The Protagonist of the series, he lives on a private island north of Hokkaido called Kamui Island with his brother Kotaro. Short after sending off his brother Kotaro to study overseas, he found an injured lady named Karen, who later became his trainer to prepare him for a tough battle in case something happens to his intelligent brother.
- Alliterative Name: His initials starts with "T."
- Big Brother Worship: Teppei looks up to his brother Kotaro alot, and would mention how he couldn't outsmart his intelligence.
- Big Ol' Eyebrows: Well, he certainly has the thickest of all the main cast.
- Came Back Strong: With the aid of Hokuto, X and Teppei underwent a Mid-Season Upgrade after the former was reduced to scrap, with Teppei gruelingly injured.
- The Chosen One: At the very beginning, Teppei's only mission was to head inside of the Empire to get his brother outta there, but by the moment Teppei awakens his true form, he was given literally no choice but to save humanity.
- Color Motif: Stationed militant, Camilla judges people by color. He originally asked Teppei what his color motif was, who obviously has no clue in what he was talking about. After their battle, Camilla concluded Teppei as "A man pure as white, yet not completely white, with compassion red as fire, yet not truly red; just like the sun, dazzling to everyone's eyes."
- Coming-of-Age Story: The story as a whole can be seen as Teppei's development towards mental and physical maturity.
- The Confidant: Of Demon General, Meimu. The then dying Meimu initially wanted Teppei to help him pass his confession to Hokuto, his little brother, in regards to the truth behind the nuclear incident in which Hokuto suffers from, but Teppei decided not to reveal it to Hokuto, even when Hokuto clearly understands that Teppei is hiding information from him, Teppei just won't spit it out, because he felt that it was unnecessary to break the bond that they finally patched up after all their years of separation.
- Declaration of Protection: One of Teppei's major motifs, indicating he would move heaven and hell to protect his loved ones; in this case, his brother. Kurumada specifically wrote his Image Song with this theme.
- Expy: As part of the Masami Kurumada protagonist family, he's destined to follow the bloodline of Ryuji Takane, and the Legendary Seiya.
- Friend to All Living Things / Fluffy Tamer: It was implied that he could befriend and cuddle a full grown WILD BEAR at the age of roughly 7, not to mention Teppei also Speaks Fluent Animal given he understood the bear's situation as being pregnant and wishes to have some fish so that she can give birth to a healthy cub.
- Grappling-Hook Pistol: One of the main funtions of Teppei's Messiah Fist. His "Shining Knuckle" attack is the power enhanced version of this function.
- Gratuitous English: "X! Omae wa ore no baadii da!"
- The Hero
Teppei: "How dare a man have his heart be willingly controlled by others? A true man has all the responsibilities to control his feelings and desires with his own conscience."
- Action Hero: He'll be willing to go to great lengths body-guarding his non-action brother Kotaro.
- Celibate Hero: Camilla and Demon General Salome both had toyed with Teppei's various desires,note and seduced him with their spells during their battles with him. But Teppei, while still under their spells, overcame their seductions out of sheer will and was able to talk to them with a cool-headed straight face. Teppei is not by any means, saying he absolutely won't share his feelings or desires with others, but as in when it comes to the things that he needs to solve first, he will get through those things first.
- Chronic Hero Syndrome
- Heroic Willpower
- Humble Hero: This is who he becomes after his Idiot Hero phase below. Most predominately clear in vol. 14 of the manga, where he encounters the heel-face turned Juggler, who's face was revealed to have been a clown face since birth. But instead of laughing at him, Teppei commented how his own looks aren't any better than Juggler's; mentioning since Juggler repented for his wrongdoings, Teppei gives him his Power of Trust, and encourages Juggler to have the confidence in stepping up to be the kind of person who he truly wants to be.
- Idiot Hero: He grows out of it eventually, but Teppei's VERY MUCH this trope for a good chunk of the series. It takes a double whammy of him almost getting X killed and Fou telling him how much of a fucking loser he is for him to wise up.
- Magnetic Hero: X despises him, Fou and Ron beat him up in battle and never lost, Hokuto never wanted Teppei's gratitude for grading up X and insisted that they remain "enemies", and even Karen initially wants to ignore the then dying Teppei to continue on her quest. But then, why did all of these B'ts and big shots keep assisting, and eventually, side with him? It's due to: 1) his sheer determination, 2) his simple yet persuasive philosophy, 3) that "radiant" charisma of his, and 4) that aforementioned charisma triggered the inner mentors of all his acquaintances to take him under their wings and witness his growth.
- X Marks the Hero: He has an "X" scar right on his forehead.
- Hunk: Teppei's proven to be manly and pretty at the same time. Thanks to the anime character designer standing true to the manga art style, viewers can noticably tell how Kurumada designed Teppei to be a lot more handsome than his predecessors.
- Kiai: Earned one in their pachinko game.Teppei: "AH~TETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETE—-TA!!"
