The monsters used by the Crisis Empire are referred to as Strange Demon Soldiers. There are four branches each lead by an Officer.
Strange Demon Supernatural ClanEdit
The Strange Demon Supernatural Clan unit is used by Colonel Maribaron.
Skullma (Episodes 1-2, 45 and Movie ): A Grim-Reaper style monster with a scythe and assisted by two hornless versions of himself, Skullmastars. He played a part in Kotaro's rebirth into Black RX, killed by him while the Skullmastars live on to serve the Crisis Empire on different occasions. Skullma returned in the Kamen Rider Black RX movie to fight Kotaro before he was sucked into a dimensional warp.
Skullmastars (Episodes 1-2, 9, 19, 32, 42 and Movie ):Two hornless versions of Skullma
Bujin (Episode 7 ): A silver armored swordsman with ability to harness the sun's rays and use them a weapon. He could also move through anything that's reflective. His mission was to steal something from Yousuke Morita, an old friend of Kotaro's. After a brief fight with Bujin, Kotaro learns the blueprints are for a laser the Crisis Empire wants to build. To get the blueprints from Kotaro, Bujin uses Yousuke as a hostage and tricks Kotaro into giving him the blueprints. From there, RX battles Bujin until used his Revolcane to destroy him.
Zunojin (Episode 12 & 45 ): An elf-like monster who wielded a blade and could shoot a beam from his forehead crystal. Maribaron used Zunojin to attack Reiko in her dreams, taking control of the girl's subconscious in another plan to target Kotaro's weaknesses. With the aid of a dying Karu, RX uses the Crisis Marine's machine to enter Reiko's dream, giving Reiko back control over her dream before killing Zunojin with his Revolcane after a brief hestitation.
Byakki (Episode 20 ):A green and white-furred shaman with bat wings for ears. It is armed with a skull-headed staff and bananas that can be used as weapons as well as for other purposes. Byakki used his bananas to infiltrate a gold depository to steal the gold. Joe told Kotaro about a weird old man who bought bananas from his banana stand after following him to his house. Shigeru and his friends stumbled onto his house and were captured. When Kotaro arrived and found Shigeru and his friends, the weird old man revealed his true form of Bya Fiend and attacked Kotaro. Byakki threw a banana into Kotaro's chest knocking him out and then kidnapped him. Atop a building, Byakki tried to use a big banana to push the impaled banana further into his chest, until Kotaro used his Robo Rider ability, which caused the banana to break and allowed him to recover. Kotaro transformed into Kamen Rider Black RX. After some banana attacks from Bya Fiend, Kamen Rider Black RX became Bio Rider. While on Mach Jabba, Bio Rider attacked Byakki and used his liquid powers to evade his banana attacks. Bio Rider broke Bya Fiend's staff before destroying him with his Bio Blade.
Ganma (Episode 32 )
Wilki (Episode 35 ):A one-horned bluish imp monster armed with a pitchfork. He can shoot a beam from its horn. Maribaron planted him inside Kotaro to kill him when he was being pursued by the police. This was a plan by Maribaron to hack into the city records and make specific people look like criminals. When Kotaro found out about Wilki while he was in jail, he henshined into Kamen Rider Black RX and escaped from jail. Wilki even poked him while he was escaping on Acrobattler. While in the sewers, Kamen Rider Black RX became Bio Rider and found out what the Crisis Empire was up to. When the next person was arrested, Wilki attacked Kamen Rider Black RX and attempted to deliver the final blow. Kamen Rider Black RX faked his death and was brought to Maribaron. He eventually became BioRider right as Maribaron was about to destroy him. BioRider revealed that his form prevented Wilki from killing him. With all the police computers experiencing a system down, Maribaron retreated and Wilki attacked. BioRider called out his Bio Blade and fought Wilki and the Chaps. BioRider managed to chop off its horn and destroy its pitchfork. BioRider then reverted to Kamen Rider Black RX and brought out his Revolcane to disarm Wilki and destroy him.
Tenku (Episode 38 ):She is a powerful fortune teller and miracle healer that lured people to help build a city for Crisis. She is actually an ape-like beast beneath her human appearance. She was killed by RX's Revolcane.
