Story spoilers up to episode 9 are unmarked.
Protagonists
Zenichi
The Hero of the series, and the physical component of Kamen Rider Maizen.
- Flat Character: Despite being the protagonist, he experiences less growth than Mikey, Mikage, and Hinata. It's largely justified since Zen is implied to already be a seasoned hero with plenty of unique experiences, while Mikey is a Manchild, Mikage is only now starting to doubt his superiors, and Hinata has a Mysterious Past that the series eventually exposes.
Mikey
Zenichi's pet anthropomorphic turtle, who has a childish streak yet is surprisingly intuitive. Capture by the Illagers has turned him into a monster card that he can temporarily escape with an electric current, becoming the digital component of Kamen Rider Maizen.
Kamen Rider Maizen
Using the Maizen Driver, the earth and nature-themed Kamen Rider Maizen is a suit that fuses Zenichi's body and Mikey's consciousness & data into a singular entity, able to fight as one. It uses monster cards to work.
- Eye Lights Out: Maizen's eyepieces go blank when the Warden card is used, showing that it's effectively autonomous with no human input due to the Warden being improperly contained. Once the Maizen Driver is upgraded with the Evoker System's faceplate, the eyepieces become a shining monochrome after the Warden is fully restrained.
- Finishing Move: Called a Craft & Break, with extra attack names depending on the card inserted.
- Mikey Strike: Maizen throws its shield at the enemy, transforming it into a suspending field. It then drills it into the target with a Diving Kick.
- Guardian Sting: Maizen Guardian Form sandwiches its opponent between its spikes and an apparition of a Guardian, then crushes them further.
- Ender Block Smash: Maizen Enderman Form places Hard Light blocks above its targets, before using the Ender Knuckle to punch them downwards with enough force to crush a Bugman.
- Zombie Trifall: Maizen Zombie Form, together with up to two other converted individuals, slams a giant apparition of a zombie into the target. The zombie used depends on Zombie Form's configuration.
- Creeper Dynamite: Maizen Creeper Form explodes, killing its users unless they have a way to survive the explosion.
- Golem Hammer Throw: Maizen Iron Golem Form increases the Golem Hammer's size to massive levels, then tosses it at the opponent.
- Blaze Rotating: Maizen Blaze Form summons an apparition of a Blaze, before using the Blaze Shaft to hit the target into its rods. The rods begin to spin, grinding the target into a pulp.
- Fusion Dance: As Mikey demonstrates, both he and Zen have equal control of Maizen while transformed.
- Logical Weakness: It operates in the same manner as Kamen Rider Zero-One, transferring its users' consciousnesses to Cyberspace. As a result, the suit can malfunction or destroy Zen and Mikey's souls if something able to harm them enters their operating space, like several tons of TNT or a very angry captive Warden.
Sumanai/Kamen Rider Sumanai
The secondary Rider of the series, Sumanai is a not-so-Ordinary High-School Student with freakish Super-Strength and a voyeuristic streak, which comes in handy since he's the outside world's contact for The Mole within the Illagers. Using the Sumanai Driver, he transforms into the water and technology-themed Kamen Rider Sumanai. Unlike Maizen, his suit operates at standard specifications without a second host. However, the Sumanai Driver's cards are based on actual people, giving him access to more nuanced abilities than Maizen.
- Ambiguously Human: He's a high school student, but is so absurdly strong that the mere act of sneezing can slam Zen down into the floor.
- A Dog Named "Dog": One of his forms is based on a baby named Aka-chan, which is the Japanese word for "baby."
- Does Not Know His Own Strength: Despite being incredibly strong, Sumanai occasionally makes rash decisions that underestimate his strength, such as trying to bear-hug a group of people or quickly putting away a clipboard, both of which end up with them crushed.
- Finishing Move: Called a Sumanai Break. Like Maizen, each form also has its own unique named finisher:
- Banana Missile: Sumanai Mr. Banana Form fires a bunker buster from the Banalauncher.
