The Character Sheet for the light novel series The Ending Chronicle.
Beware of Unmarked Spoilers.
The main protagonist. Sayama is the eccentric Taka-Akita Academy's Student Council vice-president. By the will of his deceased grandfather Kaoru Sayama, he was designated as the representative of Low-Gear in the Leviathan Road negotiations. He becomes Team Leviathan representative, negotiator and leader. He has been raised from childhood to be a superb villain to perform necessary evils.
Currently without any relatives, the Tamiya household takes care of him, but Sayama keeps distance from them because they only treat him with respect for a debt they own to his grandfather. He was trained by Ryuutetsu Hiba at the Hiba Dojo, so he is quite proficient at martial arts.
He is the user of Georgius, a mysterious glove that happens to be a Concept Weapon left behind by his mother.
- Ambiguous Disorder: Sayama is very serious, intelligent and skilled at what he does. He's also really weird, doesn't seem to understand social conventions in the least and always says and does things that get people uncomfortable without realizing. Despite all this, Sayama genuinely doesn't realize what is wrong with him and insists those around him are the ones with the problem.
- Anti-Hero: Sayama is certainly one of the good guys, yet he calls himself a villain who will resort to any dirty methods necessary to crush his enemies.
- Battle Couple: With Shinjou.
- Bunny-Ears Lawyer: Despite all his eccentricities, Sayama is a very sharp and skilled negotiator.
- Cassette Craze: He carries around portable recorders that he likes to use to record Shinjou saying Innocent Innuendos. He also has several recorder versions such as the indoor version, the outdoor version, the adventure version, happy version, demon king version, and more.
- Chivalrous Pervert: As much of a shameless pervert he can be to Shinjou, he does care about her well-being and feelings very much. Even though he's very open about wanting to have sex with her, he refrains himself from doing it until she grows accustomed with her own Sex Shifting body.
- Cloudcuckoolander: His thought process is really odd and hard to follow.
- The Comically Serious: He always keeps the same serious expression even in his most eccentric moments.
- Crazy-Prepared: Sayama seems to be prepared for any kind of situation he might encounter. He carries around a screwdriver, a wrench set, a set containing a stethoscope and portable recorder just in case. He also keeps underwear for Shinjou with him in case of an emergency.
- Crotch-Grab Sex Check: He makes sure that "Setsu" is a boy by grabbing and pulling his penis in the bathroom. Later, he undresses and grabs "Sadame"'s crotch to confirm she's a girl and not "Setsu" in disguise. Sayama fails to even see the possibility that Shinjou is a Gender Bender for quite some time, but he later figures it out.
- Cuckoosnarker: Sayama might have a very... peculiar way of thinking and behaving, but he's quick to make sarcastic quips at those around him. This is one of the first signs that he's much sharper than he may appear to be.
- Deadpan Snarker: He always takes the chance to make snarky comments about those around him.
- The Dulcinea Effect: He readily jumps to save Shinjou from a werewolf when he doesn't even know her yet.
- Genre Blind: Throughout the second arc, despite already knowing he lives in a world that keeps hidden survivors of alternate worlds, most of which are fantastic creatures like dragons, monsters and even gods, he completely fails to consider the possibility that Shinjou is a Gender Bender and both Sadame and Setsu until near the end of the arc.
- Guile Hero: He usually resorts to manipulation and blackmail to succeed in the Leviathan Road negotiations.
- Hilariously Abusive Childhood: Sayama's childhood involved him getting repeatedly beaten up and abused by his grandfather, as well as almost getting killed by his martial arts teacher multiple times. Of course, this is all Played for Laughs.
- Idiot Hero: Sayama is very intelligent, but his utter lack of common sense leads to him acting in pretty stupid ways that give him fame as an idiot.
- If It's You, It's Okay: Sayama says he's not into boys, unless that boy is Shinjou.
- Ill Boy: Every time he remembers his family he suffers from symptoms similar to an angina, causing severe pain that sometimes even forces him to his knees.
- It's All About Me: He calls himself the center of the universe.
- Innocently Insensitive: He really doesn't seem to realize just how rude and inappropriate he can be when he talks to people sometimes.
- Jerk with a Heart of Gold: He's arrogant, self-centered, rude, snarky and manipulative, but ultimately a good-natured and well-meaning guy.
- The Leader: A mix of the The Mastermind and Type Charismatic. He leads Team Leviathan in their negotiations and fights, makes most of the major decisions of what to do in the Leviathan Road and despite his general weirdness, he knows to give damn good motivational speeches for his team.
- Lovable Sex Maniac: A good part of Sayama's interactions with Shinjou have him making all sort of perverted remarks, particularly about her butt. He also likes to ogle at her, undress and grope her every chance he gets.
- Necessarily Evil: His grandfather raised him to be a villain who would perform necessary evils in order to destroy his evil enemies. However, Sayama doesn't know when the abilities he carries are truly necessary since his grandfather didn't teach him when to get serious.
- No Sense of Personal Space: He tends to get too uncomfortably touchy-feely around Shinjou.
- No Social Skills: He usually doesn't seem to understand what is proper to do when interacting with people, says things in a blunt manner at the worst possible moments and completely fails at reading the mood.
- Oblivious to His Own Description: Every time he's referred to as the eccentric, self-centered idiot he is, Sayama doesn't catch on they're talking about him. He's also perplexed when Shinjou says he's just like his grandfather, as Sayama thinks there's no way he's similar to that "self-centered old man who did nothing but eloquently mock others".
- Omniglot: He knows 13 different languages. His grandfather taught him.
- Only Sane Man: Subverted. He believes himself to be this, but he's really just as weird as everyone around him, if not more.
- Opposites Attract: With Shinjou. He's a sarcastic, arrogant Jerk with a Heart of Gold and she's a sweet, sensitive all-around Nice Girl. The very reason Sayama became attracted to her in the first place is because he views her as his polar opposite.
- Ordinary High-School Student: He lives as a rather normal high school student until he finds out about the Concept War and that his deceased grandfather left him the right to be the representative of Low-Gear in the negotiations for the Leviathan Road.
- Pragmatic Hero: Sayama was taught that in order to destroy evil, he would have to do some evil deeds himself and he frequently resorts to things like ruthless tactics and blackmail to defeat his enemies.
- Raised by Grandparents: He was raised by his adoptive grandfather after his parents died when he was young.
- Rude Hero, Nice Sidekick: The Rude Hero to Shinjou's Nice Sidekick. Sayama is a self-proclaimed villain who is willing to do some "evil" in order to defeat his enemies, not to mention he's also a self-centered jerk who enjoys to insult and mock those around him. His partner Shinjou, on the other hand, is so gentle and compassionate that she refuses to harm her enemies. In fact, Sayama chooses Shinjou as his partner because he's "wrong" and she's "right".