Hundred-Eyed Hag (Episode 41):She is Maribaron's aunt and a somewhat very powerful witch. She absorbed Kyoko into herself and later Kotaro and Joe. However Kotaro transformed into Biorider and back to RX and defeated her.
Strange Demon RobotEdit
The Strange Demon Robot unit is led by Captain Gatezawn, composed of various androids built by Gatezawn.
Cublican (Episode 2 ):A robot Gatezawn sent after Kotaro. He disguised himself as a human after stealing some of Hayami's clothes. When exposed after his synthetic skin catches fire, Cublican grew a new head after RX knocked his original off. Kamen RX absorbed the sun's rays to recharge before calling for Acrobatter, using the Revolcane to destroy Cublican.
Gungadin (Episode 4 ):A large robot with tank treads instead of legs sent to kill RX before he completed Rideron, Gungadin attacked with his body guns. Unable to defeat Gungadin on his own, RX tricks Gungadin into thinking he destroyed Rideron while the real car gains life. Offered the title of knight if he killed RX, Gungadin went on a killing spree to force the Rider out into the open. With the aid of Rideron, RX managed to defeat the Demon Robot with his Revolcane stabbing him into the head module.
Scryde (Episode 11 ):A robot that was destroyed by Lord Crisis for being too powerful for the Crisis Empire to control. Gatezawn salvages Scryde and revives the monster, sending him to Earth to use discarded items to seal people before having his army attack humans. Though he nearly killed RX, Kotaro escapes with few injuries as he has Rideron and Acrobattler to break Scryde's hold over his garbage army. Once he knocks Scryde's head skin off, RX destroys him with the Revolcane in order to free the humans from within the discarded items.
Deathgaron (Episodes 14-15, Movie):A humanoid insect robot sent after Kotaro while Hitomi was kidnapped by Maribaron. RX uses him to enter the Desert of Death after Maribaron. As a result, Deathgaron is attacked by Triplon before he offers his services to Maribaron in return for redemption. However, Deathgaron is deceived and ends up being sealed up with RX as he kills off a replica of Hitomi placed there. This in turn causes RX to transform into RoboRider, breaking out of the sealed room and using his Voltic Shooter to heavily damage Deathgaron. Before he died from his injuries, Deathgaron revealed that Hitomi is still alive and with Maribaron.
Triplon (Episodes 15-17, Movie):A robot that first appeared in its splintered form: Triplon Unit 1 and the humanoids Triplon Unit 2 and Triplon Unit 3. Triplon is deployed to the Desert of Death to execute Deathgaron for his incompetence before serving as an escort to Maribaron. When Nexticker is destroyed, the Triplon Units capture Shigeru and overwhelm Kotaro and Joe before they are captured. But when RX achieves the form of BioRider, the Triplon Units dock into United Triplonwhich BioRider destroys with his Bio Blade
Nexticker (Episode 16 ):A blue robot sent to attack Kotaro while he was looking for Hitomi. Controlling Joe as a puppet, Nexticker forces him to fight Kotaro when he almost saved Hitomi. After surviving the attack, Kotaro is ambushed by Joe while on his to the Valley, fighting him as RX before disabling the robot's mind control abilities. Assuming the form of RoboRider, RX converts Acrobatter to Roboizer and overwhelms Nexticker before blasting him with the Voltic Shooter.
Croyzel (Episode 19):A robot that can manipulate heat.
Metaheavy (Episodes 30 & 45 ):A fire-elemental robot. He can manipulate fire. When the Crisis Empire was still hording water, people continued to get them from Maribaron's performing troops. After a brief battle with Maribaron, Gatenzawn, and Gedorian, Kamen Rider Black RX located where the water was being withheld and fought Metaheavy who pulled Kamen Rider Black RX into its fiery location in the factory, where it had the advantage. RX became Robo Rider and managed to knock Metaheavy out of the room. After a few shots on Metaheavy with his Vortech Shooter, Robo Rider reverted to RX and destroyed Metaheavy with the Revolcane, then used the Revolcane to destroy the controls that were withholding the water, thus returning the water to the city. Metaheavy was later revived by Maribaron as part of the Spirit World Kaijin Army.