- Calamity Aka-chan: Sumanai Mr. Aka-chan Form extends the Aka-chan Acro to an absurdly-long length, then slashes downward.
- Hero of Another Story: The seven people trapped in his cards (the masked man included) were only the first out of a list of 26 Sumanai was tasked with retrieving. At the end of the series, he leaves to go rescue the other 19.
- Literal Split Personality: The Red & Blue card lets Sumanai split into two. However, like Mighty Brothers XX, the halves have independent personalities and can become uncooperative if they don't want to get along with each other.
- Multiform Balance: Albeit in a different way from Maizen, as Sumanai's forms are more about the right tools for the right job than combat style.
- Default: An Absurdly Sharp Blade that can cut through anything, and is Sumanai's preferred way of fighting.
- Mr. Banana: A multipurpose missile launcher for targets too far away for Sumanai to hit with a blade.
- Aka-chan: A Super Serum for quick bursts of strength, plus a Sonic Scream to disorient targets and Wolverine Claws to finish the job.
- Gin-san: A hammer that locally alters time, for cleaning up after everything's said and done.
- Red & Blue: Abilities suited for infiltration and rapid execution of weaker targets.
- Money: The Cape, who fights as the traditional Flying Brick.
- New Powers as the Plot Demands: Unlike Maizen, we are never shown where any of Sumanai's cards come from or how they came into his possession, and he just so happens to have the perfect new form for every unique situation he runs into. The only exception is in #10, when he finds one in a lockbox while raiding the Illagers' headquarters.
- Nice Guy: Despite his Super-Strength, Sumanai is actually infallibly polite in his treatment of Zen and later Mikage, to the point where he adds "Mister" to the names of all of his forms.
The Masked Man
A mysterious individual who provides Sumanai with his equipment based on combat and observation data from the outside world. He, in turn, gets his technology by pretending to be an Illager within their secret base.
- Satellite Character: He exists solely to study Sumanai's activities in the outside world and any new pieces of tech he and Zen run into, and to explain why Sumanai is already kitted out from the beginning of his debut. Justified, as he is a Decomposite Character of the real Sumanai. #12 also implies in a Freeze-Frame Bonus that he may have been sealed by the Illagers the same way Mikey was, explaining why he knows so much about them and is able to do what he does.
Supporting Cast
Hinata
Zen's romantic partner. Though she seems disconnected from the plot at first, Mikey quickly learns that Hinata and the Illagers are perhaps more familiar to each other than Maizen could ever hope to be...
- Escaped from the Lab: Was a target of experimentation by the Illagers as a child, until Mikage convinced her to escape.
- Foreshadowing: The series's opening always labels Hinata as "the heroine" in the credits, even though she doesn't actually do much fighting as a support character. This changes once her true nature is revealed, unlocking Mikage's Super Mode as a second two-in-one Rider.
- Fusion Dance: The only individual that invokes a transformation for Kamen Rider Mikage as a card, powering him up into an Allay-based form and allowing the two to fight as one like Maizen.
- Human Disguise: An Allay that a young Mikage rescued, and has been hiding her powers since.
- Instant Expert: Implied to be doing some of Kamen Rider Mikage's fighting once the two fuse into its Super Mode, even though Hinata has no real fighting experience whatsoever. It's suggested, consequently, that her link to Mikage as an Allay is feeding her the requisite expertise.
Yorozoya
Sando, Homura, Yun, Pieko, and Zearu
Five friends, of whom their de-facto leader is a Recurring Extra. Though powerless, they carry the same strong sense of justice as our heroes and are willing to throw themselves in danger to save the day.- Ambiguous Situation: Zearu's human avatar is conspicuously absent from the group's full appearance, making it unclear if he doesn't exist or is a Decomposite Character with an unknown fate. Later episodes suggest the former is true, and in the epilogue one of Sando's friends takes his role instead.