- Second Year Protagonist: He's a second-year high school student and the main character of the series.
- Sharp-Dressed Man: He likes to wear suits, so when not wearing the school uniform he usually wear a three-piece suit.
- Single-Target Sexuality: A rather blatant Shinjou-sexual. He feels equally attracted to her regardless of her being a girl or a boy.
- Skunk Stripe: He has a single white stripe on either side of his otherwise black hair.
- Sophisticated as Hell: He always speaks to people in a formal and polite manner with several insults and snarky comments mixed in.
- The Southpaw: He's left-handed.
- The Stoic: The expression on his face rarely changes, even in the most extreme and weird situations.
- Sugar-and-Ice Personality: He acts formal, aloof and distant in front of everyone. His sugary side seems to be reserved for Shinjou.
- Take a Third Option: When Shinjou asks him to either choose Sadame or Setsu, Sayama tells her he can't choose one of her false identities; instead he's choosing her real self, Sadagiri.
- Tsurime Eyes: His characteristic sharp eyes, a reflection of his arrogant and confident nature.
- Understanding Boyfriend: Shinjou at first feels conflicted about revealing the truth of her body to Sayama, because she fears Sayama will hate her if he finds out. Once the truth comes out, Sayama has no problem with Shinjou's Gender Bender condition; he loves Shinjou just for being Shinjou.
- Vitriolic Best Buds: With Izumo. They're pretty good friends, leaving aside their constant share of insults and snarking.
Sadagiri "Sadame, Setsu" Shinjou
A mysterious girl assigned to the Team Leviathan. She has lost her memory, so she does not remember where she came from or her own parents, so she joins the Leviathan Road to find information about her past. For some reason, her body changes sex from day to night, which is why she doesn't know from which Gear she comes from. To hide the special condition of her body, she lives alternatively under the identities of the twins Sadame and Setsu. Under the identity of her own twin brother, Shinjou soon becomes Sayama's roommate and later assumes the position of Taka-Akita Academy's Student Council secretary.
As a gunner, she uses the Cowling Staff Ex-St as her personal weapon. At Shinjou's request, Ex-St's attack power is proportional to the strength of her intentions, so it would not create more destruction than the user wished.
- Action Girl: As she adapts to the battlefield, she becomes an efficient gunner.
- Alliterative Name: Sadagiri Shinjou. It also applies for her false names Sadame and Setsu.
- Amnesiac Hero: She has no memories from before she was 6 years old. She joins the Leviathan Road to find information about her past and her parents. Her only clues are her name, a men's ring in her right hand's middle finger and the memory of the Silent Night song.
- Attractive Bent-Gender: Shinjou looks cute either as a girl or as a boy. Sayama especially finds her attractive in either form.
- Battle Couple: With Sayama.
- Bokukko: She uses the Japanese male pronoun boku to refer to herself. It's sort of justified since she's a boy during half of the day.
- Child of Two Worlds: Literally. Shinjou is the child of a Low-Gear woman and a Top-Gear man. To make it weirder, her parents were opposite-gender counterparts of each other.
- Cloudcuckoolander's Minder: She somehow puts up with Sayama's craziness and acts as a stopper for his eccentric actions.
- Country Mouse: Having grown up in the mountains of Okutama, Shinjou is quite clueless and naive about the modern life in the big city.
- Cry into Chest: She cries into Sayama's chest when she breaks down and tells him she doesn't want to keep lying to him, even though she fears he will hate her if she reveals her lie to him.
- Fake Twin Gambit: The twins Sadame and Setsu are identities she uses to hide her Gender Bender situation.
- Flower in Her Hair: After the negotiations with 4th-Gear are finished, Shinjou keeps the flower that contains the tree serpent Mukiti's will in her hair.
- Hair Color Dissonance: Her hair color is described as black in the light novels, but illustrations portray it as purplish blue.
- Involuntary Shapeshifter: Shinjou's body changes between male and female form at a half a day time. She has no control over the change and her body has been like that ever since she can remember.
- The Lancer: She backs up Sayama at all times and as his opposite, she naturally acts as his foil.
- Male Gaze: Sayama finds Shinjou's butt rather "eroundic".
- Meaningful Name: Shinjou's real name Sadagiri means "cut life from destiny". Shinjou doesn't like it since she thinks it's a bad omen, but Sayama convinces her that her name's real meaning is to "cut away the bonds of destiny, freeing life".
- Mistaken for Gay: A Running Gag with her and Sayama. Shinjou is only known as "Setsu" at school and thanks to her clearly close relationship with Sayama coupled with being caught in some suggestive situations, they have gained a reputation as a "hardcore gay couple" across the campus.
- Morality Chain: Part of her role as Sayama's counterbalance. Sayama wants her to keep him from taking his evil too far and let him know when his evil is truly necessary.
- Most Writers Are Writers: She wants to be a writer and she's writing a novel based on the events of the series.
- Ms. Fanservice: The story never misses the chance to show Shinjou's skin, no matter if it's her female or male form.
- Naïve Newcomer: Shinjou had never fought at the front lines until she joined Team Leviathan. Her lack of experience and naivete gives her great trouble.
- Necktie Leash: She usually strangles Sayama with his own tie when he gets her annoyed.
- Nice Girl: Sweet, polite and selfless.
- No Periods, Period: Shinjou mentions she hasn't had her period yet. Sayama thinks it may have something to do with her reluctance to accept her sex-changing body and he suggests her to try and accept it the way it is so it can properly develop.
- Opposites Attract: With Sayama. She's a sweet, sensitive all-around Nice Girl and he's a sarcastic, arrogant Jerk with a Heart of Gold.
- Rapunzel Hair: She has waist-lenght hair.
- Reluctant Fanservice Girl: To her dismay and embarrassment, she usually ends up losing her clothes or getting into awkward situations with Sayama.
- Reluctant Warrior: She really hates fighting. She only joined Team Leviathan to find out about her past.
- Rude Hero, Nice Sidekick: The Nice Sidekick to Sayama's Rude Hero. As Sayama's counterbalance, the gentle Shinjou represents the "good" that keeps the self-proclaimed villain Sayama from taking his "evil" too far and bring out the best of him.
- Sex Shifter: Shinjou's body changes sex from day to night; she's a boy during the day and a girl during the night.
- Skilled, but Naïve: It's said Shinjou had excellent scores in training and her marksmanship while providing covering fire from the rear guard was good, but when put to fight in the front lines as a member of the Team Leviathan, Shinjou's inexperience and reluctance to fight keeps her from doing a good job.
- Small Girl, Big Gun: Her Cowling Staff Ex-St can morph into a large cannon.