Elgitron (Episodes 31 & 45 ):An electrical robot. Elgitron was later revived by Maribaron as part of the Spirit World Kaijin Army
Schraigin (Episode 34 ):An Asura-like robot. He wields a spear, two swords, a sickle and a pitchfork in battle. He can also spew acidic foam from his hands. Disguised as a headmaster, he helped General Dasmander (disguised as a female worker) and Gatenzone manipulate children with ESP into causing the country to split from the continent. Kotaro encountered Schraigin first, and henshined into Kamen Rider Black RX to fight him. When Kotaro found where the other ESP children were, he was discovered by Dasmander, Gatenzawn, and Schraigin. Schraigin fought Kotaro before shedding his disguise. Kotaro then transformed into Robo Rider and fought the Chaps and Schraigin. After the machine that the ESP children were attached to was destroyed, Dasmander and Gatenzawn fled as Robo Rider engaged Schraigin outside. Robo Rider reverted to Kamen Rider Black RX and used the RX Kick on him. He then called out his Revolcane and disarmed Schraigin before using the Revolcane to destroy him.
Spingrey (Episode 39 ):A robotic monster resembling an automobile. He was used to capture children and use the Strange Demon gun computer to transform them into killer machines to be used to kill Black RX. He was destroyed by RX's Revolcane.
Helgadem (Episode 43 ):A silver humanoid robot. He can shoot his fists out like missiles. He was commanded by Gatenzawn and battled alongside him.
Strange Demon Beast-ManEdit
This is the unit led by Naval Commander Bosgan, mostly consisting of mutant creatures.
Gynagiskhan (Episode 3 & Movie):An insectoid-like horseman whose helmet has two long horns. He wields a glaive in battle, can manipulate winds, and he can shoot a beam from his hand. He captured Shigeru and his friends when they were eavesdropping and sent Kotaro and Reiko into a planet with insectoid-like people which the Crisis Empire enslaved with their factories built there. In the first battle, Kotaro was able to escape with Shigeru and his friends when the musical item he had on him proved to be painful to Harmful Giskan's hearing. Later, he killed the rebel leader. After transforming, Kamen Rider Black RX and Harmful Giskan fought once the sun rose. Reiko's musical necklace disrupted Harmful Giskan enough for Kamen Rider Black RX to bring out his Revolcane. Once Harmful Giskan was destroyed by it, Kotaro, Reiko, Shigeru and his friends were back on Earth. He returned in the Kamen Rider Black RX movie to assist Death Gron, United Triplon, and Flying Squirrel Beast into attacking the Kamen Riders only to be destroyed by a team Rider Kick.
Gynagamoth (Episode 5):A three-eyed green moth monster whose butterflies could turn humans into insects. He can also shoot laser from its eye and use its tongue to wrap. When Reiko's photography club and Shigeru and his friends entered a cave, they were attacked by Harmful Moth and ended up infected by his butterflies. When Reiko contacted Kotaro, his helicopter was attacked by Harmful Moth's butterflies which led to Kotaro transforming into Kamen Rider Black and fighting Harmful Moth. During the fight, Kamen Rider Black RX called for Ridron who tackled Harmful Moth and took Kamen Rider Black RX to the cave. When entering a cave, Harmful Moth attacked again. Kamen Rider Black RX chopped off Harmful Moth's tongue, but Harmful Moth overwhelmed him. Ridron tackled Harmful Moth before he was destroyed by RX's Revolcane and its hatchlings are destroyed upon its destruction.
Gynamite (Episode 8):A black-haired crab-like monster with a strong-clawed right arm. He also has a toxic breath. He is commanded by Bosgan whom accompanied Harmful Might in the first battle when it came to obtaining a young scientific prodigy. Kamen Rider Black RX fought both of them and eventually called upon Acrobatter. Harmful Might later attacked an amusement park when his disguised himself as the girl's father. Kamen Rider Black RX chopped off Harmful Might's claw where it used its toxic breath on him. Harmful Might tried again to take the girl who used her psychic abilities on him. Kamen Rider Black RX used his RX Kick on Harmful Might before he was destroyed by RX's Revolcane.
