SHADOW is an inter-demensional organization that is out to take over every world in the Multiverse and are the main villains of Seigi no Senshi Captain Japan.
- Lord-Destruction: The series' main antagonist and the leader of SHADOW, an evil alien entity that plans to take over the Multiverse. He looks-like a living spider-like shadow with a flower-like collar around his neck. Despite him being cunning & ruthless, he also has a twisted sense of humor.
- Lady-Widow: A young pony-like SHADOW member, an expert in Shadow-Magic who can summon demons & spirits and always wants to please Lord-Destruction. She has two Ladies-in-Waiting named Yokoro & Mikishi.
- Yokoro: Yokoro is the oldest of the sisters and is very flirty sometimes. She uses love-based mind-controlling Shadow-Magic and can morph her tail into a scorpion-stinger in battle.
- Mikishi: Mikishi is the youngest of the sisters and is refined and classy unlike her flirty older sister Yokoro. She uses telepathic & telekinetic Shadow-Magic and can morph her mane into a pair of stinger-tipped tentacles.
- Dr. Probe: Dr. Probe is SHADOW's chief scientist that creates the robots for the organization. He appears as a robot with TV monitor-like body with a cartoonish face on it.
- Zaigain: The main field-commander of the Shadow-Kaijin, and a rival to Captain-Japan. He's a insectoid/cyborg that has both a long-sword and a short-sword to fight with and is an expert in hand-to-hand combat.
- Raptors: The main footsoldiers of SHADOW. Raptors are half spider & half lizard and come in two types, Raptors with sickles and Raptors with fur-covered claws.
These are members of SHADOW that are recurring villains that battle Jamiko mutliple times, unlike the monsters of the week.
- Kaizu: Kaizu is a recurring SHADOW member who was once a Raptor that was chosen to undergo an experiment to create a warrior that can match Jamiko's armor. He gained a twisted personality but also gain the same amount of speed and strength as our hero and fights with a sword called the Kagekama. He either works on his own plans, or helps out the monster-of-the-week then Destruction sends to attack the city.
- Iroshi: Iroshi is a recurring SHADOW member like Kaizu that can turn his hands into twin blades. He is a white-insectoid warrior who, unlike other SHADOW-members, has respect for Jamiko as a fellow warrior and fights him many times along with Raptors and SHADOW-kaijin.
These are the monsters of the week of SHADOW. They were created by Destruction and his minons for the invasion of the Mutliverse. They come in many shapes & sizes from giant robots, mass-produced units and mutant-enforcers.
These are the more organic SHADOW-Kaijin created from Lord-Destruction's own DNA. Despite them being free-thinking living-weapons, they have actial names.
- Zuraku Tsurakuchi: A moth/owl/spider-based SHADOW mutant that fights with talons that fire webs and a sonic-scream attack.
- Urakura Zurakurai: This is the commander of the Raptor-Sniper Unit. He's a cunning insectoid SHADOW mutant kaijin who fights with a scythe that doubles as a sniper-rifle.
- Jaisairakai Shiroku: A flea/venus fly-trap based SHADOW mutant that devours anything with his powerful jaws.
- Jayako Zairaichiyo: This spider/virus-based SHADOW mutant has poisonous talons and can fire lasers from his eyes.
- Nago Shiraga: This SHADOW mutant has psychic powers that control people's minds and use them like puppets. He also uses a pistol during battle.
- Owaran Tokaiyakushi: A airborne bird wing-based SHADOW mutant with 8 powerful wings, a sonic-scream and can throw his feathers as projectiles.
- Tsuroko Kairoshi: A blue/green male peacock-spider based SHADOW mutant and Ai Kairoshi's husband. He is the strongest of the pair and has venomous claws.
- Ai Kairoshi: A pink/white female peacock-spider based SHADOW mutant and Tsuroko's wife. She's the fastest of the pair and can spit venomous-webbing from her jaws.
- Shirakushi Noruku: A cat/mantis hybrid SHADOW-Kaijin mutant that can turn his hands into short swords and can fire steam from his mouth.
- Kikyo Modaida: A female moth/fox/spider hybrid SHADOW-Kaijin that is an ambush-attacker, fighting with her claws, blinding speed and whip-like tongues she uses to capture opponents. She has an older brother named Taikyo Modaida who tries to avenge her after her defeat.
- Taikyo Modaida: A male moth/fox/spider hybrid SHADOW-Kaijin and the older brother of Kikyo Modaida. He is more humanoid and smarter then his sister, but he has similar powers to her, such as claws, speed and whip-like tongues to capture opponents. He attempts to avenge his sister against Captain-Japan.
- Matashi Mori: A highly skilled SHADOW-mutant warrior who can fight with a bladed-lance that uses sound-based attacks on his opponents. The claws on his chest can emit a deafening sound that immobilizes his targets.
These are the robotic SHADOW-Kaijin that were created by Dr. Probe as powerful war-mecha.
- Titan-Golem: A massive Shadowkan robot with claws and machine-guns.
- Arachnoborg-Unit 11: A powerful spider-like robot with cannons that fire both electrical-bolts and webbing.
- Dollman: A zombie cyborg that can turn it's hands into laser-cannons.
- Reaper-Robot: A cylinder-looking robot with four powerful tentacle-arms.
- Testament: This was once a S.P.D armored car until scientists of SHADOW modified it for Destruction into a combat weapon with frontal-claws and mini machine-guns.
- Gargoyle: The Gargoyle is a prototype mecha-suit developed by Destruction as an experiment in Mecha-Suit technology with a Raptor as the test pilot. It can fly and is armed with a giant clawed-hand with a laser-cannon built into it.
- The Hand: A massive SHADOW robot that looks like a severed human-arm and has inhuman strength.
- Cyber BugBorg: An insectoid-looking SHADOW robot and has hands that can be either blades or drills.
- Scissorbot-Unit 5: A powerful scissor-based SHADOW robot with razor-sharp blades for arms and a mini machine-gun built into his chest.
These are multiple, mass-produced SHADOW-Kaijin that are created to be in swarms of 5 or more. They are mostly meant to help either the robots or the mutants in attacks. These mass-produced SHADOW-kaijin are also meant to be recurring foes for Captain-Japan to fight.
- Orbs: These are small mass-produced orb-like robots that swarm and devour any kind of machine.
- Battalion-Orbs: These are 3 larger versions of the Orbs, but these are built manly for combat, using their size to ram into opponents.
- Wolf-Hounds: These mass-produced wolf/spider/insect based mutants attack in packs. They can fight with tentacles tipped with claws and a sonic scream attack. These are meant to be recurring mutants for CJ to fight.
- Attack-Orbs: Another variation of the Battalion-Orbs, but these Orb-type robots have powerful arms.
- Worms: These are mass-produced insectoid SHADOW-Kaijin with whip-like tentacles and can fire lasers from their eyes. They attack in small groups of 3 or 4 and are stronger then the Raptors. They are more recurring foes for CJ to fight against.
- Crawler-Drones: These tiny spider-like robots attack in swarms and can devour anything they crawl over, from buildings to even organic lifeforms.
Other monsters: Edit
These are SHADOW-Kaijin that are different then normal kaijin because they don't fit in as mutants or robots.
- Shroud: A living shadow-like creature that Destruction created to be the perfect assassin. He can move through shadows and can morph into either a humanoid form or a bat-like form.
- White-Rabbit: A special rabbit-like SHADOW-Kaijin that was created by Lady-Widow and is based on the White-Rabbit from Alice in Wonderland. She may look like a cute rabbit, but she's really a vampiric demon that drinks the life-force of her victims and fights with two short-swords.