- Sobriquet Sex Switch: She goes by Sadame when she's a girl and by Setsu when she's a boy. These names are made from the characters of her real name, Sadagiri. Sadame is written like Sada (運) and Setsu is written like Giri (切).
- Straight Man: She usually takes this role by being the one to tolerate Sayama's craziness and call him out on the stupid things he does.
- Strong Family Resemblance: She looks identical to her mother, Yukio Shinjou.
- Tareme Eyes: Her eyes are big and round, reflecting her sweetness and naivety.
- Transgender Fetishization: Despite her body's recurrent Sex Shifting, Shinjou is still the source of most of the Fanservice in the series, coming with several nude scenes no matter if she's "Sadame" or "Setsu" at the moment.
- Tsundere: A mild Type B. She's an all-around Nice Girl, but is far more likely to get annoyed around Sayama.
- You Gotta Have Blue Hair: Purplish blue, to be exact. Although it's supposed to be black.
Taka-Akita Academy's Student Council president and Team Leviathan vanguard force along with his partner Chisato Kazami, who is also his girlfriend. An irresponsible and cheerful individual. He is the son of the current president of IAI and a goddess of 10th-Gear.
His main weapon in combat is the Cowling Sword V-Sw, which has the 6th-Gear Concept Core sealed inside.
- Badass Longcoat: He wears a longcoat as part of his UCAT uniform.
- Battle Couple: With Chisato. Together they form the Team Leviathan vanguard force.
- Beta Couple: With Chisato.
- BFS: He wields V-Sw, an unconventional enormous Cowling Sword.
- The Big Guy: He's the largest member of Team Leviathan, in terms of size of both his body and his weapon and personality.
- Child of Two Worlds: Quite literally, as he's the son of a man of Low-Gear and a woman of 10th-Gear.
- First-Name Basis: He and Kazami call each other by name.
- Henpecked Husband: He and Kazami are not actually married yet, but she surely has him whipped already. Kazami is even labelled his "violent controlling wife".
- The Illegible: Sayama compares Izumo's handwriting to "the death throes of an earthworm suffering from a twisted intestine". Ironically, his awful calligraphy is the most effective in a 1st-Gear Concept Space.
- Like an Old Married Couple: With Chisato.
- Man, I Feel Like a Woman: When he and Chisato swap bodies, Kaku takes the opportunity to grope her breasts. He also says he took the liberty to do some "important research".
- Semi-Divine: He is the son of a Low-Gear human and 10th-Gear goddess, so he is a Low-Gear and 10th-Gear mixed race that has inherited divine protection from his mother.
- Student Council President: He is supposed to be this, but he hardly takes his position seriously.
- Vitriolic Best Buds: With Sayama.
Taka-Akita Academy's Student Council treasurer and Kaku Izumo's girlfriend who lives with him in the Academy's dorms. She's part of Team Leviathan vanguard force along with her boyfriend. Originally she was a Low-Gear ordinary person, but after the Leviathan Road with 6th-Gear and 10th-Gear two years before the story began she became a member of the Japanese UCAT.
Her main weapon is G-Sp2, a Cowling Lance that holds inside 10th-Gear's Concept Core. She also uses the Concept Equipment X-Wi, producing yellow wings of light who lets her to leapt high into the sky and fly across the battlefield, giving her high mobility.
- Action Girl: She stands out as the only female close-range fighter in Team Leviathan.
- Battle Couple: With Kaku. She's his girlfriend and partner in the vanguard force.
- Beta Couple: With Kaku.
- Blade on a Stick: Her main weapon G-Sp2 is a Cowling Lance.
- Fashionable Asymmetry: She wears one normal fingerless glove and an elbow-length one in her UCAT uniform.
- Florence Nightingale Effect: She first met Kaku when she found him and took him in after he was attacked by a group from 6th-Gear. Although Kaku says she wasn't the best nurse as she threw him in a wax storage room and forgot about him for half a day.
- Goggles Do Nothing: She always sports a pair of goggles on her head without practical purpose.
- Like an Old Married Couple: With Kaku.
- Only Sane Woman: Within a Team Leviathan full of eccentric individuals, she is the one of the most grounded in common sense.
- Power Gives You Wings: She uses the Concept Equipment X-Wi, which produces yellow wings of light to let her to leapt high into the sky and fly across the battlefield.
- Steven Ulysses Perhero: Kazami means "weathervane", relating to her power to bring out wings to fly. As Sayama says, "she has the power to live up to her name".
- Tsundere: While she clearly loves her boyfriend, she smacks him around whenever he acts like a perverted idiot.
An underclassman who happens to be deeply involved with the situation of 3rd-Gear. He is the grandson of Ryuutetsu Hiba, the one who destroyed 3rd-Gear. Ryuuji says 3rd-Gear is tainted by an impurity he must cleanse before handing the Concept Core to Team Leviathan. He wants to obtain the other half of 3rd-Gear's Concept Core because he believes with it Mikage's evolution into human will resume its course.
Along with his automaton partner Mikage, Ryuuji pilots the God of War Susamikado, which houses part of the 3rd-Gear Concept Core inside the Concept Weapon Keravnos.
- Battle Couple: With Mikage.
- Cain and Abel: The Abel to Tatsumi's Cain. He once viewed her as his sister, but now she has joined the Army and has full intent to fight him as a member of UCAT.
- The Caretaker: Due to the lack of mobility of Mikage's body, Ryuuji is the one who takes care of almost everything for her, such as carrying her around, pushing her wheelchair and helping her wash her body in the bath. He also gives her speech training by reading her journal entry aloud and have her move her mouth to emulate his.
- Covert Pervert: He tries to be quiet about it, but he's as much of a pervert as Sayama and Izumo. He especially shows it when under the effect of the interrogation device Shameful 2000.
- Early-Bird Cameo: He appears briefly in the second arc when he goes to visit his grandfather's dojo to take some pickled vegetables for his "girlfriend".
- Family Theme Naming: Ryuuji Hiba, son of Ryuuichi Hiba and grandson of Ryuutetsu Hiba.
- Martial Arts Headband: He usually wears a white headband around his head.
- Nice Guy: A very kind-hearted and polite boy.
- Red Eyes, Take Warning: Subverted. He has red eyes, but is an all-around Nice Guy.
- Robosexual: He has very obvious feelings for his automaton partner, Mikage. Although, he fell in love with her knowing she will eventually become a human like him.
- Scars Are Forever: He has a scar running in a diagonal line along his forehead.
