Characters appearing in Radiant. Beware of unmarked spoilers.
Voiced by: Yumiri Hanamori (Japanese), Christopher Llewyn Ramirez, Cristina Vee (child) (English)
The protagonist, a reckless teenager infected by a Nemesis back when he was a child, which gave him a pair of small horns. His goal is to find the Radiant, the source of all Nemesis, to destroy it and end the infected's suffering.
- Adaptational Dumbass: A very strange example − the first two episodes made it seemed like anime!Seth was less impulsive and reckless than his early manga counterpart (see Destructive Savior below), but then the following episodes make him much more ignorant than he initially was. In the manga, he's the one who first brings up the Radiant, he knows not to reveal his barehanded magic to the Inquisitors, can perfectly ride a Flying Broomstick and can use basic spells like Repulse or Meteor Drops from the start. In the anime he's puzzled when Alma tells him about the Radiant, doesn't seem to know what the Inquisition is, isn't very good at flying and can't use any magic other than his "Titan Punch" (just a Fantasia-charged normal punch).
- Calling Your Attacks: He does this all the time during fights. Although, there is an in-universe explanation for it because of how Fantasia works. As Yaga put it, naming your attacks is a way to mnemonically link the name with the intention.
- Destructive Savior: His big problem in the introduction arc. He's so eager to prove that he can fight Nemesis that he deliberately makes a Nemesis egg hatch in the middle of a town with civilians around, causing no small amount of damage afterwards, with the bonus of tying up two kids to take them to "safety" (actually to the building where everyone is held hostage). Don Bossman sarcastically points out later on that Seth actually did far more damage than the villains. This is greatly toned down in the anime, where the egg hatches on its own and Seth doesn't make any such stupid decisions. He doesn't really show this trait later on in the manga either.
- Green Thumb: A skill he acquires after his training with Myr in the Caillte forest to feel the Fantasia. It also symbolizes how much his worldview has matured thanks to it.
- Horned Humanoid: What's normally a harmless and fairly easy-to-hide infection soon becomes a plot point. Because of his horns, the Inquisition accuses Seth of a number of crimes he obviously didn't commit, yet has faint memories of. It turns out Seth has several horned "brothers" he's mentally connected to. They are all implied to have been born infected, something normally impossible.
- Overly Long Name: "Jean-Pedrovitch de la Noche Salomon Grispépin Wondersmith", the name randomly given to him by Master Lord Majesty after Seth joins the Artemis. The anime gives him the title of "King of Debt" instead.
- To Be a Master: Defied. Seth doesn't care about being "the greatest sorcerer" or the best at this or that. It reflects the author's distate for competition in his own field.
- Unskilled, but Strong: While he's fast and agile enough to dodge attacks and can use a magic shield, Seth's fighting style (especially early on) can usually be summed up by "punch stuff, and if that doesn't work, punch harder." As a result he ends up taking quite a bit of abuse, and his magic barrier doesn't always work due to his enemies often wielding weapons made of anti-Fantasia materials.
- Vocal Dissonance: Seth is supposedly a 15 or 16 yo teenager, which makes his female voice in Japanese quite jarring. Between that and his more childish and ignorant behavior, anime!Seth rather sounds and behaves like he's 12.
Voiced by: Aoi Yuuki (Japanese), Caitlin Glass (English)
A kind and polite young woman, specialized in magic traps, who lives in the Artemis Institute. Problem is, her infection causes brutal and unpredictable personality changes that turn her into an aggressive and spiteful girl. She's always accompanied by a small, flying, horned creature she calls Mr. Boobrie.
- Barrier Warrior: Since she's specialized in traps, most of her combat spells are defensive in nature unless she's in her angry mode, in which case she can wield some pretty scary offensive magic.
- Chickification: While still badass to an extent, Mélie acts a bit more childish and needs to be saved more often in the anime (especially in the filler episodes).
- Expository Pronoun: Uses the polite second person pronoun "vous" to address others, even Mr. Boobrie. After the Cyfandir arc, she unconsciously starts to use "tu" with Seth, which the latter gleefully points out.
- Fiery Redhead: When her infection kicks in she becomes much more violent and irritable. Strangely enough, Mr. Boobrie seems to be in love with that version of her. Even Ocoho prefers her that way, since angry!Mélie makes a perfect sparring partner.