Gynabalas (Episode 23):A man-beast type monster with long horns and blue black and white spot over his body who commanded by Bosgan. Besides attacking with his horns, he also wields a sword in battle. Bosgan has invented a machine that turns people into humanoid animals (mostly pigs). When Harmful Brass was sent to obtain a kid who was turned into a humanoid gorilla, he ended up in conflicted with Kotaro who became Kamen Rider Black RX until the kid returned and attacked Harmful Brass. Joe disguised himself as a humanoid pig version of Kotaro to let Bosgan, Harmful Brass, and the Chaps capture him. When Kamen Rider Black RX arrived, Joe sheded his disguise and Kamen Rider Black RX fought Harmful Brass which destroyed the machine that turned people into animals and restored the people back to normal. In the factory,Kamen Rider Black RX with Harmful Brass.They fight till out the factory .When Harmful Brass managed to hit Kamen Rider using his sword , Kamen Rider called out his Revolcane to disarm Harmful Brass .When Harmful Brass 's sword was hit off by Kamen Rider 's Revolcane,Kamen Rider use his sword to slash into Harmful Brass's stomach .This make him seriously injured and was destroyed after Kamen Rider pulled out his Revolcane
Gynakamakil (Episode 25):A black-haired lizard/mantis monster. He can detach the blades on its back to throw them and use them as weapons. He is commanded by Bosgan who accompanied him to attack Kotaro where Harmful Mantis Gill manipulated aluminum cans. In the second time, Joe disguised himself as a bride to lure out Harmful Mantis Gill. While Kotaro and Joe were fighting Harmful Mantis Gill, Bosgan used his new sword on the car that Reiko was hiding in and made off with her. When Kamen Rider Black RX caught up to where Bosgan and the Chaps had the other brides, he ended up fighting Bosgan and Harmfull Mantis Gill. Kamen Rider Black RX became Robo Rider where Bosgan's sword could not penetrate him which ended up destroyed by Robo Rider followed by an attack on Harmful Mantis Gill. Robo Rider reverted to Kamen Rider Black RX and destroyed Harmful Mantis Gill with his Revolcane.
Gynagingam (Episode 25-26):A turtle monster. He can bite, launch his head and neck out to constrict, and shoot sparks from his mouth. He is commanded by Bosgan. Harmful Gingamu caused Reiko to be hospitalized and had Utako give a message to Kotaro where to meet him. When Kotaro arrived at the designated location, Harmful Gingamu attacked. Kotaro henshined into Kamen Rider Black RX and fought Harmful Gingamu until Bosgan arrived with his new sword that can penetrate his Robo Rider form when Kamen Rider Black RX became Robo Rider and ended up reverting to Kamen Rider Black RX after some blows from Bosgan's sword. Kamen Rider Black RX called Acrobattler and retreated. When Shigeru and Hitomi end up captured by Bosgan, Harmful Gingamu, and the Chaps, a weakened Kotaro fought Bosgan and Harmful Gingamu while Joe freed Shigeru and Hitomi. After Joe was wounded by Bosgan, Kotaro transformed in Bio Rider and fought them. Bio Rider was caught by Harmful Gingamu and turned into water to escape and evade Bosgan's sword. After being disarmed, Bosgan retreated. Harmful Gingamu was beheaded by Bio Rider who reverted to Kamen Rider Black RX and destroyed Harmful Gingamu with the Revolcane.
Gynaninpo (Episode 37):A primate monster that leads the Devil Beastman Ninja Corps. Harmful Nimp wields an extending staff in battle which he can shoot beams from it. He can also assume the form of anyone. The Devil Beastman Ninja Corps attacked a mountain village and captured its inhabitants. He and the Devil Beastman Ninja Corps attacked Kotaro and Reika when they were in the woods only to be saved by Joe. Joe infiltrated the building that Bosgan had the prisoners in disguised as a Devil Beastman Ninja until his coughing gave him away to Bosgan and Harmful Nimp. Harmful Nimp took out Joe and assumed his form. Harmful Nimp sent the Devil Beastman Ninja Corp to attack the place where Kotaro and Reika found the kids taking refuge. Kotaro fought them until "Joe" defeated them and led them to where Bosgan has the prisoners. After Kotaro finds the real Joe, Harmful Nimp sheded his disguise. Bosgan revealed his plans to Kotaro and left as Harmful Nimp and the Devil Beastman Ninja Corps fights Kotaro. Kotaro henshined into BioRider and frees the prisoners. BioRider and Harmful Nimp fought outside as BioRider destroyed his Devil Beastman Ninja Corps. BioRider called for Mach Jabba and charged him. Harmful Nimp climbed a cliff and attacked BioRider. BioRider turned into water to attack him and knocked him off the cliff. BioRider reverted to Kamen Rider Black RX and used his Revolcane to disarm Harmful Nimp before destroying him.