Ryuuji's automaton partner. Originally a human being, Mikage is the youngest child of the last king of 3rd-Gear, Zeus. Before she was born, Zeus planned to use Mikage for a cloning program to increase the population of 3rd-Gear. To protect her child, Mikage's mother Rhea betrayed 3rd-Gear and fled to Low-Gear. However, Mikage was abducted by Zeus and Apollo shortly after her birth. Since Mikage's body would grow into one that could not bear children, her grandfather Cronus transferred her into the body of an automaton that would evolve into a human able to have children. However, the evolution of Mikage's body stopped five years ago for some reason. She was left in the care of the Hiba family by Ryuuji's father shortly before he died ten years before the start of the series, which allowed her to become very close to Ryuuji.
Initially, Mikage's automaton body doesn't function well; she can't walk nor even speak, but she can move a little thanks to the philosopher's stone inserted in her body. Later on, as her body resumes its evolution, Mikage's physical capacities improve.
Along with Ryuuji, she pilots the God of War Susamikado, which houses part of the 3rd-Gear Concept Core inside the Concept Weapon Keravnos.
- Artificial Human: Played with. Mikage originally was a naturally-born human, but she was transferred into an automaton body shortly after her birth. Her robotic body slowly evolves into a real human being.
- Battle Couple: With Ryuuji.
- Become a Real Boy: She's an automaton that slowly evolves into a complete human being.
- Cute Mute: Initially, Mikage's vocal cords are still immature, so she can't talk unless she's combined with Ryuuji in Susamikado. As her body evolves, she gains the ability to speak normally outside Susamikado.
- Disabled Love Interest: To Ryuuji. Mikage can't move her arms and legs properly and she also can't talk. Ryuuji is clearly in love with her and is always there to take care of her. After gaining the ability to stand and walk on her own, Mikage does her best to not be a burden for Ryuuji anymore.
- Emergent Human: Mikage is a special automaton programmed to slowly evolve into a human being. As her evolution progresses and Mikage learns more about the world and being human, she gains more control of her body and starts to understand emotions.
- Hair Color Dissonance: After her evolution into a human being is completed, the light novel describes Mikage's new hair color as black, but it looks closer to dark blue in colored illustrations.
- Hair of Gold, Heart of Gold: She has long blonde hair and she's very kind-hearted and innocent.
- Innocent Fanservice Girl: She doesn't understand what Ryuuji gets so flustered when he washes her body in the bath.
- Locked into Strangeness: As her evolution into a human being is completed, Mikage's blonde hair turns dark blue/black.
- Meaningful Name: Mikage means "beautiful shadow". When Mikage was born, her mother saw the early morning scenery and she thought it warranted that name for her daughter. Since 3rd-Gear didn't have that, she gave her that name to remind Mikage that she was a child of Low-Gear.
- Multicolored Hair: She has blonde hair with blue highlights at the end. As she evolves into a full human being, it turns completely dark blue/black.
- Odd Name Out: Mikage is the only character from 3rd-Gear that doesn't have a name related to Greek mythology. Justified, since her mother wanted her to have a Low-Gear name.
- Psychosomatic Superpower Outage: The real reason Mikage's evolution stopped was her own fear of becoming human and how it might affect her relationship with Ryuuji. Once she overcomes those fears, her body starts to evolve again.
- Rapunzel Hair: She has very long hair that goes past her hips.
- Robot Girl: An automaton with the appearance of a young girl.
- Silent Bob: Ryuuji can communicate with her despite her not being able to talk. He can even have phone conversations with her because he can get an idea of what she's thinking.
- Single Woman Seeks Good Man: She has feelings for Ryuuji, who is a kind-hearted boy and always does nice things for her.
- Skunk Stripe: As her evolution into a human being is completed, Mikage's hair turns almost completely dark blue/black, with only a single blonde stripe remaining.
- Speech-Impeded Love Interest: Mikage's immature vocal cords don't allow her to speak clearly, so she can only communicate with Ryuuji through lip movements and her journal. He also tries to help her with it by giving her speech training.
- Throwing Off the Disability: As her body continues to evolve into human, Mikage gains the ability to freely move, walk and talk on her own.
- The Unintelligible: At first, Mikage can only mutter unintelligible sounds that can only be understood through lip movements. After her vocal cords evolve, she can speak intelligible words.
A Japanese-American student from Sayama's class who has a reputation as a delinquent due to frequently skipping class and rarely showing up at school. He has a part-time job at the Yokota Air Base and is currently living alone in an apartment due to his father dying in the Great Kansai Earthquake and his mother being hospitalized because of an illness she got when helping with that earthquake. He becomes involved in the Leviathan Road when he finds and takes in Heo Thunderson when she's running away from the 5th-Gear black mechanical dragon Black Sun. He soon decides to join the fight in order to protect Heo.
He's in charge of piloting the mechanical dragon Thunder Fellow, the last of the mechanical dragons of 5th-Gear which was entrusted to Heo.
- Accidental Pervert: He repeatedly ends up in situations where he accidentally sees Heo naked and such.
- Battle Couple: With Heo.
- Bookworm: He loves to read books and secretly wishes to open a bookstore one day.
- Chekhov's Gunman: He makes short, not much relevant appearances in early arcs. It's until the fourth arc when he finally becomes involved in the story and reveals his important role.
- Cool Shades: He always wears sunglasses.
- The Dulcinea Effect: He decides to risk his life in order to protect a girl he has known for a couple of days.
- Full-Name Basis: He usually calls others by their full name. The only exception is when he occasionally calls Heo by her first name.
- Japanese Delinquent: He's always skipping class and drinks beer when he's underage.
- Jerk with a Heart of Gold: He may appear to be rough, moody and rude, but he's a nice and protective person.
- Minor Living Alone: He's a second-year high school student living in an apartment on his own because to his father is dead and his mother is hospitalized. Later, Heo goes to live with him.
- Nom de Mom: He uses his mother's surname Harakawa instead of his father's surname Northwind due to his resentment towards his father.
- One Head Taller: He tops Heo's height by a full head.
- Opposites Attract: With Heo.
A middle school student from America and the great-granddaughter of Richard Thunderson, the one responsible for the destruction of 5th-Gear. She came to Japan with her great-grandfather to cooperate in the Leviathan Road with 5th-Gear, but when they arrive they are attacked by the 5th-Gear black mechanical dragon Black Sun. Richard tells Heo to run away while he stays behind to challenge Black Sun and is killed by it. During her fled, Heo passes out in front of Dan Harakawa's apartment and is taken in by him.
With her great-grandfather's death, Heo later assumes the position of 5th-Gear's representative. She's entrusted with the last of the mechanical dragons of 5th-Gear created from Richard's companion Xolotl 3, which she names Thunder Fellow. In battle, she supports Harakawa's piloting skills by using her mind to release the limiters of Thunder Fellow's body.
- Animal Motifs: She's frequently compared to a cat.
- Battle Couple: With Harakawa.