- Kid Has a Point: While all Machine Empire militants were swearing their loyalty towards their Emperor and praise him as their god and claiming him as their savior to mankind, Teppei keeps pounding each and every one of them with questions along the lines of: "Dude! If your Emperor is so righteous, why did he order a massacre on innocent people just to abduct one person?!" until someone's conscience kicked in some sense. The Spirit Generals certainly did.
- Kill It with Fire: Teppei's initial Finishing Move in the anime is "Break On", a pillar of flames. He ditches that later on.
- Light Is Good: Teppei's theme revolves around being The Light and the charismatic influence towards the people he encounters, along with his characteristics below:
- Cue the Sun: Whenever people talks about him, the image of the sun, or the sun itself will always pop up.
- Light 'em Up: When he awakens his inner Power of the Sun, his body will glow up, his hair would turn bright red, and he will make his enemies Disappears into Light.
- The Power of the Sun: Teppei's awakened supernatural power. He becomes the key person in defeating Raphaello.
- Power Glows: Comes with The Power of the Sun package, whether with or without his armor, he will glow once he triggered the power button.
- Shining Goodness: His attack is called "Shining Knuckle," and it's damn shiny indeed.
- Meaningful Name: His first name means, "Iron Soldier," while his last name means "High Palace," in which can also be an extension for "Heaven." Combine them, his full name literally means "The Iron Soldier from the High Palace."
- Mid-Season Upgrade: The anime and Kurumada's illustrations were not completely stable on this, but overall, Teppei's Battle Gear armor went from silicone-ish white to cream-yellow. And no, Battle Gears were not made from metal materials.
- Mr. Fanservice: When he was recovering during X's Mid-Season Upgrade, Hokuto had already stripped off his clothes leaving himself completely exposed wearing only his boxer briefs note in the manga, but the anime took it further in taking out his boxers all together, giving him Scenery Censor and Lens Flare Censor from the incubator he sleeps in.
- Female Gaze: Unlike his expy who has armor protecting their crotch section, Teppei's battle gear doesn't. Therefore the audience were quick to notice his cute bun-shot in his first Transformation Sequence, and were displeased the animation production took out that eye-candy for his upgraded sequence.
- Power Fist: His weapon, The Messiah Fist gauntlet is a hand power enhancer, GPS, and wire weapon that has marble hooks attached to the front of each wire. Teppei can control the strength of his wires to be either penetrating floss, or to simply act as a whip.
- Rapid-Fire Fisticuffs: Also earned one in their pachinko game along with his Kiai.
- Sacred First Kiss: In the manga, Teppei's kiss was stolen by a guy, and he was noticeably squicked by it.
- Shout-Out: Teppei's name is most likely a direct tribute to the lead character, "Teppei Uesugi" from manga, Ore wa Teppei note created by Kurumada's idol manga artist, Tetsuya Chiba, who co-created Ashita no Joe.
- Smarter Than You Look: It's quite hard to pinpoint your true intelligence when you're competing against an academically Born Winner older brother. Therefore, Teppei tends to feel he's Book Dumb, and opts to mold himself to become the athletic performer of the Sibling Team rather than improving his academics. However, it was because he was raised with a big brother stuffing him with abnormal amounts of technological knowledge since birth, that he unknowingly blinded himself to the fact, through a few subtle implications within the story, that he actually did mastered all the teachings Karen had passed down to him, including the Machine Empire's 300 years in global advanced Mechanical Engineering knowledge and skill set.
- One scene in particular caught a clear glimpse of Teppei's intellect, where he just looked at X for a spit-second while X barely walked 3 steps on the ground to know X couldn't perform well due to X's leg joint being loose. Hence, that's how X ended up with Teppei's bandanna tied to his leg.
- Student and Master Team: With Karen.
- Suicidal Overconfidence: Teppei suffers from this early on. It takes X essentially dying for him to start realizing he can't act stupid, if only for the sake of others.
- Super Strength: He can break a giant solid rock in the size of a mammoth into two...with one bare fist. His grip and fist power goes Up to Eleven when he equips his Messiah Fist gauntlet.
- Tender Tears: People tend to mistake Teppei's constant shed of tears as Manly Tears due to his Kurumada protagonist status, but rather he is this because he's actually a pretty sensitive guy. Teppei cries over almost anything from Kotaro leaving to study overseas, his pet pony being stabbed to death by Metalface, to Juggler's death, and especially noticeable when he cries upon seeing Amigo's corpse in the anime.
- When He Smiles: Teppei rarely has chances to genuinely smile. So when he does, it will be a Heartwarming Moment to everyone surrounding him. Said moment may or may not Cue the Sun.
- Younger Than They Look: Compare to his expys, or even besides his own older brother, he's noticeably more mature and masculine-looking. Yet he's only 14.
Teppei's older brother and Deuteragonist of the series. He's a 16 year-old Professor in Robotics who upon releasing a thesis in AI Robot Technology, got kidnapped by the Machine Empire.