Gynajagram (Episode 40):A strong tiger monster that has red hair on his head and back. He can punch, bite, and is armed with small black boomerangs. He is under Bosgan to fight Kotaro. While Kotaro transformed into Kamen Rider, they fought and Harmful Jaguarma use his boomerangs to attack. Then Kamen Rider transformed into RoboRider and shot him. When Harmful Jaguarma wanted to attack RoboRider, Roborider turn into BioRider and attack back. When Biorider take out his Bio Blade, Harmful Jaguarma also use two boomrrang to fight. When his boormerang was hit off by Biorider's Bio Blade, he still want to attack with free hand. Finally, Harmful Jaguarma was slash by Bio Rider's Bio Blade. He was the last Man-Beast/Mutant.
Strange Alien LifeformsEdit
The Strange Alien Lifeforms unit is led by Captain Gedorian, mostly consisting of alien lifeforms and animals.
Culculten (Episodes 6 & 45 ):Toad-like parasites that thrive in warm areas, able to spew foam from their mouths that induce a high fever in their human victims before laying their eggs in them so they can serve as both incubators and their offsprings' first meal. Three Culculten hatch, using the Sahara house as their base of operation and attempt to kill Kotaro until Shigeru uses ice cubs to drive them off. When encountered again, the Culculten manhandle Kotaro until he becomes RX to out wrestle them before using the Revolcane to kill them each, with the effects of their foam wore off.
Atchpetchy (Episode 9 ):A cactus like alien sent by Gedorian without Jark's consent to turn the Sahara family in cacti-slaves that attack RX until he is forced to fall back when the effects wear off. But Maribaron offers her aid to Gedorian by tricking a girl named Chika into giving up her life to Atechpetchy so his power can be perfected. But RX ruins the scheme and use the Acrobatter to destroy Atchpetchy with his Revolcane.
Dogmalogma (Episode 10 ):A slithering blob-like monster with tentacles for arms, able to spray his slime on them with the slime morphing into a clone. Dogmalogma uses his power to create clones of Shigeru, his frieds, and Reiko as part of Maribaron's plan to use those Kotaro trusts against him. But once he becomes RX, his Kingstone causes the clones to dissolve before he battles Dogmalogma. When the monster attempts to engulf his hostages, RX stops and Dogmalogma kills him with the Revolcane
Flarmiglarmi (Episode 13 ):A jellyfish-like alien parasite with teleportation abilities sent to obtain the G Crystal that was stolen by a rogue Crisisian scientist and his daughter Kirara, with RX driving him away as Kirara learns the G Crystal is found by Shigeru and Kengo. Flarmiglarmi later enters Kirara's body, getting the G Crystal from Shigeru as Kotaro arrives. In spite of warning Flarmiglarmi the danger the G Crystal poses for both worlds, RX is forced to fight him with the Arcobattler before killing him with the Revolcane to destroy the G Crystal and the machine it powered.
Musalabisala (Episode 18 ):A flying squirrel/bat monster. It can breathe fire, use its fangs to inject a toxin, and shoot electrical beams from its eyes. It was used to turn Shigeru and other children into vampires. Kotaro ended up bitten by Shigeru and during a battle with Musalabisala, he was bitten again. Kotaro became Bio Rider to get the injected fluid out of him. Kotaro tricked Musalabisala into thinking that he fell under his control. The trick worked, allowing Kotaro to henshin into Kamen Rider Black RX and fight him. Musalabisala had RX in a pinch until Joe threw one of his sais at him. Kamen Rider Black RX used the RX Kick on Musalabisala before destroying him with the Revolcane. He returned in the Kamen Rider Black RX movie to assist Deathgaron, United Triplon, and Gynagiskhan in their attack on the Kamen Riders only to be destroyed by a team Rider Kick.