- Meaningful Name: Her name means "happiness" in 5th-Gear's language.
- Opposites Attract: With Harakawa.
- Raised by Grandparents: After both her parents died, she was raised by her adoptive great-grandfather.
- Reluctant Fanservice Girl: She repeatedly finds herself in embarrassing situations where she ends up naked and Harakawa is there to see her.
- Shrouded in Myth: When she was young, Heo's mother was killed by Black Sun and everyone who saw it thought it was a demon. After that, Heo and her great-grandfather moved several times and everywhere they went, the story of Heo's mother's death would get out and she would be known as the girl saved from a demon attack. She went from being the girl protected by god to being loved by a demon and sometimes she was said to be on the run after killing the people of her old town. Heo had a very hard time because of those rumors.
- Synchronization: In battle, Heo has to synchronize her senses with Thunder Fellow so she can control its limiters.
- Tragic Keepsake: She has a philosopher's stone necklace that she got from her deceased mother.
The head of Japanese UCAT.
- Big Good: He's the head of Japanese UCAT, the secret organization in charge of handling the survivors of the destroyed Gears and save the world from letting its own negative concepts destroy it.
- Butt-Monkey: He gets zero respect from his subordinates and he often ends up as the butt of the joke and target of slapstick.
- Character Tic: Thumbs-up.
- Dirty Old Man: The walls in his room are covered in posters of lewd girls and his hobbies include collecting erotic figures and photos of beautiful women as well as playing eroges.
- Idiot Hair: He has a long cowlick that stands prominently atop his head.
- Meaningful Name: Kazuo contains the kanji for 1. His father gave him that name because he wanted him to be #1 in everything.
- Mr. Exposition: He explains to Sayama and the reader about the other Gears, the Concept War and the Leviathan Road.
- Wacky Parent, Serious Child: He is a complete goofball, while his son Itaru is more serious and usually tries to straighten him up the hard way.
The son of Kazuo and the supervisor of Team Leviathan.
- Cool Shades: He wears a pair of sunglasses.
- The Gadfly: He tries to get reactions out of Sf with no success.
- Jerkass: He's not a pleasant person to be around, to say the least. It's most notable in his interactions with Sayama, his own father and Sf.
- Mr. Exposition: He gives expositions to the reader occasionally, usually through conversations with Sf about the Gears.
- Trash of the Titans: His office has books, documents, cardboard boxes, and packaging piled up all across the floor.
- Wacky Parent, Serious Child: Way more serious and brooding than his perverted goofball of a father. It's usually Itaru's job to try and straighten him up the hard way.
Itaru's personal maid and an automaton created by German UCAT using 3rd-Gear technology.
- Action Girl: A very formidable fighter, especially when it comes to protecting her master.
- Adorkable: She keeps a point card to score points for herself every time she does a good job for her master. Once she reaches 20 points, she praises herself by rubbing her own head.
- Badass Boast:"I was created for the sake of my master. I sacrifice my steel for his bones, my chains for his flesh, my oil for his blood, and my determination for his heart. But there is one thing he has for which I have nothing to sacrifice. His tears... As I have no emotions, I have nothing to give in return for those. As such, I do not desire my master's tears. I desire only an outcome that requires no teardrops."
- The Bore: Itaru finds her extremely boring due to her emotionless nature.
- The Comically Serious: The reason it's so damn funny that an emotionless robot once read out loud a pornographic manga Itaru handed her as a prank. She only complains her lack of emotion leaves her ill-suited for a text with so much shouting and so many sound effects.
- Emotionless Girl: As an automaton, Sf lacks emotions.
- Feel No Pain: When Sayama asks her if she feels pain when she loses an arm, Sf says she has no sense of pain. The only pain she can feel is from being unable to remain by Itaru's side.
- Germanic Efficiency: She claims that since she was created by German people, the "most excellent people in the world", her technology and combat abilities are top notch.
- Gravity Master: As standard from automatons, Sf can control gravity.
- The Gunslinger: She uses machine guns as her main weapon in combat.
- My Name Is Inigo Montoya:"My name is Sein Frau, 'the woman who should exist'. I am a nonhuman who was born from the desire to 'exist'. Now, come and bring the reason for your birth with you. If that reason is weaker than mine, you will not even be able to 'exist'."
- Mystical White Hair: An automaton with silver hair, which hints at her artificial origins.
- Ninja Maid: She was created to be Itaru's maid and was equipped with top combat skills to protect her master.
- Rei Ayanami Expy: A Robot Girl with short silver hair who lacks emotions and serves as the loyal servant of her master.
- Robot Girl: She's an automaton with the apperance of a young woman.
- Robot Maid: An automaton whose main function is to serve as Itaru's personal maid.
- Robot Names: Sf, which is a shortened form of her full name "Sein Frau".
- Trouser Space: She keeps weapons under her skirt using gravity control. She can even take out a Gatling gun from down there."How did you fit something so large under your skirt!?"
- Undying Loyalty: Extremely loyal and devoted to her master.
Sayama's homeroom teacher and English teacher, and Takaakita Academy's Student Council's adviser. Beneath that, Ooki is a 10th-Gear tree spirit who forms part of Team Leviathan as the one who handles the controllers for Concept Spaces.
- Cloudcuckoolander: Ooki is very weird and seems live in her own world.
- Cute Clumsy Girl: Extremely clumsy and careless. She's always late for class, often forgets her textbook, gets off the train at the wrong station, and cannot read what she herself wrote on the board.
- The Ditz: Very ditzy, absentminded and forgetful. Sayama likes to call her out on her foolishness.
- Genki Girl: She has a very cheerful and energetic personality.
- Idiot Hair: She has a cowlick that sticks straight up from her head. It highlights her ditzy and childish personality.
- Nature Spirit: She is a tree spirit from 10th-Gear.
- Not a Morning Person: She always has trouble getting up in the morning and she's usually late for her class because of it.
- Plucky Comic Relief: Every time she appears is mainly to bring comic relief to the scene.
- Pointy Ears: She has long elf-like ears to show her nature as a tree spirit. She keeps them hidden when she works as a teacher.
- Secret Secret-Keeper: She admits she figured out the Shinjou twins were one and the same from the beginning, but she kept it to herself.
- Sensei-chan: She's young, rather inexperienced as a teacher, cute and very childish. Her own students usually treat her like a child.
- Womanchild: She acts way more immature than her students. One time, she actually starts crying like a little kid when her forehead slams into a table.
The medical chief of Japanese UCAT. In the past, she belonged to Chinese UCAT and was the Eight Great Dragon Kings member in charge of 7th-Gear.
- Anime Chinese Girl: She's a (seemingly) young Chinese girl who wears a qipao and has her hair in a pair of odango.