- Action Survivor: He's just a certified scientist/engineer who has no martial arts, nor military training whatsoever. Therefore he has to greatly rely on his own intellect, survival instincts, and the might of his brother's comrades and or anyone he befriends around himself to survive his whole abduction tale.
- Big Brother Instinct: Even when he's been captured, a part of his mind has been thinking about Teppei's safety.
- Child Prodigy: He solved complicated formulas at the age of 7, and was enrolled into a Berlin university at the age of 11. Aging on to Teen Genius when the storyline started.
- Cool Big Brother: Of Teppei, he builds a really cool high-tech secret hideout inside their backyard tree and allows Teppei to freely play in it.
- Defiant Captive: The perk for him being a young guy, and the most recent captive amongst all other scientists who were abducted before him. But Kotaro is exceptionally more defiant since he knew his brother is on the road to rescue him.
- Determinator: Just as his little brother is determined to rescue him no matter the circumstance, Kotaro does his part in trusting his brother to rescue him; giving his all to survive Underhell, and come up with the formula to defeat B't Raffaello.
- Distressed Dude: Got kidnapped by the Machine Empire to force him to work for them in finding the resolution on how to stop the ever growing horror, B't Raphaello. He refuses, and was banished to the Underground doing slave labor. But that didn't stop him in thinking of ways to get out of that place.
- Doing Research: His main mission in story, he needs to find the math solution to destroy B't Raffaello before it eats the Earth up.
- Expy: He's pretty much the Prince Marg to his little brother, Teppei. Only that Kotaro's more than 1000 times smarter than that expy of his.
- Kurumada series-wise, most fans figured he's a mix between Andromeda Shun and Aries Mu.
- Hard Work Hardly Works: A tiny episode of his childhood with Teppei implies how Kotaro originally designed a pair of fishing rods meant for Teppei and himself to fish "more effortlessly" than using the adult rods. But in the end, Kotaro barely had any catches, while Teppei, indeed effortlessly, emptied the entire river picking off over 2 fishes per second, overflowing buckets full with fish. While at the same time, giving Kotaro all the credit for making this awesome rod believing it was the rod, and Kotaro's genius, that's super.
- Meaningful Name: The first character of his name in Kotaro, means "Steel," in which his nerves can back it up. Combined with Teppei's first character, they are "Steel and Iron".
- Nerves of Steel: He sure damn is. He didn't lose his cool nor blink an eye when being neck-wired right on the first episode.
- Non-Action Guy: Though he generously showed us how to write formulas on the ground in a hotblooded mindset.
- Odd Couple: Ron ends up aiding him for the most part in the manga.
- Playful Hacker
- Power of Trust: Kotaro's major motif. He's a man who greatly trusts in his brother's talents, abilities, and his word in fulfilling the promises towards those who he swore to. Kotaro himself is also a man who executes his words with extreme caution and weight, therefore, every opinion he makes will always be backed with his full attestation. Like Teppei, Kurumada also wrote his Image Song with this theme.
- The Professor
- Rapid-Fire Typing: Whenever he can get his hands on a computer to do research, this is how he will perform.
- Teen Genius: He released a study proven the ability to create biologically intellectual robots in a press conference at the Machine Expo at the age of 16. Not to mention he already obtained his Ph.D long before that.
- Telepathy: In the final chapter of the manga, Kotaro's conscience was thoroughly in sync with his brother to the point where he was able to perform telepathy to Teppei across space; signaling Teppei to not concern of him being in the way, and just give B't Raffaello the final blow.
General of the West, former Donor of B't X and current Donor of B't Shadow X. She escaped from the Machine Empire upon understanding their country's plan in destroying mankind.
- Action Girl
- Badass Normal: Can destroy an entire Ryukaon squad on foot and beat Metalface in hand-to-hand combat. Not to mention that she also went on a few rounds with Raphaello on foot.
- Doing Research: She spent 9/10ths of her story time out of the action spotlight, digging deep into researching for the key elements that can defeat B't Raffaello.
- 11th-Hour Ranger: Karen eventually went back into action with Shadow X as her B't.
- Fighting with Chucks: Her weapon of choice, and can flash electricity with it.
- Gadgeteer Genius: Taking only the core parts of the B't Ryukaon scraps that she defeated on Kamui Island, the rest of the materials that she used to build Shadow X was mostly out of...god knows what they were.
- She's also the one who created Teppei's Messiah Fist out of B't Raffaello's cell.
- Morality Pet: Of Metalface.
- Motherly Scientist: She's pretty much one of the only few Donors who pampers their B'ts like their own children, X and Shadow sure are spoiled.
- Seeker Archetype: Her major motif. After being jailed and fled for questioning her authorities regarding B't Raffaello and the policies her government, Karen sets herself on the quest to search for answers and the key elements to take down B't Raffaello. Which in her case, scouted Teppei and found the key element—"Piece of the Sun." Kurumada wrote her Image Song with this theme.