Bang-Gong (Episode 21 ):A blue monster who can shapeshift and transform into a shadow. He attacked Joe while he was with an old friend of his named Saila in an attempt to obtain her necklace and ended up injuring Joe in the process. Luckily, Kotaro transformed into Kamen Rider Black RX and battled Bang-Gong. Kamen Rider Black RX got them to safety in Ridron which also tackled Bang-Gong. Bang-Gong later kidnapped Saila. When Joe and Kotaro found her in an abandoned warehouse, they were ambushed by Bang-Gong and the Chaps. Kotaro transformed into Kamen Rider Black RX and fought him. As Bang-Gong swiped the necklace, Kamen Rider Black RX became Bio Rider and followed him outside. Bio Rider took back the necklace and then called forth his Bio Blade, which he used to cut off Bang-Gong's antennas and then kill him. He then got Joe and Salia out of the warehouse before the bomb planted by Gedorian blew it up.
Antront (Episodes 22 & 45 ):A white-haired ant monster. He can create tornadoes and manipulate soil and use it to bury people. He attacked a playground and its surrounding areas until Kotaro and Joe arrived to stop him. Kotaro transformed into Kamen Rider Black RX to fight him (with Shadow Moon secretly observing the battle). When Ant Runt created a boulder, Kamen Rider Black RX became Robo Rider. However, Robo Rider proved useless against Ant Runt as the monster clogged all of Robo Rider's joints with dirt. After transforming into Bio Rider however, he easily maneuvered against Ant Runt causing the monster to retreat and saving everyone who had been buried. He and Gedorian later crashed the battle between Bio Rider and Shadow Moon. Ant Runt trapped Bio Rider and Shadow Moon in an anthill. Ridron freed them and Bio Rider turned into water to attack Ant Runt. He then reverted to Black RX and destroyed Ant Runt with the Revolcane. Antrunt was later revived by Maribaron as part of the Spirit World Kaijin Army.
Lickback (Episode 24 ):A monster resembling a lobster, with scythe-blades for hands and lobster legs between its upper back and shoulders. It assisted Gedorian in his plan to turn the people into vampires. When Kotaro stumbled upon one of the victims attacking people in the car, he saved them before Lickback attacked. Kotaro transformed into Kamen Rider Black RX to fight Lickback before the monster retreated. After an ambush by Chaps, Kotaro transformed into Kamen Rider Black RX and fought Lickback and the Chaps while Joe tried to free Lickback's hostages and fight off the victims at the same time. A kick at Lickback revealed a glowing part on its body. Kamen Rider Black RX used his Revolcane on that part destroying Lickback, thus freeing his vampire victims.
Matbot (Episode 27 ):A white-haired anteater monster with crab claws for hands. The Crisis Empire used it to dig into a mountain to cause a volcanic eruption until Shadow Moon took control of it. When Kamen Rider Black RX encountered Matbot, it attacked the other Crisis Empire officers who fought back. Kamen Rider Black RX escaped the cave-in and ended up engaging Shadow Moon in battle. Gedorian disciplined Matbot at their base and General Jark told Gedorian to use Matbot to capture two children for revenge on Shadow Moon. After defeating Shadow Moon, Kamen Rider Black RX became Robo Rider and fought Matbot underground, who then went above ground while Robo Rider disarmed some bombs. Acrobattler tackled Matbot and Robo Rider used his Vortech Shooter to blast off his right arm. Robo Rider then reverted to Kamen Rider Black RX and destroyed Matbot with the Revolcane.