- I Just Want to Have Friends: Because her infection makes everyone afraid of her. She's so desperate to have friends that she made human-shaped cardboard cutouts that she talks to when she's alone.
- Mood-Swinger: Initially Played for Laughs, but eventually Played for Drama. Her mood swings are totally out of her control and have several times put her loved ones in danger, which caused her to be isolated and friendless.
- Nice Girl: As her normal self she's as sweet as can be, to the point of being slightly naive at times.
- Split Personality: While shes a Nice Girl, when she comes under extreme stress (at least in the anime) her other personality takes over and she becomes a Fiery Redhead.
- Storyboard Body: According to the author, her tattoos are meant to represent episodes of her life. The spider web for example represents the Nemesis that killed her sister Vénélope.
- Trap Master: Her speciality. She uses all sorts of parchments and other objects to trace and capture Nemesis, which comes in handy against Hameline.
- Unishment: Angry!Mélie actively invokes this on the very masochistic Mr. Boobrie, promising to give him a good beating as a reward if he follows Brangoire in the Cyfandir arc. She doesn't need to ask twice.
Voiced by: Shintaro Ohata (Japanese), Shawn Gann (English)
A researcher from the Artemis who doesn't use magic but makes a living by cleaning up and selling the remains of dead Nemesis. He also works as Mélie's informant, but he's terrible at it according to her.
- Accidental Hero: Plays an important role in the battle of Cyfandir by activating the armor of Penn Draig, protecting the Queen and defeating the Thaumaturge Vérone, because he hid in the armor while carrying memory stones containing the spirits of old heroes. Doc being Doc, it was all entirely out of his control.
- Born-Again Immortality: Not quite since him being immortal is debatable; his old body died in Rumble Town but his infection has him actually shed it and then he became a baby.
- His Name Really Is "Barkeep": One might think that "Doc" is just a nickname, but it's actually the name written on his license.
- Hopeless Suitor: One of the weirdest examples out there. He's in love with Miss Melba, a cute café waitress who's always talking to her "father" (actually a hand puppet) who "tells" her he disapproves of Doc. Doc himself doesn't seem to question it.
- Lovable Coward: He's not a bad guy at heart, but prefers to stay as far away from danger as possible. Seth being the disaster magnet he is, Doc is understandably reluctant to help him at first.
Voiced by: Romi Park (Japanese), Monica Rial (English)
Seth's mentor and adoptive mother, who has no memories of her life before meeting with him. Her infection gives her frequent headaches, which partly explains her perpetually annoyed expression.
- The Dreaded: Alma is feared by anyone who has ever crossed her path. Even Yaga, a very powerful sorcerer, almost pisses his pants just because Seth imitates her for a second.
- Handicapped Badass: despite losing a limb, she is still powerful.
- Life-or-Limb Decision: According to Seth, she had to cut off her own arm to prevent a Nemesis' curse from killing her.
- Parental Substitute: Alma's the closest thing Seth has to a mother, and despite her harshness and occasional abuse (Played for Laughs) she does cherish him. Later on, it becomes unclear whether Seth even has biological parents to begin with.
Don Bossman voiced by: Tetsu Inada (Japanese), Marcus D. Stimac (English)
Crook sorcerers who pretend to come to fight the Nemesis but actually take advantage of the chaos to steal money and treasures in various towns. After being captured by Alma, two of them escape, but Don Bossman and Jiji become her devoted assistants.
- Starter Villain: They resent uninfected people for their discrimination and, unlike Seth, have absolutely no intention of helping them or fighting the Nemesis. They mostly serve to contrast Seth's willingness to protect people despite his own rashness − and despite the fact that he does resent them for all the shit he and Alma have gone through.
Voiced by: Takehito Koyasu (Japanese), Eric Vale (English)
A bandaged man who often crosses paths with the protagonists and occasionally helps them, while seemingly pursuing his own mysterious goals.
- Afraid of Blood: More specifically, he seems terrified of losing his own blood, to the point he collects every drop he loses in small flasks.
- Bandage Mummy: Why his body is entirely covered in bandages is unknown, which adds to his mystery.
- Third-Person Person: Grimm always refers to himself this way, which gives him a haughty vibe, along with his very formal way of speaking.