- Sexy Mentor: Of Teppei.
- Stripperiffic: Whether Teppei is around her or not, she doesn't mind strolling around either half or completely naked.
- Student and Master Team: With Teppei.
The General of the South and Donor of B't Je t'aime, he's a priest who took in local orphans under his care.
- The Atoner: He almost let his best friend kill him over the whole dead little sister thing.
- Badass Preacher
- Chick Magnet: It's heavily implied that Karin, his old friend Lily, and Karen all had the hots for him.
- Hollywood Atheist: As a child, Foh lacked tact.
- Love Triangle: The audience can see pretty clear that Karin likes Foh, but Foh's into Karen, and Karen has feelings for Foh. But unfortunately All Love Is Unrequited within the story.
- Musical Assassin: Foh uses a violin bow as a weapon to go along with Je T'aime's attacks.
- Pocket Protector: Foh's Bible saved him from a spear attack.
- Rugged Scar: He has a big scar in the form of a Cross on his back, but it's origins was never mentioned in the story.
- Sexy Priest
- The Stoic
The General of the East and Donor of B't Raidou, he is the highest ranking Spirit General of the four, and the most loyal of the Spirit Generals to the Machine Empire.
- All Chinese People Know Kung-Fu
- Amazon Chaser: Ever since Aramis carved his chest with a "bolt," her presence is on his heart forever.
- Arrogant Kung-Fu Guy: He has amazing skills to back him up, however.
- Blade on a Stick: His weapon of choice, and is often seen waving it around.
- Bruce Lee Clone: Infamously known for his flashy Kiais.
- Combat Pragmatist: When he realized the Machine Emperor was only a humongous brain powered by an electrical water tank, he just went straight for the plug.
- Heartbroken Badass
- Odd Couple: He spends most of his screen time working with Kotaro in the manga.
- Undying Loyalty: Towards the Machine Empire
- Sixth Ranger
- The Stoic
- Unresolved Sexual Tension: Towards Aramis. It was shown that he actually cares about her, and constantly asks himself why a beautiful lady like her keeps insisting on a Tomboy appearance, and was fiercely heartbroken upon her Heroic Sacrifice.
The General of the North and Donor of B't Max, a General Medical Physician who is also a Master Engineer of B'ts. His birth year is roughly late 2011 to 2012, since it's revealed he was 9 years-old during the summer of 2021.
- The Engineer / The Medic: He's got both jobs on hand, and is the master of this field for the frontlines.
- Future Spandex
- Hidden Depths: In the manga of all characters, his birth year, age, and family background was the most thoroughly written. Paving way to his relationship with Meimu, his Long-Lost Relative.
- Incurable Cough of Death: Hokuto suffers from radiation poisoning. During at least one point in the series, it catches up to him at the worst possible moment.
- Labcoat of Science and Medicine: And he fits it perfectly! Interestingly enough, when he decides to take up a battle, he would take the coat off.
- Magic Staff: His weapon of choice, though it's more like a Cool, But Inefficient Remote Control over anything else.
- Martial Pacifist: He doesn't like violence, nor take on any battles unless he has no choice. Even when he steps up to the plate facing Demon General Dr. Poe with his Battle Gear turned on, he chose the non-violent quiz route to play with him first.
- The Smart Guy
- The Stoic
- We Can Rebuild Your BT: Hokuto aids in upgrading X and fine-tuned Shadow X.
X the Kirin
The title name holder and Supporting Protagonist of the series. A Male B't manufactured by the Machine Empire in the form of the Chinese mythological animal, Kirin. He has a prideful tough-guy personality, originally was programed to swear loyalty towards his original Donor, Karen the General of the West Wing of the Machine Empire. Upon taking Karen out of the country for exile, his function died out midway and was taken back to the Empire to be disposed. 5 years later, he was awakened again from sensing Karen's blood reentering his body, only to find himself dumbfounded to see that the person who gave him Karen's blood was through a boy name Teppei. Legend says that when a Kirin descends from Heaven, the land shall be saved from evil.
- Aloof Big Brother: To Shadow X.
- Battle Aura: X's Prism of Aura, which doubles as a Super Mode.
- Came Back Strong: With the aid of Hokuto, X and Teppei underwent a Mid-Season Upgrade after X was reduced to scrap, with the latter gruelingly injured.
- Character Title: This series is named after him, but the POV is on his Donor, Teppei.
- Cool Mechanical Kirin: With WINGS!
- Deadpan Snarker: His attitude would come off as a complete Jerkass sometimes.
- Lightning Bruiser
- Memento MacGuffin: Teppei's red bandanna, in which greatly helped served as X's identity indicator when both X and Teppei were being affected by Camilla's illusion flowers. Teppei originally used his bandanna to hold X's left leg in place until it wasn't needed after X's Mid-Season Upgrade; but X ended up liking the bandanna and asked Teppei to tie it back on his leg as a token of their friendship, and also serve as his sign of loyalty towards Teppei.