Gimelagomela (Episode 28 ):A scaley ostrich/dragon-like creature that had small dragon-like heads for hands and an extra mouth on its belly. He can breathe fire from his main head, shoot electricity from the dragon-like heads, breathe steam from the extra mouth, and attack with his tail. Crisis Empire used Gimelagomela to turn people into butterflies and infect them so they could control them. When it attacked a small boy, Kamen Rider Black RX came to save him and battled Gimelagomela, but the victims arrived to help him. Kamen Rider Black RX called for Acrobatter to tackle Gimelagomela but he used his steam attack on him. General Dasmander appeared to have his fight with Kamen Rider Black RX and told Gimelagomela to stay out of it. During the battle, Gimelagomela and his victims interfered and attacked Kamen Rider Black RX. When Kotaro followed the butterflies to their source, Gimelagomela attacked again. Kotaro transformed into Kamen Rider Black RX and fought Gimelagomela. Kamen Rider Black RX used his RX Kick on Gimelagomela, then destroyed him with his Revolcane.
Mundayganday (Episode 29 ):A flea-like monster. He can launch a stinger from his mouth and shoot lasers from its eyes. Mundayganday was the one responsible for killing Kyoko Matoba's parents. He, Gedorian, and the Chaps were attacking a reservoir in an attempt to stop the flow of water into the city because Maribaron was delivering water to people. When Kotaro, Reiko, and Kyoko arrived at the reservoir and were attacked by Mundayganday Kotaro transformed into Kamen Rider Black RX and fought him until Gedorian and the Chaps trapped him a slime-like substance shot from their guns. Kamen Rider Black RX became Bio Rider and destroyed Mundayganday's exo-skeleton with his Bio Blade. He then reverted to Kamen Rider Black RX and destroyed Mundayganday with his Revolcane.
Gazolagezola (Episode 33):A brown lobster-like monster with octopus tentacles on his hips and smaller ones for hair. He can shoot lasers from his claws. He assisted Crisis Empire when they tried to blow up Setoo Bridge. When Kotaro confronted Gazolagezola on a boat, he transformed into Kamen Rider Black RX and discovered Crisis Empire's plans during the course of the battle. As Bio Rider, he used his Bio Blade on Gazolagezola's stomach, removed the time bomb inside him, and threw it into the water. Gazolagezola went underwater and Bio Rider turned into water to follow him to shore. After getting out of Gazolagezola's trap, Bio Rider followed it and reverted to Kamen Rider Black RX. He used his RX Kick on Gazolagezola before destroying him with the Revolcane.
Balunbolun (Episode 36 ):A one-eyed alien monster with an elephant-like trunk for a mouth. It can shoot a beam from its eye, and spew steam from its trunk. It disguised itself as a masked wrestler and brainwashed kids into rooting for him, including Shigeru and his friends. When fighting in a re-match against his latest opponent, it turned out that Bio Rider had merged with Balunbolun's opponent and so he shed his disguise. As the boxer got everyone out of the building, Bio Rider fought Balunbolun who made off with a small boy. After turning into water and catching up to Balunbolun, Bio Rider reverted to Kamen Rider Black RX and fought him. Acrobatter tackled Balunbolun freeing the boy. Kamen Rider Black RX then used his RX Kick on Balunbolun before destroying him with his Revolcane.
Gedoll Ridoll (Episode 42): A louse-like alien that absorbs energy from machines or living things with his mouth-like hands. Gedorian sacrificed his life energy to power it up. He was destroyed by RX's Revolcane. He was the last alien monster.
- Gran Zarius: The Crisis Avenger (44-45): A bird-like monster which was the Grand Lord Crisis' best soldier and worked with Bosgan when summoned by Lord Crisis. While the 10 veteran Kamen Rider team fought the Chaps, Black RX went one-on-one with Bosgan and killed him. Turning his attention to Gran Zarius, Black RX became Bio Rider and destroyed the monster from the inside out. For a time, the 10 veteran Kamen Riders thought that Black RX had been killed, but Bio Rider resurfaced and explained that he bailed out in time before destroying the Spirit World demons. Was used for "Bruticon" in Saban's Masked Rider.
- Spirit World Demons (45): When Kamen Rider Black RX was believed to be dead after the battle against Gran Zarius, Maribaron revived the spirits of Skull Devil #1, Meta Snake, Zuno Warrior, Harmful Nimp, Harmful Mantis Gill, The Lead Burrowing Ten, Erigitron and Ant Runt to kill the other 10 Kamen Riders. Because they are dead spirits, they are all a grayish-white in color. Harmful Nimp's spirit impersonated Kamen Rider 1. All of them were destroyed by Bio Rider.