- Odango Hair: She has two bun covers on either side of her head, as expected from an Anime Chinese Girl.
- Older Than She Looks: She looks like a young girl, but she's actually an old woman who has used a philosopher's stone to remain young.
A member of German UCAT and Siegfried's niece who was sent to Japan as European UCAT's inspector for Team Leviathan. She is also Germanys greatest witch who was once known as the Mother Cat and is the only surviving member of the Five Great Peaks. She was the teacher of Heo Thunderson and is the wife of Colonel Odor from American UCAT.
- Action Girl: Shortly after her introduction, she gives Brunhild a hard time in a duel in which Diana wasn't serious in the first place and then she kicks Izumo's and Sayama's asses in training. She's not known as Germanys greatest witch for nothing.
- Battle Couple: With Odor.
- Hot Witch: Known as Germanys greatest witch and she makes sure to look young and attractive for her age.
- Mystical White Hair: A witch with silver hair.
- Older Than She Looks: Thanks to a philosopher's stone, she looks like she's in her twenties when she's actually much older.
- Red Baron: Mother Cat.
- Sitcom Arch-Nemesis: With Brunhild. Always they are together, they are figthing or arguing about which of them is the stronger witch.
- Vain Sorceress: A witch who used a philosophers stone to make herself look young.
The inspector of American UCAT. After Richard Thunderson's death, he comes to Japan to protect Heo Thunderson and demand Japanese UCAT to pass the rights of the Leviathan Road to them. He is the husband of Diana Zonburg.
- All of the Other Reindeer: He says that in his youth, he was something no one wanted around and to be avoided to everyone around him. That's why he was given the nickname Odor.
- Badass Fingersnap: His main attack is a fingersnap that can crush his opponents to the ground.
- Badass Grandpa: He's pretty tough for a man of his age.
- Battle Couple: With Diana.
- Big Ol' Eyebrows: He has very thick eyebrows.
- Long-Lost Relative: He's Richard Davis, Heo's long-lost great-uncle.
- Only Known by Their Nickname: "Odor" is a nickname given to him by the people who abused him in his youth. His real name is Richard Davis.
- Scars Are Forever: His entire right arm is covered in countless overlapping scars and swellings. He says he got them in his childhood by people who treated him like a pest.
- Sympathetic Inspector Antagonist: He comes to try and take the rights of the Leviathan Road from Japanese UCAT, starting a small war between their factions. While his methods are very forceful and extreme, it's hard to not think he's kind of right about Japanese UCAT being incompetent and unfit for a job that has the fate of the entire world at risk when they couldn't even protect a single important figure like Richard Thunderson. Having someone like Sayama in charge of the negotiations that will decide the fate of the world also doesn't seem a reliable idea...
- Verbal Tic: He has a habit of repeating the first word of his sentences twice.
The librarian of Kinugasa Library at Takaakita Academy. He makes investigation concerning the Concept War on UCAT's behalf. During the Concept War, he was responsible for the destruction of 1st-Gear.
- The Atoner: He says he wishes to atone for his past crimes against 1st-Gear.
- Badass Beard: He has a beard only to emphasize his badassness.
- Badass Grandpa: His age doesn't stop him from joining the battle against the City faction.
- Badass Longcoat: He wears a black longcoat in battle.
- Bald of Awesome: He's bald, also an awesome fighter and when it comes down to it, a very nice man.
- Heartbroken Badass: The death of Princess Gutrune still fills him with pain and guilt.
- I Let Gwen Stacy Die: Princess Gutrune was mortally wounded protecting him from a berserk Fafnir. This is a source of sorrow and regret for Siegfried to this day.
- Silent Scapegoat: He willingly took all the blame for the destruction of 1st-Gear and let the survivors hate him because he believed it was for the best that they hated an outsider instead of letting them know their king was the real responsible for the destruction of their world.
- Take a Third Option: Shortly before the battle between UCAT and 1st-Gear's City faction, Brunhild asks Siegfried to take care of her pet bird to see if he chooses to stay to take care of the bird or to abandon the bird to join the battle. What does Siegfried do? He goes to the battle anyway, but he takes the bird with him.
A third year student and the head of the general art club at Takaakita Academy. In reality, she is a long-lived witch from the City faction of 1st-Gear who was assigned to an undercover mission to monitor Siegfried. She has a past with Siegfried.
- Action Girl: She's one of the strongest enemies in the City faction. Even without Requiem Sense, she's a very competent magic user.
- All Witches Have Cats: She has a black cat Familiar.
- Broken Bird: The destruction of 1st-Gear and the apparent betrayal of Siegfried toward her and Gutrune has left her bitter.
- Compulsory School Age: Despite her actual age, her teenage appearance allows her to easily pass off as a highschool girl. She keeps going to school even after the City faction is defeated and she doesn't need to monitor Siegfried anymore.
- Cry Cute: She breaks down in tears when Siegfried saves her from the Grim Reaper she created with Requiem Sense and she realizes he didn't abandon the bird she asked him to take care of.
- Cute Witch: A cute young-looking witch, complete with a cat familiar and a Flying Broomstick.
- Friend to All Living Things: She has a soft spot for animals, especially birds. She adopts a little bird that quickly becomes very attached to her.
- Girlish Pigtails: She has her long hair tied into two twin tails.
- Hair Color Dissonance: Her hair is described as platinum blonde or gray in the novel, but it looks closer to pale green in illustrations.
- Hair Decorations: The ribbons she uses to tie up her twintails.
- HeelFace Turn: She starts out as an enemy, being a member of the radical City faction of 1st-Gear. After the City faction is defeated, she becomes an ally of UCAT and helps the heroes several times.
- Long-Lived: She is part of a long-lived race from 1st-Gear.
- Older Than She Looks: While she looks like a teenage girl, Brunhild was alive during the Concept War sixty years ago.
- Parental Abandonment: Her parents died during the Concept War.
- Proper Tights with a Skirt: She wears black tights with her school uniform.
- Rapunzel Hair: Her twintails reach down to her knees.
- Robe and Wizard Hat: She occasionally wears a robe and a three-cornered hat.
- Sinister Scythe: Her main weapon is Requiem Sense, a giant scythe that stores the souls it hears and is essentially the underworld itself. With it, Brunhild can summon souls of the underworld and use them in battle.
- The Stoic: She usually keeps an expressionless face, but there are moments her emotions shine through.
- Sugar-and-Ice Personality: She appears to be stoic, cold-hearted and stern, but there are times she shows a softer and sensitive side.
- You Gotta Have Blue Hair: She has pale green hair in illustrations, although it's described as platinum blonde/gray in the novel.