- Mid-Season Upgrade: From silver to gold!
- Robot Buddy: Yup. ...No, seriously!
- Undying Loyalty: At first he is this with Karen, but ever since Teppei overtook him as his Donor, he became even more inseparable towards Teppei than to Karen.
- Ungrateful Bastard: He felt like complete shit when he realized the person whom he thought was his master was actually a spunky kid.
Shadow X the Kirin
A Female B't manufactured by Karen herself in the form of the Chinese mythological animal, Kirin. Karen has been slowly putting her together during the 5 years of her stay at Kamui Island. At first Shadow was uncontrollable, and often went berserk in flying out of hand trying to head to wherever X was located. It wasn't until Teppei dragged her to Hokuto to be stabilized that she was able to create a personality of her own.
- Annoying Younger Sibling: By sharing the same blood from Karen, she is legitimately X's little sister. In the manga, she's pretty hyper and excited upon meeting her brother for the first time after her fine-tune, yet the stiff-brained X doesn't really know how to handle her lively spirit.
- Canon Immigrant: Shadow was a filler character who was originally planned to be nurtured through the anime. But TMS Entertainment found themselves Screwed by the Network on short notice and couldnt develope her character in time. Kurumada saved both TMS and his dear work by officially making Shadow canon within the manga.
- Cool Mechanical Kirin: And she has wings too!
- The Cutie: She calls X "oniichan" with an affectionate rub on the neck in the anime, and was shown Up to Eleven throwing major squees in the manga.
- Dark Is Not Evil: She may have a black coating, but that personality of hers totally throws the term "evil" out of the equation.
- Distaff Counterpart: Of X, she's made from spare parts of various B't Ryukaons and other materials.
- Fragile Speedster: She's shown to have exceptional speed in the manga.
- Genki Girl: She literally spins around in circles upon meeting X for the first time after her fine-tune.
- Hair Decorations: Though she's made of metal, Teppei manages to doll her up by decorating her horn with half of the bandanna he wrapped X's leg with.
- Plucky Girl: It's pretty obvious that she's one fearless little gal when she had her first show-down with B't Madonna in the manga, Shadow even had fun driving Madonna crazy with her speed skills.
- Replacement Goldfish: Karen created Shadow X to replace X as her B't in case Karen ever confirmed X was impossible to repair, and needed to face off with The Machine Empire. Blessed X was alive and willingly teamed up with her pupil, otherwise Shadow might have ended up with either no owner, or eventually paired with Teppei.
- Token Mini-Moe: Despite her size, in a B't team full of stoics, she is definitely this. Plus, she's the youngest to be born anyway.
Je t'aime the Phoenix
A Female B't manufactured by the Machine Empire in the form of the Chinese mythological animal, Phoenix. She has a prideful personality and can be a bit inflexible with people.
- Glass Cannon
- Instrumental Weapon
- Make Me Wanna Shout: Her high-pitched screeches exploit a B't's sound-based vulnerabilities.
- Proper Lady
Raidou the Dragon
A Male B't manufactured by the Machine Empire in the form of the Chinese mythological animal, Dragon. His personality is mostly stoic, and obeys Ron's orders in the most absolute fashion.
- The Big Guy
- Lightning Bruiser
- Out of Focus: His Donor took most of the screen focus while his head ended up being constantly cropped and doesn't really have any good close ups in the anime.
- The Stoic
Max the Turtle
A Female B't manufactured by the Machine Empire in the form of the Chinese mythological animal, Turtle. She has a serious but witty personality, and would be willing to talk to other people beside her Donor Hokuto. She could get emotional from time to time.
- Cool Ship: She's a huge computer laboratory who can fly the sky, run in the underground, and that can fit 1 average sized B't for full repair, and probably one to two persons for full medical treatment.
- Cry Cute: She can get pretty teary when it comes to family bonding.
- Hates People Yapping Inside Her: She doesn't like people making too much noise inside her; think of them as butterflies in your stomach, and she will tell you by shrugging you around, which will feel as if theres an earthquake going on.
- Macross Missile Massacre: If you piss her off and make her move into battle mode, she'll give you a load of this.
- The Medic
- Mighty Glacier: She's infamous among the Empire for having unparalleled defense, but this doesn't stop Dr. Poe from destroying all of her except for her head.
- The Smart Girl
- Stone Wall: She has the Empire's toughest defense system built in her.
- Tank Goodness
The 13 Stationed MilitantsUpon thousands of stationed military posts The Machine Empire placed around its country for defense, starting to where Fou's station was located, these 13 posts marks the shortest lineup route Teppei has to go through in order to enter The Tower. Based on Fou's observation, most stationed guards are way too prideful, and achievement-oriented to bother with team play, therefore, each militant would most likely go one-on-one with their invaders and not report their failures to other posts if they were to lose in battle.
- Color Motif: Camilla judges people by color.
- Expy: Of Papillon Myu the Specter from Saint Seiya.