- Anime Hair: The entire group stands out from all of the other civilians due to having unnatural hair and eye colors. Sando is green, Homura is red, Yun is yellow, Pieko is pink, and Zearu is purple.
- Empowered Badass Normal: Sando secures Trooper belts for the entire group in #8, enabling them to transform into specialized models that have additional markings for their Color Motifs. Prior to that, he was the first recipient of Maizen Zombie Form's abilities in #4, temporarily letting him use a perfect copy of the suit.
- Token Non-Human: Zearu is a dog. Or is he Zearu's dog, like how Mikey is Zen's pet turtle?
The Illagers
Mikage/Kamen Rider Mikage
Mikage/Kamen Rider Mikage/Warden Bugman
The leader of the Illager organization, Mikage is a surprisingly youthful-looking Evoker who leads his compatriots in their quest for world domination. However, he's been beginning to have doubts after meeting Hinata...By sealing his former subordinate within a monster card, Mikage is able to use the Maizen Driver's technology without a second host, using a new model called the Evoker System to transform into Kamen Rider Mikage. Following his defection, the masked man upgrades the Evoker System to function without cards.
- Beauty Equals Goodness: The most human-looking Illager, and also the only one with a proper moral compass able to fight on his own.
- Expy: Kamen Rider Mikage Hinata Form is a very blatant retread of either EvilytyLive or Sinspecter, both being blue, angelic super forms that combine light and darkness.
- Forgot About His Powers: Played for laughs; Zenichi ties him up in #8 to ensure he doesn't try to run off on his own and worsen his injuries, but the next episode has him remember he's an Evoker and therefore does not need to transform into Mikage to use his powers. Thus, he summons a pair of jaws to cut off his restraints.
- Heel–Face Turn: After his former subordinate escapes and leaves him for dead in the city, he leaves the Illagers entirely and joins Maizen and Sumanai.
- King Mook: Mikage's Kamen Rider form is basically just a souped-up Evoker Bugman. Its real strength comes from the fact that he is already an Evoker to begin with, meaning he is the only one who knows the full range of uses for its abilities. His abilities while transformed take on a more original flair once he fuses with Hinata, giving him the power of an Allay to work with.
- Love Redeems: Develops a sense of humanity by protecting Hinata, eventually doubting his leaders and ultimately defecting for her sake. While a Hopeless Suitor thanks to Zenichi, Hinata's true nature unlocks his full potential, and their full reunion on the battlefield has them unite as one to take down the Iceologer.
- Rule of Symbolism: The main difference between the Maizen Driver and the Evoker System are their unique faceplates; the former uses a stylized "MZ", while the latter uses a set of sliding blades resembling an Evoker's jaws. This represents how Maizen is a Rider created from two friends acting in unison (Zen and Mikey), while Mikage is a Rider created by one person (Mikage) forcing another (the Iceologer) into submission. Once Hinata gives Mikage his Super Mode, the Evoker System's faceplate is broken off in combat and repurposed to suppress the Warden card's malevolent nature, symbolizing how he no longer needs to force other people into giving him power and showing that true strength comes from friendship, not hatred.
- Summon Magic: The Evoker System's cards summon constructs representing the corresponding mob's abilities instead of transforming Mikage. Except for Hinata's. Or more accurately, the Allay's.
- Yin-Yang Bomb: After using Hinata's card, Kamen Rider Mikage transforms into a being resembling a halfway between an Allay and a Vex, two supernatural and vaguely-angelic mobs on opposite sides of the spectrum.
Bugmen
The series's Monster of the Week, created when an Illager uses a belt to transform with a monster card.
- Good Old Fisticuffs: Part of the reason they aren't as strong as Maizen is because they don't get weapons, relying on their fists and whatever secondary abilities their card has to solve problems.
Troopers
Mass-produced Riders used by the Illagers to give their Mooks a power boost.
- Expy: Basically copyright-free Riotroopers; both are brown mass-produced Riders made by a villainous organization.
