Set in the fictional American town of Charterville, three "typical average kids", Drew (Wesley Barker), Jo (Shannon Chandler/Brittany Konarzewski), and Roland (Herbie Baez), enter the supposedly haunted Hillhurst Mansion after accepting a dare from rich-kid snobs Van and Trip. The house is revealed to be the home of real monsters when the kids accidentally bump a pipe organ, releasing a phantasm named Flabber (Billy Forester). He proves to be friendly, and in return for releasing him, offers to grant them one wish. They wish to become their favorite comic book heroes, the Big Bad Beetleborgs. However, this also brings the Beetleborgs' sworn enemies to life: the Magnavores, led by the evil Vexor, who would summon monsters from the comic books to battle the Beetleborgs. Roland's mom and dad run the comic book shop along with his grandmother Nano. In a 6-parter, Vexor created his own Beetleborg, Shadowborg, which was a match for the Beetleborgs and briefly took their powers. They had to call a temporary Beetleborg (White Blaster Beetleborg) Josh, and after Shadowborg was destroyed, Josh lost his powers. The Beetleborgs would meet the Beetleborgs' comic creator, Art Fortunes during this six part story in order for him to create the White Blaster Beetleborg and the Mega Blue Beetleborg. In the second to last episode of the first season, the Magnavores steal a picture of a new villain named Nukus from Art Fortunes' office. They bring him to life to enlist his help in destroying the Beetleborgs. Nukus assists them by planning devastating attacks on the city and creating Borgslayer, a hybrid of all the Magnavore monsters. Unbeknownst to the Magnavores, Nukus was actually plotting to get rid of them. Nukus tells Van and Trip (who were fleeing Charterville during Borgslayer's attack to their father's country estate) how to defeat Borgslayer, and orders them to take the information to the Beetleborgs. They succeed in destroying Borgslayer, causing the Magnavores to be swept back into the comics. In the last episode of the first season (and the first episode of the second season), Nukus challenged the kids to one last battle and despite Art's warning that he is too powerful, they face him anyway. Nukus quickly wipes them out, and destroys their armor, weapons, and powers, seemingly victorius
- Main article: Beetleborgs Metallix
- Andrew "Drew" McCormick - The Blue Stinger Beetleborg, and later the Chromium Gold Beetleborg in the second season, is the leader of the Beetleborgs. And is the main lead protagonist of the series. He was granted the ability of telekinesis by Flabber, which he activated by pointing at an object and nodding his head. Drew received an upgrade, Mega Blue Beetleborg, after he used the energy axis that powered Shadowborg on his original armor. After Roboborg arrived, Drew received a new upgrade, Mega Spectra Chromium Gold Beetleborg, after Nukus and Vilor went Mega themselves. His armor was modeled after a Japanese rhinoceros beetle. He was portrayed by Wesley Barker.
- Roland Williams - The Green Hunter Beetleborg, and later the Titanium Silver Beetleborg in the second season, his family owns a local comic book shop named Zoom Comics, where he, Jo, and Drew usually hang out. He was granted the ability of super speed by Flabber, which he activated by snapping his fingers. After Roboborg arrived, Roland received an upgrade, Mega Spectra Titanium Silver Beetleborg, after Nukus and Vilor went Mega themselves. His armor was modeled after a stag beetle. He was portrayed by Herbie Baez.
- Josephine "Jo" McCormick - The Red Striker Beetleborg, and later the Platinum Purple Beetleborg in the second season, Drew's little sister, she was granted the ability of super strength by Flabber, which she activated by cracking her knuckles. After Roboborg arrived, Jo received an upgrade, Mega Spectra Platinum Purple Beetleborg, after Nukus and Vilor went Mega themselves. Her Red Striker armor was modeled after a flower beetle, and her Platinum Purple armor after a ladybug. She was originally portrayed by Shannon Chandler, and later Brittany Konarzewski. Jo is often shown wearing a baseball cap backwards.