- Wild Card: Nobody knows what he wants, and he only seems to help the heroes in his own interest. His stance becomes even more ambiguous when he takes Hameline's Nemesis with him at the start of volume 11, with the intention of putting them to use.
Voiced by: Hiroyuki Yoshino (Japanese), Doug Jackson (English)
A famous sorcerer, member of the Coven of the Thirteen and an acquaintance of Alma. The latter wants him to teach the magic arts to Seth.
- Magic Cauldron: He is often in one and uses it to cast spells.
Voiced by: Kappei Yamaguchi (Japanese), SungWon Cho (English)
A yellow cat who is also the leader of the Artemis Institute. He's also quite the trickster and will make the sorcerers pay money for the most absurd things.
- Bunny-Ears Lawyer: He's seemingly fickle, deceptive and greedy, which is all Played for Laughs, but he's clearly not someone the Inquisition nor the sorcerers take lightly. While his magic power is unknown, his political influence is very real and has allowed the Artemis to remain a safe haven for sorcerers.
- Department of Redundancy Department: Apparently the fact that he's the boss had to be emphasized three times in his name.
Voiced by: Ryohei Kimura
Claims to be Seth's older brother, despite Seth himself having never heard of him. He's a sorcerer, yet seems to work with the Inquisitor General Torque.
- Affably Evil: At least what is implied from Diabal's testimony. He's always polite and composed, even genial, but his actions don't paint him as someone who particularly cares for his "brother"'s well-being.
- Long Lost Sibling: What he claims to be to Seth and several other horned boys. It's not clear, however, what he means by "brother", since Seth had never heard of him before their meeting.
- Manipulative Bastard: Increasingly implied to be this as the story progresses. First, in the Rumble Town arc, he awakens an extremely dangerous power within Seth, that saves the latter's life but also threatens to swallow him whole. Later we learn that Seth is far from the first horned boy who met with Piodon, and none of them had a happy ending. Combined with the fact that he works with the Inquisition for unknown reasons, he's clearly not the most trustworthy guy out there.
A man who hides deep inside the walls of Caislean Merlin and seems terrified of Piodon. He uses a magic device to summon "Spectrums", giant projections of anything inside the device, that the Magic Knights take for actual Nemesis.
- Scars Are Forever: He kept heavy scars from being tortured by the Inquisition courtesy of Piodon who handed him and another brother to the inquisitors after raising and protecting them.
Voiced by: Yumi Uchiyama (Japanese), Trina Nishimura (English)
A Domitor Witch who can control a horde of Nemesis with her magic and has sworn to destroy Rumble Town.
- Anti-Villain: On one side, she sets a horde of Nemesis loose on Rumble Town and threatens to destroy the entire city. On the other, she deeply cares for the Nemesis that saved her life, wants to end the oppression on the infected and as Seth points out, doesn't actually kill anyone in her "rampage". Her arc ends with her entrusting her Nemesis' care to Seth before sacrificing herself to let him escape from the Thaumaturges.
- The Beastmaster: She has trained to command the Nemesis that run around Rumble Town.
- Magic Music: She uses a flute to direct her army of Nemesis. This comes from the day of her escape, when she realized the sound of the flute that Captain Oxumare had given her calmed the Nemesis down.
- Meaningful Name: A reference to The Pied Piper of Hamelin, as she controls Nemesis that look like rats with her flute.
- Not So Different: Everything she says about her life are things that Seth has experienced himself. She even points out that Seth uses words like "us" and "them" when talking about infected and non-infected, which she thinks proves they are exactly in the same boat, no matter how much Seth denies it. And he eventually agrees, fooling Hameline into thinking he wants to join her but he refuses to give in to revenge. Narratively, she leads Seth to nuance his own views for the first time, while he encourages her to nuance hers.
- Pointy Ears: A result of her infection, along with grey stripes on her body. Graphically, the ears and the pointy hood give her a very "fairy tail-esque" appearance, tying to the reference in her name.
- Tyke Bomb: At least initially. She was taken from her parents and raised by the Inquisition to make her a weapon against the Nemesis, but ended up taking the Nemesis' side against the humans who treated her like a monster.