A member of the Japanese UCAT's development department who is a descendant of the family of best swordsmiths of 2nd-Gear. He has been chosen as the representative of 2nd-Gear in the Leviathan Road, but he feels troubled about accepting the position since an incident eight years prior to the series made him reluctant to accept his relation to 2nd-Gear. He is happily married to a woman named Natsu and they had a daughter recently, however hiding the truth of 2nd-Gear, UCAT and an unfortunate accident he caused from his wife gives him much conflict.
- Afraid of Their Own Strength: He sealed his power to create swords after he caused a landslide accident from testing one of his swords. Since then, he has been too afraid that his power might hurt people again.
- The Atoner: He wants to make his wife and daughter happy to atone for causing the accident that nearly killed Natsu and made her lose two fingers.
- The Blacksmith: Bearing the name of the sword god of Japanese mythology, Kashima can create very powerful swords. However, he quit swordsmithing after the accident he caused eight years ago.
- Child of Two Worlds: He's a descendant of 2nd-Gear, but he was born and raised on Low-Gear. His struggle to accept himself as part of both worlds is one of the main points of his character arc.
- Doting Parent: He's constantly watching pictures and videos of his baby daughter Harumi and showing them to people.
- Happily Married: To Natsu, who he loves deeply. However, his guilt over the truths he must hide from her, especially the one of the accident make things difficult for their marriage.
- My Greatest Failure: The landslide accident he caused when he was testing one of his swords still haunts him. Especially since his wife was badly injured in the accident.
Akio Kashima's devoted wife. An ordinary Low-Gear human, she doesn't know anything about his real job at UCAT, but she acts as supportive of her husband as she can. She hates rain because it reminds her of an accident in which she lost two fingers of her left hand.
- Fingore: She lost two fingers of her left hand in an accident years before the start of the series.
- Good Parents: A very loving mother to her newborn daughter Harumi.
- Happily Married: She loves her husband very much and tries to support him in every way she can, even though she doesn't know the truth behind his job and other things.
- Hidden Depths: While she seems like the perfect wife, Natsu has issues of her own. She admits to Akio she keeps secrets from him and lies often, so he shouldn't feel guilty over lying to her all the time.
- Housewife: She devotes herself to take care of her family and their home.
- Hyper-Awareness: According to Kashima, Natsu can identify people just by their footsteps.
- Locked Out of the Loop: She doesn't know the truth of her husband's job at UCAT, his relation to 2nd-Gear or the fact that he was the one who caused the landslide accident in which she nearly died.
- Tragic Dropout: She dropped out of college after being traumatized by the accident in which she almost died.
- Trauma Button: Rain reminds her of the accident in which she nearly died.
Another descendant of 2nd-Gear and a close friend of Kashima. He was classmates with Ryouko Tamiya back in highschool and he has had an unrequited crush on her for years.
- Blood Knight: He loves fighting and is always eager to pick a fight.
- Delinquent Hair: He has dyed blond hair.
- Hopeless Suitor: To Ryouko Tamiya. He has loved her since they were in highschool, but she's completely oblivious to his feelings and only seems to be interested in the Sayama men.
- Jerk with a Heart of Gold: He may be rude and violent, but he's a good friend to Kashima and he also cares a lot about his highschool crush Ryouko.
The director of the Japanese UCAT's development department and bearer of the name of the imperial family of 2nd-Gear.
- Lunacy: As the bearer of the name Tsukuyomi, she has the power to control moonlight. In combat, she can throw hundreds of arrows of moonlight at her opponents.
- Never Mess with Granny: She can put a good fight for someone of her age.
- Widow Woman: Her husband supposedly died as a secondary casualty of the great Kansai earthquake at the end of 1995. However, she has always suspected there was something else behind his death.
The rebellious daughter of the director of the development department Shizuru Tsukuyomi. Although she's a pure-blooded 2nd-Gear descendant, Miyako has no knowledge of her mother's real job at UCAT or the other Gears. After being rejected at a job interview, she gets caught in the middle of a battle between Typhon and Susamikado and she gets abducted by Typhon. After being taken "hostage", she is welcomed like a princess by the automaton maids at the mansion of the 3rd-Gear base. She soon takes an interest in their master Apollo.
- Aggressive Submissive: She is tough and assertive most of the time, but when she has sex with Apollo she becomes very shy and flustered.
- Birds of a Feather: She becomes interested in Apollo as she sees herself reflected in him, both in terms of their similar situations and having lost their fathers.
- Former Teen Rebel: She was a delinquent in her teenage years. She has mostly reformed, but she still has a rebellious streak in her.
- Hair Color Dissonance: Her hair looks brown in illustrations, but it's described as black in the novel.
- I Will Wait for You: After Apollo is left comatose while his body recomposition takes time to stabilize, Miyako is told he will return "eventually". Miyako knows it could take thousands of years and she will probably never see him again, but she still decides to always be waiting for his return.
- Law of Inverse Fertility: She wasn't expecting to get pregnant from having sex with Apollo only one time, especially when it was Their First Time.
- Locked Out of the Loop: Her mother hasn't told her anything about her real job, the other Gears or her own 2nd-Gear blood. Miyako only gets to know about the Gears and the Concept War after she's abducted by Typhon.
- MayflyDecember Romance: With Apollo. He has likely lived for thousands of years while she's a regular human of college age.
- Meaningful Name: Miyako means "capital city". Her father had given her that name so that a great amount of people would gather around her.
- A Mother to Her Men: Once she takes leadership over 3rd-Gear's automatons, Miyako shows to care about them and treats all them as if they were people instead of machines.
- Rebellious Spirit: She always feels the urge to do the opposite she's told to do.
- Stockholm Syndrome: She becomes fond of her captors after Typhon kidnaps her and brings her to the 3rd-Gear base. It goes to the point she refuses to leave when given the chance and falls in love with Apollo.
- Tsundere: To Apollo. She calls him an idiot and can treat him harshly, but she can't deny her attraction to him. She is even tsundere in bed.
The last living 3rd-Gear human, son of Zeus and current king of 3rd-Gear.
- Birds of a Feather: With Miyako.
- Came Back Wrong: Apollo was originally killed by Susamikado during the Concept War. In order to revive him, Artemis overwrote his death with her life, but the split and re-composition were imperfect so Apollo ended up synchronized with Typhon which is now controlled by Artemis' soul.
- Convenient Coma: During the final battle against 3rd-Gear, Artemis recomposes Apollo using the high output of the moment in which the Concept Cores in Typhon and Kevranos are joined together. However, it could take quite some time even several thousand years for the recomposition to stabilize and until then Apollo will be in a comatose state. Meanwhile, Miyako is left behind pregnant with his child, hoping to see the day Apollo wakes up.
- Curtains Match the Window: Yellow hair and eyes.
- Hair of Gold, Heart of Gold: He is described as a pacifist and he acts like a kind and princely young man.