- Josh Baldwin - The White Blaster Beetleborg, granted the ability of invisibility by Flabber, which he activated by dusting his hands. He was on the team for a very short period of time. The White Blaster Beetleborg was created after Shadowborg, an evil clone of the Beetleborgs, stole their powers. He succeeded in getting their powers back. However, it was soon discovered that the White Blaster and Shadowborg were linked in a fashion of yin and yang (mainly because the White Blaster powers were created solely to battle Shadowborg), meaning if one was destroyed, the other would lose his power forever (it could be assumed that it didn't really bother him, seeing as he felt he couldn't handle a superhero life). Josh and Drew were rivals to fall for Heather. Josh accompanied the Beetleborgs in the final battle against Shadowborg, where he transformed for the final time. Shadowborg was defeated by Drew (in his Mega Blue Beetleborg form), and due to the link, Josh lost his powers, at which point, Josh returned to a normal life. Although he said that if the others ever needed him again, he'd be there, but this was the last we saw of him. It was slightly hinted that Jo had a crush on him. His armor was modeled after a hercules beetle. He was portrayed by Warren Berkow.
- Karato (voiced by Richard Epcar) and Silver Ray: Two other comic book superheroes that the kids are fans of. When the Magnavores released an army of monsters while trying to kidnap Art Fortunes from a comic book convention, the Beetleborgs were afraid of being unable to beat them all by themselves. Flabber agreed to use his magic on just that one occasion to summon other superheroes from the comics to help.
- Astralborgs: Four heroes of the Lost Comic.
- Dragonborg (voiced by Doug Stone impersonating Sean Connery): Modeled after a dragonfly, leader of the Astralborgs.
- Fireborg (voiced by Gene Holliday): Modeled after a firefly.
- Lightingborg (voiced by Richard Epcar): Modeled after a cicada.
- Ladyborg (voiced by Barbara Goodson): Modeled after a butterfly.
- Hillhurst Inhabitants
- Flabber (Billy Forester): As described above, Flabber is a phantasm (phasm) who was trapped inside a pipe organ, and was freed by the kids. Out of gratitude he granted their wish to become their comic book heroes, the Big Bad Beetleborgs. This event also unintentionally released the Magnavores. Flabber was released by playing 3 notes (And later revealed that playing those same 3 notes, then playing them in reverse would again trap him inside the organ). He acts as an advisor and best friend, he offers needed magic to the kids when fighting the Magnavores, and later the Crustaceans. Although his magic doesn't always work the way he would hope for it to. He is the head of the Hillhurst Mansion and is usually the one to keep the house monsters in check. The producers of the show said that he was based on Elvis Presley.
- Mums (played by Blake Torney, voiced first by Michael Sorich and later by Torney): Mums is a 5,000 year-old Egyptian mummy, but he can unwrap his bandages to reveal a "Grim Reaper"-like form under his bandages. He has 703 brothers and sisters. In one episode, two archaeologists came to return Mums to the crypt in which they found him in order to get rid of a curse placed on them.
- Frankenbeans (David Fletcher): Called "Frankie" for short, he is a strange, lumbering Frankenstein's monster-type monster. He was once kidnapped by the Magnavores, and held by ransom in exchange for the Beetleborgs' Beetle Bonders. He allows Wolfie to stay in a dog house kept in his room. He has little ability to speak, often roaring or saying toddler-like sentences. Dr. Baron von Frankenbeans, his creator, showed up in a few episodes, a mad scientist who treated the monsters like servants. Whenever he announced his full name, he would be spotlighted by moonlight as lightning would flash and a wolf would howl outside (even if it was daylight).
- Count Fangula (Joe Hackett): Loosely modeled after Count Dracula, Count Fangula is a vampire (albeit one of questionable aptitude in the Dark Arts). He seems to be the only one to understand what Wolfie is ever saying. He once succeeded into getting two victimes in Van and Trip, temporarily turning them into vampires that were turned back to normal by kisses from Jo. If his victims quota is too low, a high ranking vampire will come to evaluate him.
- The Pipettes (Traci Bellusci): A multicolor spirit-like trio of ladies who live in the pipe organ. They act as Flabber's back-up singers. They stop appearing midway through the first series.
- Ghoulum (voiced by Dan Letlow for one episode only): A living stone statue type monster that resides in Hillhurst Mansion who often had little to say or do other than what statues do best, stand in place. While not the most active monster of Hillhurst Mansion on rare occasions he would join in on the other monsters' mischief. In one episode, he was accidentally exposed to a 'Bad Potion' turning him evil and causing him to grow into a giant under Noxic's control.
- Wolfgang "Wolfie" Smith (Frank Tahoe, voiced by Michael Sorich, later Scott Page-Pagter): Wolfie is a werewolf and is treated more like a family dog than a monster at Hillhurst. His voice sounds similar to Astro and Scooby-Doo. Only Fangula can translate what Wolfie is saying most of the time. Probably the bravest and most cunning of the Hillhurst Monsters because he's the only one of the group who tangled with the bad guys at least once.