A Domitor who disguises as an ordinary assistant on a zeppelin headed for Bome (where the Inquisition's headquarters are). She uses a book to capture her targets.
- Clark Kenting: She sports a pair of round glasses when disguised, to pass as ordinary and harmless.
Voiced by: Koji Yusa (Japanese), Ivan Jasso (English)
Inquisitor Captain in charge of the Pompo Hills region, he's loyal but can be a bit of a wild card. He fights with a bow and has nigh-superhuman eyesight despite missing one eye. His missions will lead him to crossing paths with Seth and co. several times.
- The Archer: The only character in the series who fights with a bow, albeit with an unorthodox shooting style (his right hand is reversed when stretching his bow). He has the Improbable Aiming Skills to go with it especially after becoming a Thaumaturge.
- Deadpan Snarker: Mostly shows this toward Konrad, who used to be his subordinate. A subdued way to show his hostility to the guy, especially when it becomes clear that Konrad is behind some dirty schemes.
- Eyepatch of Power: How he lost his left eye is unknown, but the remaining one works extremely well. Visually, it adds to his general charisma.
- Reasonable Authority Figure: Usually knows when it becomes unreasonable to blindly chase the sorcerers while there are other priorities, and his attitute toward them is generally less hostile than the other inquisitors'. In the Cyfandir arc, he even briefly sides with Mélie and Grimm to help them stop a rampaging Seth.
- Supreme Chef: If the anime's anything to go by, his cooking is one big reason his subordinates are so eager to work under him.
- Took a Level in Badass: After the Rumble Town arc he's made a Thaumaturge and acquires the power to teleport wherever he shoots his arrows.
Voiced by: Kenichi Ogata (Japanese), Kent Williams (English)
Inquisitor Colonel, and the oldest of the Thaumaturges, who can materialize a huge spectral version of himself. He's fond of recounting his many exploits.
- Astral Projection: His power, to manifest a huge version of himself or his limbs.
- Blood Knight: His appearance and pose give him an "old sage" vibe, but in combat he's anything but. His spends his fight against Seth in the Cyfandir arc either lamenting his weakness or saying he's having the time of his life.
Voiced by: Ayane Sakura (Japanese), Jamie Marchi (English)
Inquisitor Captain, who used to work under Dragunov before she became a Thaumaturge. She's a harsh woman but still has a deep respect for her former superior.
- Blush Stickers: Hints at a (very well hidden) delicate side that contrasts with her stern attitude.
- Dual Wielding: She fights using a pair of short swords that she can control from a distance thanks to her Miracle.
- Unresolved Sexual Tension: While Dragunov doesn't show much emotion, Liselotte is implied several times (especially in the Cyfandir arc) to have more than strictly professional feelings towards him, which Von Teppes mocks her about. She remains dedicated to her missions nonetheless.
Voiced by: Saori Hayami (Japanese), Bryn Apprill (English)
Inquisitor Commander, also a Thaumaturge. She's a very pious and seemingly naive woman who hides a more perverse nature.
- Ambiguously Brown: She has white skin in the black-and-white pages, but is actually a light brown in color illustrations and in the anime. Also the only Dark-Skinned Blonde in the series.
- Covert Pervert: Makes frequent comments about the "dirty" habits of sorcerers, usually alluding to sexual practices in some way, all while blushing, and with the occasional Double Entendre.
- Cute and Psycho: Acts very sweet and kind most of the time but reveals herself to be very deranged during the climax of the Cyfandir battle. When Seth loses his mind in a Roaring Rampage of Revenge after Jill's death, she catches him for a brief moment during which she feels every bit of his pain and sadness. And she loves every second of it to the point of addiction.
- Palm-on-Cheek Pose: A frequent gesture of hers (with one or both hands), reinforcing her falsely sweet and dreamy attitude.
- People Puppets: Her Miracle allows her to control corpses, no matter how many there are. Now imagine being on a battlefield, killing hundreds of enemies and seeing hundreds of your countrymen die then seeing those enemies and those countrymen suddenly back on their feet to kill you. She can use it on living peole, but it's implied to be much more dangerous for her.
- Supernatural Gold Eyes: Ullmina sports these, which matches both her frightnening powers and the fact she's by far the most religiously fanatic of the Thaumaturges. They're further contrasted by her dark skin.