- Master of Illusion
The Death God
- Dark Is Evil: The Death God and his Bat B't are a very straight example.
- Cybernetics Eat Your Soul: Invoked. He got hit so bad with it that the Death God is not capable of uttering a word. Goes in outright Tear Jerker territory when you see how his area was before, and what it has turned into.
- Cue the Sun: Played straight on two counts. Night falls on his area as Teppei starts fighting him, and he gets his Heroic Second Wind just as the sun rises, channeling the Power of the Sun for the first time.
- Four Is Death: The fourth opponent to Teppei and X, and a Death God.
- Wake-Up Call Boss: This opponent actually puts Teppei and X on the ropes, and this is where Teppei learns he has to treat X as more than just a tool to bring out his power.
- Curb-Stomp Battle: Gets stomped by a passing Teppei who has just awakened X's true power.
- Dirty Coward: He lets Foh through because he knows he has not a snowball chance in hell against him, even though he is a traitor.
The Three Dark Knights: Lai, Leon, and Mila
- Expy: Of those three guys from Saint Seiya, the three Silver Saints (Canis Major Sirius, Musca Dio, Hercules Algethi) ganging up to kill Seiya before getting killed via Curb-Stomp Battle.
- Filler: The Dark Knights themselves were not filler villains to the storyline, but their fight was expanded to 3 episodes to serve as foreshadow to Teppei's connection with the Sun, and the potential he has.
- Ermine Cape Effect: Proclaiming as the Prince of Darkness, Myslim was dressed more on the practical dandy side with a frilly pink blouse paired with a red long coat. Still fancier than other fellow antagonists Teppei faced though.
- Green and Mean: He has long seaweed-shade green hair, with an unhealthy greenish complexion.
- Hydra Problem: His B't Lanenia is based on the mythological animal Hydra, with nine heads and can regrow if one head is damaged.
- Medusa: Rare male example. His powers revolves around the motif of Medusa, armed with a gauntlet call "Viper Whip", which has mechanical snakes mounted to the fingers to shoot out venom that can weather-down whatever it contacts into sand.
- Red Eyes, Take Warning
- Taken for Granite: What he can invoke on his opponents. He tries this on Teppei, who is VERY lucky to have an upgraded X to protect him.
- Wake-Up Call Boss: Serves as a preview of what the Demon Generals can do, and how they should not be taken lightly.
Second of Demon Generals to appear in the anime. He was Foh's childhood friend, and seems to hold some kind of grudge against Foh. And the two of them faced-off in a private battle.
- Childhood Friends: With Foh.
- You Killed My Sister: The reason Quattro wants to kill Foh. And Foh has no objections to it.
- Redemption Equals Death
SalomeThe third and sole female Demon General that Teppei faced in the path towards the Empire Tower. She can control the minds and actions of others when they hear a music piece that she performs a dance to. Her name and character was based on the seductiveness from The Bible who triggered the death of John the Baptist.
- Broken Bird
- High-HeelFace Turn: Of all the Demon Generals, Salome was the only one who decided to help Teppei once she regains her faith in humanity. Unfortunately, Juggler had different ideas.
SapphireThe fourth Demon General blocking Teppei from the Empire Tower, he is obsessed with beauty, and has a cybernetic body made of precious stones. Sapphire encased Max in a precious stone, who has both Hokuto and Foh onboard, leaving Teppei the only person to deal with him.
- Camp Gay
- Depraved Homosexual / Villainous Crush: To Teppei, he is very interested in his "light" and wants to literally "own it".
- "Pop!" Goes the Human: This is what Sapphire gets for harassing Teppei enough to "throw light beams onto him." Though Sapphire was initially enjoying the sunbath, little does he know that he was the one unworthy to "own the light."
- Shout-Out: His character design was based on IZAM, the vocalist from the Japanese 90's Visual Kei band, SHAZNA.
- Childhood Friends: Of Hokuto, they were classmates of the same year from the Machine Empire Academy.
- Evil Genius: He's smarter than Hokuto, and beat him on the exam for the rank of Demon General.
- Jerk with a Heart of Gold: His true personality. Back when they were classmates, despite being prideful, Poe has always considered Hokuto as a close friend, and was shown in a scene where he sneaked into the cell that Hokuto was punished from the rank-up exam to give him food and drinks.
- Mad Scientist: He's interested in genetic manipulation and does research by combining different animal species together, which includes deconstructing the Empire Examiner that banished Hokuto to jail back when Hokuto failed the rank-up exam.
- Split Personality: He mainly switches between a Jerkass Techno-babble Geek, an Ax-Crazy idiot, and an apologetic Shrinking Violet.
The third and last out of seven generals to appear in the anime. In the manga, he's the 6th person to appear.
- Brainwashed and Crazy: His true identity was completely erased from his memory, and that includes memories of his family in which Hokuto is part of.
- Demoted to Extra: His status to the plot was originally higher in the manga, but then got washed down in the anime because his time in the anime arrived in just before he can explain himself properly in the manga.