- Little Ghoul (Lina Godouse): A Jawa-like ghoul who was the latest addition to the Hillhurst group in season two. She lives in the basement and rarely comes out. A niece of the Grim Reaper, she is a grim reaper-in-training who loves collecting. She also has a short temper, which scares the other monsters even more than her true appearance under her hood. She has little to no respect for anyone; she does, however, have a great deal of respect for the Astralborgs. In one episode, she possessed a head that originally belonged to the Headless Horseman.
- Arthur "Art" Fortunes (Rigg Kennedy): Creator of the Beetleborgs comics, who shows up time and time again with new ways to help the kids. He often collaberates with Flabber's magic to bring new arsenal to the kids.
- "Nano" Williams (Vivian Smallwood): Roland's grandmother, Aaron's mother, and Abbie's mother-in-law, Nano is one hip granny and a trained martial artist. When she's not running Zoom Comics, or practicing her moves, she's often seen riding her motorcycle. Nano often helps out the kids when they're in a jam. If nothing else, she enjoys teasing her son Aaron.
- Aaron Williams (Kim Delgado): Roland's father. He ran Zoom Comics full time and is often embarrassed by his mother's antics. Aaron was soon called away on business, leaving the shop in the hands of his wife.
- Abbie Williams (Channe Nolan): Roland's mother. She primarily works as a real estate agent. When her husband, Aaron, gone on business, she assumed running Zoom Comics. She and her mother in-law don't see eye to eye but she didn't really know how to run a comic book shop. With a little help from Flabber's magic, Abbie's heart opened up and rekindled fond childhood memories of a comic she once loved reading. She ran the shop for the remainder of the series.
- Heather (Elizabeth Z. Lund): Drew's crush. No matter what, Drew could never tell Heather what he really felt. She would sometimes help out at the comic shop, and she also enjoyed reading them. During the Shadowborg saga, she developed a crush on Josh.
- Trip & Van (Todd Hurst & Patrick Seaborn): These brothers constantly pestered the kids daily lives by flaunting their wealth and self-acclaimed superiority. Trip was the smarter of the two, whereas Van was a bit slow. They often came up with get-rich-quick schemes, ways to humiliate the kids, or simply to cause trouble; often dragging their unwitting chauffeur, Dudley, into their schemes. They were the one's who dared Jo, Roland, and Drew to enter Hillhurst, which led to them becoming Beetleborgs. During the Borgslayer fiasco they left town to go live at their father's country estate, only to be mentioned once in season 2 (but not before Nukus forced them to return to town to tell the Beetleborgs how to defeat Borgslayer in order to get rid of the Magnavores).
- Magnavores (2-53): The first set of villains the Beetleborgs faced, who originated from the Beetleborgs Comic, but were released due to Flabber granting the kids' wish which unintentionally released them..
- Vexor (first played by Rick Tane and later by Kisu; voiced by Joey Pal): The leader of the Magnavores. He loses patience with his Magnavores' incompetence and does not appear in every episode. He appeared to have been destroyed by the combined efforts of all three Beetleborgs stabbing their Beetle Battlers into his body and pulling him to the ground, after Drew battled with and destroyed Shadowborg, but quickly revived himself, sprouting a new body and face and even managed to grow giant. In his following appearance, he somehow switched back to his old self/appearance.
- Typhus (played by Kyle Jordan and voiced by Dave "Foots" Footman): A Chimera/composite-like humanoid monster, prefers brawn over brain and his whale-like flattop is an extra mouth with which he eats food or other objects. In battle, he sometimes wields a sword-like weapon that latches to his arm or his mouth. This weapon can also blast lasers when latched to his extra mouth. Temporarily turned into Mega Typhus.
- Noxic (played by Lee Whey and voiced by David Umansky): An android with coils for hair who wears a white labcoat-like jacket. Can control machinery and other objects by removing his head and attaching it to them. In a dream of his, he took control of a bulldozer with his head and tried to destroy the Beetleborgs. He later used this same technique to take control of Ghoulum, went he went bad from the comic book's formula. He has an unseen wicked friend, from the comic books as well, named Dr. Cackle, who created the evil formula. Prefers to eat donuts all day long instead of doing Vexor's bidding. He has an older brother named Super Noxic, though technically Noxic was created first. In battle, he sometimes wields an umbrella-like weapon.