Voiced by: Takuma Terashima (Japanese), Ian Sinclair (English)
Inquisitor Commander. He's powerful but also quite impulsive.
- Nice Job Fixing It, Villain!: At the end of the Rumble Town arc, he almost kills Seth by breaking his neck, as the latter was trying to attack Torque. This triggers Seth's Superpowered Evil Side and indirectly allows him and his friends to get away from the Thaumaturges. When Teppes tries to attack Seth again, he gets promptly knocked down with a single hit.
- Put on a Bus: He hasn't been seen since losing against a super-powered Seth in Rumble Town. A line from Torque in volume 5 implies that he might have been stripped of his Thaumaturge title, which the anime confirms in episode 20.
- Weapon of Choice: Uses a big mace to fight, adding to his brutish image.
Prince of the Convictis kingdom, he's a Thaumaturge despite still being a child, and is rather intelligent.
- Enfant Terrible: Holds a frightening power and can kill without hesitation despite his young age. When it's revealed that he's Ullmina's son, that explains a few things.
- Taken for Granite: When he rings his bell, everything within the radius of his Miracle is petrified − including concentrated Fantasia.
Voiced by: Kenta Miyake (Japanese), Ray Chase (English)
Inquisitor General who helms the Thaumaturges. He seeks to perpetuate the will of the "Patrem Inquisitor" and rid the world of sorcerers.
- Badass Baritone: as if being voiced by both Kenta Miyake and Ray Chase wasn't enough.
- Four-Star Badass: a General who leads the Thaumatruges.
- Well-Intentioned Extremist: Claims that he wants to get rid of sorcerers to avoid the return of the old age where magic ruled the world and the oppressed were those without it.
Voiced by: Katsuki Murase (Japanese), Patrick Seitz (English)
Formerly a subordinate of Dragunov, he's now Captain of the Inquisitors in Rumble Town. He mostly hates two things: infected people and foreign refugees who "soil" the island.
- Badass Mustache: The one thing everyone praises about him is his beautiful − and extremely long − mustache.
- Bald of Evil: Another early sign that he's not gonna be a nice guy.
- False Flag Operation: Konrad's plan was for Hameline to deploy her Nemesis under cover of the constant evacuation drills, then eventually when her forces are built up enough, break out and attack the city, strategically targeting areas to make sure the undesirable elements are evacuated/corralled into one district, then drop the main tower's giant bell on them. Afterward, Konrad would use the fresh fear of sorcerers to whip the people into a frenzy and unleash them on the remaining immigrants.
- Jousting Lance: Wields a giant one as his Weapon of Choice, made of white silver to repell Fantasia. The tip can double as a Grappling-Hook Pistol.
- Named After Someone Famous: Konrad de Marbourg was the first German inquisitor in the 13th century.
- Politically Incorrect Villain: His prime goal is to rid Rumble Town of immigrants − he already killed many (indirectly but willingly) during the Norst-East Suburb incident − and he's notorious even among his co-inquisitors for being a racist jerk. The author clarifies that some of his dirtiest lines are almost verbatim quotes from real politicians, including former French Prime Minister Manuel Valls.
An Inquisitor General like Torque, who came from the Great South, a region struck by many disasters in recent times.
- Bunny-Ears Lawyer: A little quirky on the edges, but otherwise eloquent and obviously a competent fighter.
- Literal-Minded: Ininna warns anyone who talks to him to chose their words carefully, as he has trouble with figurative speech. E.g., when the captain of the ship asks if the decorations are to his taste, he proceeds to literally taste them with his tongue.
- Meaningful Name: He's named after an Akkadian king who ruled over Mesopotamia around 2300 BC.
- Royal Rapier: Gives him an air of nobility, along with a High-Class Glass.
Inquisitor Colonel who accompanies Sargon to Bome.
- Cloudcuckoolander's Minder: Rather, she informs other people of her General's peculiar traits.
- Meaningful Name: Probably named after Inanna (also known as Ishtar), the Mesopotamian goddess of love, fertility, war and power.
- Scars Are Forever: Her scars and rather muscular build indicate that she's an experienced fighter.
An aspiring Magic Knight who brings trouble to herself more often than she'd like due to her rather hot-blooded temper. She rides a giant flying raccoon called Draccoon.
