahl Empire, and are preparing to fight them. With Guru's help, Takuya and his mentor Professor Mukai develop three Power Armor suits infused with the power of beetles. One suit is entrusted to Takuya, the other two to Daisaku Katagiri and Rei Hayama. They become the B-Fighters, who regularly oppose the schemes of Jamahl and its three generals.
- Takuya Kai/ Blue Beet: The Hero; an insect researcher from Earth Academia who is the first to learn of Jamahl's evil schemes.
- Daisaku Katagiri/ G-Stag: Big Lancer; a tree doctor who claims to hear the voices of trees.
- Rei Hayama/ Reddle: Fragilistic Chick; an animal instructor. She left to do animal research in South America and was replaced by Mai Takatori.
- Emperor Gaohm: The Big Bad
- Jera: The Dark Chick
- Schwartz: The robotic Evil Genius
- General Gigaro: The Brute
- Sorceress Jagul: Another Evil Genius; the Sixth Ranger responsible for Shadow's creation. Actually killed off shortly after, but comes back once every other villain is dead.
- Shadow/ Black Beet: Takuya's Evil Twin.
- All Your Powers Combined: Jagul absorbs the powers of various monsters to assume her One-Winged Angel form.
- Bad Boss: Gaohm's methods for completing the Jamahl Hole end up costing Gigaro and Schwartz their lives. He also kills Jera for seeing his true form.
- Berserk Button: Do NOT attempt to cut down a tree when Daisaku is nearby.
- By the Power of Grayskull: "Juukou!" 
- Calling Your Attacks
- Crossover: The final episodes featured Blue Swat and Janperson aiding our heroes.
- Drop the Hammer: The motif of episode three's monster.
- Everything's Better with Spinning: The B-Fighters' weapons all spin when activated.
- Green Aesop: Although it decreases over time, the show often focused on damage being done to the environment, with most of the B-Fighter's weapons and equipment being infused with insect powers.
- ~Hey, It's That Guy!~: Shadow is Kirin Ranger, and his real-life twin is Takuya. Daisaku is Mega Silver.
- Humongous Mecha: The Beet Machines, a trio of beetle-themed vehicles, and Mega Heracles, a gigantic mechanical Hercules beetle.
- Japanese Beetle Brothers: Blue Beet and G-Stag are a Type A.
- Making Use of the Twin: Takuya and Shadow, due to being identical twins.
- Mid-Season Upgrade: Blue Beet's Beet Ingram gun, which allows him to transform into Super Blue Beet.
- Mind Screw: The Gaohm Zone. The fight scenes which take place in it range from slightly weird to flat-out insane. Some parts (such as one instance where G-Stag ends up getting randomly slashed with switchblades on a busy street) are outright bizarre.
- Mooks: Jahmal's Jamars.
- Out of the Inferno: Pulled by the B-Fighters in episode three, when walking out of a destroyed building.
- Powered Armor: The B-Fighters' Insect Armor.
- Real Life Writes the Plot: Reina Hazuki (Rei) suffered a neck injury during filming, forcing her to leave the show.
- Super Strength: One of the powers given to the B-Fighters by their armor
- Synchronization: Whenever Shadow hurts Takuya, or vice-versa, they each feel the pain.
- Transformation Trinket: Handheld devices called the B-Commanders.
- "Heavy Shell!"