- Jara (played by Balinda English in U.S. Footage, and voiced by Rajia Baroudi): Female humanoid clad in red attire and a white mask. She speaks with a Russian accent. Despite her face being remade 3-dimensional, she cannot consume food or smile in the real world because the mouth on her mask could never open (she emphasizes this by saying that she has no mouth). She was bitten by Wolfgang in one episode and became a werewolf and enamored with Wolfgang, but by the end of the episode was returned to her normal form by a rubber arrow, shot by Flabber, which contained antidote and retained none of her affection for Wolfgang. In battle, she sometimes wields a whip that when cracked releases destructive energy.
- Shadowborg (voiced by Bob Papenbrook) (26-31): Black evil Beetleborg created by Vexor from ionic DNA and insectite material stolen from the Blue Stinger Beetleborg. Not only is Shadowborg created from the basic materials as Blue Stinger, but he is enhanced with some of the powers of the other Beetleborgs. Shadowborg can run faster than the Green Hunter, jump higher than Red Striker, and remain underwater for 51 minutes. Shadowborg's architectural armor is modeled after a longicorn beetle. With his Shadow Claw, Shadowborg can cut through any substance known to the planet. He was finally destroyed by the Blue Stinger Beetleborg in his Mega Blue Form.
- Scabs (3-53): Yellow-black goon squad. Unlike in most Saban adaptations, these grunt soldiers were barely used.
- Magnavore Jet Fighters (3-53): Air-borne, wasp-resembling machine jets. Summoned to attack the Beetleborgs on several occasions.
- 'Crustaceans' (52-88): Villains created by Les Fortunes, the second set of villains the Beetleborgs faced.
- Nukus (Christopher Cho) (52-81): A creation of Les Fortunes, the Triceratops-based Overlord of the 2nd Dimension. Hid away in Art Fortune's vault until the Magnavores took the picture and Vexor brought him to life. Nukus quickly set a plan to dispose the Magnavores and take over as the new villain. He broke Les out of jail to use the artist's skills to create deadly monsters that could be brought to life with the use of his sword. He had an advantage over the Beetleborgs as he destroyed both the paper he came out of and the copy Art Fortunes owned. Nukus also destroyed the Beetleborgs' original armor, weapons, and powers. He later gained a mega form, Mega Nukus (81-88), from touching Les Fortunes' transmographier device which he destroyed soon after to ensure no one else received an upgrade from it.
- Horribelle (Claudine Barros) (54-88): Second-in-command of the Crustaceans, an insect-based sword-toting fighter and Nukus' right-hand woman. Like Nukus, she can summon a face-mask in battle. She also wields two swords that resemble mantis arms. She once rebelled against the Crustaceans by having Les Fortunes create the Astral Axe, so she could control its powers out of a scorn for not receiving a mega form like the main male villains.
- Vilor (played by Kyle Jordan and voiced by Dave "Foots" Footman) (54-88): Third in command of the Crustaceans, a fish-based, trident-toting fighter. He briefly gains a second form, Super Vilor (76), when the Mantrons arrived, and later a brief mega form, Mega Vilor (81), after touching Les Fortunes' transmographier device prior to its destruction, though he somehow reverted back to his normal state.
- Lester "Les" Fortunes (Marshal Hilton) (54-88): The black sheep in the Fortunes family, Art's older brother. He was in jail when Nukus recruited him to his cause. Despite creating all the Crustacean monsters and their arsenal, Les never gets any respect or credit for it. At the end of the series, he goes back to jail for some peace and quiet.
- Mantrons (75-82): Evil counterparts of the Astralborgs. Created by Les Fortunes as a child to rival Art Fortunes' Astralborgs in their only collaboration, the Lost Comic. They were there to aid Nukus in his plans to get Roboborg, who ultimately made it to the good hands of the Beetleborgs. In 'Roboborg' (part 8 of the Lost Comic saga), the Mantrons were finally sent back to the Lost Comic for good by the combined attacks of the Beetleborgs, Astralborgs and Roboborg.
- Dregs (55-88): Assorted monsters used as foot soldiers. Dregs came in two groups. One group was based on land animals and wore brown slacks and black boots (Spider Dreg, Stego Dreg). The other based on sea creatures and wore blue spandex pants and white boots (Fish Dreg, Jellyfish Dreg, Squid Dreg). Each group consisted of five different types of Dregs.
- Worm Tanks (55-88): Giant worm like vehicles summoned to attack the Beetleborgs on several occasions.
- Crustacean Jet Fighters (56-88): Air-borne machines based on the design of the Worm Tank summoned to attack the Beetleborgs on several occasions.