- Long-Lost Relative: Meimu, is Hokuto's older brother named Subaru, whom Hokuto thought was dead a long time ago.
- Mental World: His combat ability is to enter a person's REM state to injure them physically by controlling their brain signals.
- Mirror Boss: The OVA filler had Meimu create a mirrored conscience of Teppei to go against Teppei to see if he can conquer his own growing strength.
- Redemption Equals Death
GaiThe last of the Demon Generals to appear. A philosopher, he originally was going to face-off with Teppei one-on-one since Teppei was the first to arrive at his stationed post, but Foh offered to take on Gai in Teppei's place in order to let Teppei enter the Empire Tower to search for his brother as soon as he can.
- Physical God: In the manga, Gai technically doesn't exist, is immortal, can make an infinite number of copies of himself, and has possibly unlimited firepower.
- The Power of Love: The only reason Foh was able to defeat Gai. note
- Nietzsche Wannabe: Gai is the philosopher of the empire, but also a firm believer that Humans Are the Real Monsters.
The Machine Empire
- Action Girl: Not only did she defeat the Juggler (who was giving Ron a very difficult battle) in one blow but she is rumored to have never lost a single battle and is infamous as a legendary warrior in her old life.
- Bifauxnen: Especially when she was a child. Ron thought she was a boy right on the get-go, and panicked as soon as he touched her chest while brawling with her.
- Clothing Damage: Misha throws her one in manga vol.9, leaving one of her girls exposed when she ticked him off asking for his permission to destroy B't Raffaello.
- Heroic Sacrifice
- Lady of War: She's a high-ranking Machine Empire General, and in fact the renowned and undefeated Rose Knight. During her tournament against Juggler, she struts her stuff and trounces him.
- My Country, Right or Wrong
- Sexier Alter Ego: In the anime.
- Shaking Her Hair Loose: To show she's getting dangerous.
- Shout-Out: To Zorro, because of her fencing skills and hidden badassery.
B't Rosemary the Queen Ant
- Cool Airship: She's big ass, really big ass.
- Deadly Gas: She took out a whole dome full of intellectuals to kidnap Professor Kotaro.
- Demoted to Extra: Her Donor got lots of screen time, but all she can do is to stay put in The Tower's parking lot...
- Minored In Ass Kicking: Given her Donor, Aramis' high military rank, technically she should be pretty badass. Sadly we never get to know the truth.
- We Hardly Knew Ye
- Blade Below the Shoulder
- Break the Haughty: Ever since Teppei knocked him out of his high chair, Metalface could never beat him up ever again.
- Cybernetics Eat Your Soul
- Heroic Sacrifice: He took Karen's place in obtaining The Piece of the Sun for her. He Disappears into Light upon handing it to Karen.
- Jerk with a Heart of Gold: Only to those who are on his side of the team...though.
- Pride Before a Fall
- Smug Snake
- Tsundere: He's not helping Karen just because he'd helped her since they were kids, but to prove to Teppei that he has guts...right.
B't Madonna the Triceratops
- All Girls Want Bad Boys: It's implied that she had fallen for X.
- What Is This Thing You Call "Love"?: She starts to ponder this after wondering how X can get along with Teppei so well despite being programmed with Undying Loyalty commands in their system.
- What Measure Is a Non-Cute?: For a female B't... but Teppei, she's a Triceratops for goodness sake!Teppei: "What!? She's a girl!?"
- Monster Clown: He gets better in the manga, however.
- Redemption Equals Death: In vol. 14 of the manga, Juggler performed his HeelFace Turn by opening the East Gate to the Central Tower to let Teppei in, and gave his one-and-only anti-bleeding pill to Teppei while he faces death by holding down the Ryukaon guards as much as he can so that Teppei can proceed to the Tower.
- Faceless Mooks: She was one of them until Teppei's intrusion to the Empire.
- MookFace Turn: She calls it quits fairly early within the storyline, then proceeds to spend the rest of the series taking care of the kids at Foh's orphanage.
- Separated at Birth: From her sister, Karen. Karen knows who Karin is, but Karin does not, because she has amnesia.
- Trauma-Induced Amnesia: Witnessing all of her elementary army school classmates get devoured by B't Raffaello in front of her eyes is too much for her poor soul.
- Filler Villain: Kaos plays an important role in coining the phrase "Buddy", which is used a lot in the remainder of the series, and furthering Teppei's Character Development.
- Must Make Amends: Marcelo does a lot of very, very stupid and amoral things, ultimately pushing him to strive to do everything he can to help Kotaro when that time comes. In the anime, his knowledge of the tower's layout is utterly crucial.
- Oh, Crap!: Gets a very nasty serving of this when Aramis tells him that Pr. Kotaro is to be well cared for, as he will eventually become a very important person for the Empire. He just pretty much had just sent him to die MINUTES before.