- Ill Boy: He clearly has poor health and always looks pale and sickly.
- Last of His Kind: The last living human man of 3rd-Gear.
- Long-Haired Pretty Boy: He has long blonde hair that contributes to his princely looks.
- Long-Lived: He is part of a race that could live for thousands of years.
- Man in White: He wears a white outfit.
- MayflyDecember Romance: With Miyako. He has likely lived for thousands of years while she's a regular human of college age.
- Princely Young Man: The Prince Charming type. He's the member of a royal family who lives in a Big Fancy House filled with Robot Maids.
- Really Gets Around: Apollo claims had to be with many women to try and increase his world's population because he was one of the few 3rd-Gear humans with the ability to reproduce. However, he later admits he never actually did the act with any of them because 3rd-Gear had everything was extracted and done outside the body.
- Really 700 Years Old: He looks like a young man, but he has lived for at least a couple of millenia.
- Reluctant Warrior: Despite being a pacifist, during the Concept War he was forced by his father to fight.
- Supernatural Gold Eyes: His yellow eyes are fitting of someone with the name of the Greek sun god and a member of a Long Lived Race.
- Synchronization: Since Apollo's re-composition was imperfect after Artemis overwrote his death, Apollo is synchronized with Typhon. Therefore, any damage Typhon receives is transferred to Apollo and vice versa.
- Wacky Marriage Proposal: He simply bows and asks Miyako to marry him before even properly introducing himself.
- What Beautiful Eyes!: Miyako finds herself drawn to Apollo's eyes because of their color and their look reminding her of herself.
The leader of the Army and former general of 9th-Gear. He acts as an information broker for other Gears while working on his own mysterious plans.
- Affably Evil: For the leader of a shady organization that is moving everything behind the scenes, Haiji is a very polite and accurate fellow.
- Big Bad: He's the leader of UCAT's main enemy the Army and the main antagonist of the series.
- Even Evil Has Loved Ones: As shady as he can be, he does seem to genuinely care about his adoptive daughters.
- Eyepatch of Power: He wears an eyepatch over his left eye.
- Hidden Agenda Villain: For a good part of the series, we have no idea what he and his Army are up to and what are their motivations.
- Knowledge Broker: He acts as an information broker who can gather weapons and accurate information.
- Power Limiter: His eyepatch acts as one for his Concept Weapon.
- Well-Intentioned Extremist: He claims everything he does is for the sake of eliminating the "real villains" and give Low-Gear back to "those it truly belongs to".
Haiji's elder "daughter".
- Action Girl: She's one of the main fighters of the Army.
- Aloof Big Sister: She's emotionally distant to everyone, including her adoptive sister Shino.
- Aloof Dark-Haired Girl: She's tall, attractive and has a reserved and composed personality.
- Badass Longcoat: She usually wears a dark longcoat, which contributes to her cool and serious image.
- Bifauxnen: She likes to wear men's-style suits.
- Distaff Counterpart: She's Sayama's female counterpart from Top-Gear.
- Evil Counterpart: To Sayama. It helps they are literal opposite-sex counterparts from different worlds and their own respective Gears' representatives.
- Forgotten Friend, New Foe: She claims to have known Shinjou before she lost her memory and they were close in some way, but now they are enemies as members of the Army and UCAT respectively. Mikoku really doesn't want Shinjou to be her enemy, though.
- Meaningful Name: Mikoku means "to carve into life".
- Rapunzel Hair: She has very long knee-length hair that she keeps in a ponytail.
- The Stoic: Never shows emotion.
- Tsurime Eyes: She has sharp eyes, to reflect her serious and stoic character. Same as Sayama. This could be a hint they are opposite-sex counterparts.
Haiji's younger "daughter" and Mikoku's "sister". She possesses a philosopher's stone which allows her to interact and control spirits of small animals like dogs.
- The Beastmaster: She can use her philosopher's stone to gather dogs' spirits and have them under her command.
- Hair Decorations: She wears a headband in her hair.
- Tareme Eyes: She has big, round eyes and she's young and innocent.
A member of the Army and Mikoku's teacher. Until five years ago, she lived at the Hiba Dojo under the name of Miki Hiba and was Ryuuji's older sister figure.
- Action Girl: She's a very capable swordswoman.
- Cain and Abel: The Cain to Ryuuji's Abel. She abandoned his family to join the Army and has made clear their former sibling bond means nothing to her, only thinking of him as an enemy.
- Distaff Counterpart: She's Ryuuji Hiba's female counterpart from Top-Gear.
The mechanical dragon force of the Army. He's a self-proclaimed "ally of justice". He has been affected by an incurable disease caused by a negative concept, which is why he has been combined with a mechanical dragon in order to slow down the process.
The head of the Tamiya family. An absentminded and irresponsible woman, she leaves most of the work to her younger brother. She was in love with Sayama's father and had a fling with Sayama long ago.
- Cloudcuckoolander: She has a weird thought process.
- The Ditz: She's very absentminded, clueless and careless.
- Foolish Sibling, Responsible Sibling: The foolish to Kouji's responsible. Ryouko is ditzy, irresponsible and childish, Kouji is serious, reasonable and mature.
- Hopeless with Tech: She admits she's no good with machines that have more than two steps. Her brother tells her she should learn how to use the video player, the stove, the stereo, and the washing machine.
- Love Father, Love Son: She was in love with Sayama's father. After he died, she slept with Sayama and still shows something of a lingering attraction to him, but it's implied it merely comes from his resemblance to his father.
- Meganekko: She wears glasses; in personality, she's pretty ditzy and even childish.
- Oblivious to Love: She has no idea that Atsuta has been in love with her since highschool.
- Pining After Protagonist's Parent: She loved Sayama's deceased father, but the feeling wasn't reciprocated.
- Plucky Comic Relief: Almost all the scenes she is in are purely comical.
- Reckless Gun Usage: She carries around a gun despite having no idea how to properly use it. She uses it like it was a toy and tends to lose it.
- Shipper on Deck: She supports Sayama's relationship with Shinjou. Funnily enough, she would prefer Sayama to be with "Setsu" instead of "Sadame".
- Student Council President: She was this back in highschool.
- Womanchild: She acts very childish and immature most of the time and her younger brother has to reprimand her.
Ryouko's more responsible and reasonable younger brother. He's the one who does most of the real work for the family.
- Cloudcuckoolander's Minder: Always the one in charge of keeping his sister's absurdity under control and punish her when she does something stupid.
- Foolish Sibling, Responsible Sibling: He's much more serious, responsible and mature than his older sister Ryouko and he's always the one to scold and punish her for her foolishness.
- Straight Man: He takes this role as the one to deal with his ditzy sister.