- Ambiguously Brown: has dark, almost black skin but otherwise undefined facial traits. To make things more confusing, half of her hair sports distinctly African-looking braids, but the other half is smooth and spiky.
- Braids of Action: Sports one long braid on her side, fitting her impulsive character and love of action.
- Character Tic: Has a habit of joining her hands in a triangle in front of her mouth when she smiles embarrassingly.
- Extremity Extremist: A rather peculiar instance, where she doesn't fight with her legs but her knees specifically. She has a special armor customed to that end.
- Psychic-Assisted Suicide: What Mordred tries to do by using her infection and ordering her to jump off the deck of a flying ship. Her Gysoni link with Draccoon snaps her out of it however, and she decides to use that very spell to manipulate him instead.
- Psychic Powers: She can use Gysoni, a spell that links her senses with those of a group so that they can act as one. Except hers is so powerful she can take it to the level of People Puppets. It's also noted that she has a real talent to see what's Invisible to Normals, like the ghosts of extinct species in the Caillte forest. She also learns effortlessly to communicate mentally through the Sidh.
- Sixth Ranger: Helps the protagonists during the Cyfandir arc and joins them for good when she's crowned princess of Cyfandir and leaves the kingdom to see the world.
Queen of Cyfandir, a kingdom where the infected can live without fear of the Inquisition. She's a gigantic woman who has the strength to go with it as well as the ego.
- Knuckle Tattoos: Has the letters of "QUEEN" tatooed on each of her knuckles. Just another detail to emphasize her massive ego.
- Large and in Charge: Her infection turned her into a giant woman, taking Statuesque Stunner to a whole new level. She's also every bit as powerful and charismatic as her size suggests, and messing with her kingdom − home to thousands of sorcerers − is a very bad idea. It's safe to say her sole presence is part of the reason the Inquisition has left Cyfandir alone.
The leader of the Magic Knights, who's as devoted to his Queen as he's demanding to his subordinates.
- Badass Beard: The author initially thought of giving him an afro haircut, but chose to put the afro on his chin instead.
- Drop the Hammer: Wields a big hammer that fits his imposing physique and Large Ham personality.
- Traitor Shot: Has a few hooded ones when he's shown spying on Ocoho in volume 7. It makes the heroes suspect him of being part of the conspiracy with the "Spectrums", but it turns out it was Ocoho who (unknowingly) took part in it. So he had very good reasons to spy on her.
Childhood friend of Ocoho and an aspiring Magic Knight like her. Considered one of the most promising of his generation.
- Childhood Friend: He has known Ocoho ever since they were in school, along with their other friend Sagramor. Ocoho was implied to have a crush on him too before she realized what he was.
- Et Tu, Brute?: Volume 9 reveals that he was a spy sent by his father (a baron-merchant) and manipulated Ocoho to further the barons' plan to claim Cyfandir's land.
- Lack of Empathy: His infection made him completely emotionless, so he has absolutely no qualms betraying and killing even his closest friends. After he kills Sagramor and Ocoho uses her Gysoni to control him, he feels every bit of her rage and sadness and begs her to stop. She makes the Gysoni stronger to punish him.
- Walking Spoiler: He only has a few scenes before his betrayal, meaning that most of his characterization occurs after it.
An excentric man who hangs around Caislean Merlin, Cyfandir's capital, and has become rather infamous for his bad hygiene and bawdy songs. He wears a human-shaped beard with underpants. Because.
- Affectionate Nickname: His full name is Myrddin, which was the real name of Merlin. Obviously, we don't learn that until much later in the arc.
- Almighty Janitor: Behind his goofy exterior, he's able to communicate with plants and knows quite a bit of magic. Considering he's the ancient mage known as Merlin, it comes with the territory.
- Little People: The last survivor of the "Small Folk", who were partly driven to extinction by the expansion of mankind and the subsequent rarefaction of Fantasia, which they fed on.
- Really 700 Years Old: He looks like a portly midlle-aged guy, but is actually 853 years old and that's just counting his time spent in the human world.
- Walking Spoiler: The reveal that he's Merlin changes everything we knew about him, which makes it next to impossible to mention him without spoiling.
Myr's wife, she's a sentient tree who holds tremendous magic power and made their forest isolated from time and from humans.