- Villainous Demotivator: Towards anyone whose ranks are lower than him in Underhell, and that's everyone down there.
- Because You Were Nice to Me: His response to Kotaro's kindness towards him, and he repays him greatly.
- Mistreatment-Induced Betrayal: He left Marcelo's side without even blinking an eye.
- The Power of Friendship
- Shock Collar: His Cybernetic body parts were poorly done, which makes him suffer from extreme pain.
- A Taste of the Lash: Marcelo whips Amigo whenever he doesn't obey his commands.
- You Shall Not Pass!: In the anime, Amigo guards over one of The Tower's computer room where Kotaro's attempting to hack in. When he's near his death, Amigo wraps his arms around the metal pipes surrounding the door with his body, which stalls the enemy mooks long enough for Teppei to arrive and finish them off.
Dr. Lisa Maria Stein
- Ascended Extra: She's an anime-original character, yet she's got bigger supporting status than original manga scientist characters.
- Promoted to Love Interest: To Kotaro.
- Yamato Nadeshiko: She's clearly this even though she's not Japanese.
- Ambiguously Brown: He's got a pretty tanned complexion, but it's justified that he's a Child Soldier who's stationed at a dessert area.
- Child Soldier: Implied to be forced into unauthorized military labor.
- Child Prodigy: Of robotic engineering. Gaku showcased his talents in building not-too-shabby Macross Missile Massacre robots out of scrap metal, but it's no way in comparison to the level of B'ts, and he doesn't have the resources to refine his talents. But Gaku is an example on how much advanced the common civilians of The Machine Empire are in terms of technology and engineering education.
The Machine Emperor
- Creepy Children: Both Misha and Nasha are 300 year-old children who stopped aging due to their Emperor granting them cybernetic bodies. While Nasha is shown to be mentally mature, Misha is psychotically childish.
The older brother of the twins. He abides by The Emperor's orders in the most absolute fashion, and rules his country with an iron fist. If anyone questions anything in regards to his authority and The Empire's orders, he would gleefully execute them on spot.
- All of the Other Reindeer: He got hit with this for his psychic powers even as a normal human.
- Cybernetics Eat Your Soul
- Deal with the Devil: When Nasha was dying from war injuries back in their day of The 16th Century, Misha was willing to trade anything for Nasha's cure. Since he knows praying to God won't help, he asked for the devil; and the devil that appeared was the Machine Emperor.
- Mind over Matter: Even before his deal with the Machine Emperor, and getting a cybernetic body, he already had psychic powers that set him apart from regular humans.
- Kick the Dog: He violently blows up a mooks head because he was a bit too insistently asking for orders.
- Knight Templar Big Brother: To Nasha.
- Really 300 Years Old
The younger sister of the twins. She is merciful and compassionate to her people compared to her brother, therefore, she would do all she can to veto her brother's immoral decisions. Nasha has poor health due to her cybernetic body, therefore, there's is little she can do to prevent her brother to place harm on civilians.
- All-Loving Hero
- The Chooser of The One
- Crucified Hero Shot: In the anime.
- Eyes Always Shut
- Expy: The Cutie Ill Girl version of Athena.
- The Heart
- Ill Girl
- Morality Chain: Of Misha.
- Princesses Prefer Pink
- Really 300 Years Old
- Telepathy: Due to her illness, she has to be in sleep mode for most of her life, whether she liked it or not. This led her to gradually develop the ability to send out her brain signals in a grand radius to watch over her countrymen, and enter to the Mental World of whomever she wants to speak with. Out of all the people she observed, she only connects to Misha and Teppei for mental communication.
- A God Am I
- Exposition of Immortality: He lets Misha in on his ambitions and secrets to immortality when he picked Misha and Nasha up from The Renaissance period.
- The Faceless: We do not see the Machine Emperor in "person" until the final volume, and never once in the anime. The final volume of the manga eventually reveals his physical body has been long dead, but his brain is instead enlarged and kept alive through machine technology, waiting to be placed into B't Raffaello, which was intended to become his "new body."
- Immortality Seeker: Amongst his vast bio-engineering creations, his greatest ambition was to create an immortal life-form of himself. Via merging with B't Raffaello.
- Insufferable Genius
- Persecuted Intellectuals: He was a scientist most likely born from the 1200s A.C. who proposed various mechanical engineering advancements to the people of his time, but was likely persecuted as a Mad Scientist. Leading him to despise all humanity, and attempting to become God himself.
- Time Abyss
- The Assimilator: Raphaello's shtick. It provides gallons of terror.
- Eldritch Abomination: Tentacles? Check. Mostly incapable of communication? Check. Mostly incomprehensible design? Check. Risks destroying the world? Check.
- Clipped-Wing Angel: In the manga, there is a lot of build-up to his final form, which looks actually less scarier than its incomplete form, since it looks like a giant Surplice from Saint Seiya and gets promptly defeated by Teppei via the Power of the Sun. The anime successfully averted this.
- Shape Shifter Mashup