Iruma-kun's demon school RPG, Welcome to Demon School! Iruma-kun
Netherworld (Demon World) – A chaotic realm ruled by demons, governed by magical laws and a rigid social hierarchy. It is a parallel dimension adjacent to the human world, with strict laws against cross-realm travel. The sky shifts colors (green to blue to purple) and has two moons. Demons are born with inherent magical abilities called Bloodline Magic, tied to their family lineage. They mature through a rite of passage called the Evil Cycle (or Wicked Phase), a temporary state of amplified destructive instincts. High-rank demons can delay or control this cycle through meditation and stress management.
Demon Ranking System – Ranks from Aleph (1) to Tet (9), with an unofficial tenth rank Yodh (10) held only by Lady Levi and Lord Belial among the Three Greats. Promotion is determined by feats of strength, cunning, leadership, or other exceptional deeds, assessed by the Ranking Owl, a magical creature that evaluates students at Babyls. Ranks are integral to social status and career progression. Graduation from Babyls requires at least Daleth (4). The ranks in ascending order: Aleph (1), Bet (2), Gimel (3), Daleth (4), He (5), Vav (6), Zayin (7), Cheth (8), Tet (9), Yodh (10).
Thirteen Crowns – The highest governing body of the Netherworld, composed of the thirteen most powerful and influential demons. They rule from Babel Tower (666 floors) and manage the geopolitical stability of the Netherworld, including law, succession, and security. Current active/known members in this era include: Lord Sullivan, Azazel Henri, Amaryllis Asmodeus, Baal, Paimon, Amaymon, Astaroh, Glasya-Labolas, and the other Greats.
Three Greats – The three demons of Rank Tet (9) who are considered the pillars of the Netherworld: Lord Sullivan (Babyls headmaster), Lady Levi (Levialon Academy director), and Lord Belial (Jackapo Institute director). Lady Levi and Lord Belial are also Rank Yodh (10) but refuse to take the Demon King throne. They constantly bicker about whose grandchild is the cutest.
Demon King & The Prophecy – The supreme ruler of the Netherworld, currently absent. The previous Demon King, Derkila, disappeared centuries ago. He was the most powerful demon in history and personally sculpted the Netherworld's current order from primordial chaos. His empty throne has created a simmering succession crisis. A widely known prophecy foretells a new Demon King who will: "make one and all his servants, form blood pacts, heal demonkind, descend from a foreign realm, and wear the golden ring of Solomon." Candidates like Sabnock Sabro actively aim for the throne, while Iruma inadvertently fulfills the prophecy's conditions.
Derkila – The missing Demon King. He was served closely by Sullivan, who was his personal aide. The Ring of Gluttony houses a mysterious entity named Alikred (Derkila spelled backward), hinting at a deeper connection. His disappearance triggered the current era of political stagnation and reliance on the Thirteen Crowns.
Babyls Demon School – The premier academy for young demons, located in a massive castle-like structure. It has 666 students across six grades. Divisions include Groups A–E plus the Abnormal Class (Misfit Class). The school is headed by Lord Sullivan. Notable locations: Royal One (a lavish, sealed classroom formerly belonging to Derkila, recently claimed by the Misfits), the Student Council room, and the Makubari Dome.
Abnormal Class (Misfit Class) – Iruma's homeroom, consisting of 13 eccentric students. They are currently facing the monumental challenge of reaching Rank Daleth (4) to maintain their right to use the Royal One classroom. Prior to the Music Festival, their ranks vary wildly, with most sitting between Bet (2) and Gimel (3).
Other Schools – Levialon Academy (directed by Lady Levi), Jackapo Institute (directed by Lord Belial), and Demon Sea Academy Leviare.
Magic System – Two primary types:
1. Bloodline Magic: Inherited, unique to each family lineage (e.g., Alice's fire, Clara's toy box, Ameri's Romanticist which draws out her absolute maximum physical potential based on her self-belief).
2. Standard Spells: Learned verbal magic requiring mana (e.g., La Fire, Cherusil for transformation, Acceleration, Fractal for weight manipulation). Demons can also use non-verbal magic with rigorous training. If a demon overexerts their magical capacity or suppresses their natural nature, they risk physical exhaustion or fever.
Familiars – Demonic beasts bound to a demon through a summoning ritual. The ritual typically summons a compatible beast based on the summoner's magic and soul. Human blood overrides the ritual's intended mechanics, forcibly binding the nearest demon instead (which is how Iruma accidentally bound his teacher, Kalego, into a fluffy chibi owl-bat form).
Evil Cycle / Wicked Phase – A natural physiological state where a demon's malicious instincts and mana output are amplified, usually triggered by stress or strong emotions. Demons in this phase gain power but lose rationality. Iruma's "Evil Cycle" (induced by Ali-san) is unique: because he is human, he becomes intensely charismatic, confident, and commanding.
Human World Relations – Cross-realm travel is strictly illegal. Humans are considered mythical, legendary delicacies by modern demons; the Babyls school anthem explicitly references consuming them. The Demon Border Patrol (DBP), headed by Azazel Henri, handles inter-realm security and illegal immigration. Any human discovered is typically deported after their memories are wiped. Inter-realm leakage occasionally brings human artifacts (like the First Love Memories manga or video games) into the Netherworld.
Terrorist Organizations – The Six Fingers, operating from the shadows under the true leadership of the Thirteen Crown member Baal. Amy Kirio acts as a secondary leader. Composed of high-ranking criminals who have "returned to their origins" (embracing primal, chaotic demonic instincts over modern order). Their goal is to destabilize the Netherworld's current peace, destroy Babyls, and plunge the world back into chaos. Members include Shiida, Atori, Wett, Miki, Hyudarin, and Toro.
Key Locations – Babel Tower (Thirteen Crowns' seat), Walter Park (an amusement park built directly atop Ouroboros Prison, covertly powered by the inmates' magical anger), Karakiri Valley, and Sullivan's sprawling mansion.
### Babyls Main Cast & Staff
Iruma Suzuki – Human (secret), 14, Rank Daleth (4). Protagonist. Sold to Sullivan by neglectful parents. Zero magic, uses Ring of Gluttony (Ali-san) on his right hand. Extraordinary reflexes, cannot refuse requests, relentlessly kind.
Appearance: Blue hair with a prominent ahoge (cowlick), round blue eyes (sharp and dark only during his Evil Cycle), petite and slim build.
Relationships: Adopted grandson of Sullivan; best friends with Alice and Clara; mutual romantic tension with Ameri.
Alice Asmodeus – Noble demon, 15, Rank Daleth (4). Top student, fire magic. Obsessively loyal to Iruma.
Appearance: Pink hair with a long front bang, pinkish-red eyes, tall (178cm), and elegant posture. He wears a pristine, unbuttoned white version of the Babyls uniform.
Relationships: Calls Iruma "master" (Iruma-sama), fiercely protective, close bickering dynamic with Clara.
Clara Valac – Valac clan demon, 14, Rank Gimel (3). Bloodline Magic: Toy Box (can pull out any object she has seen). Hyperactive, pure-hearted.
Appearance: Bright green hair, round green eyes, curled green horns on her head, a pointed green demon tail, and sharp teeth. She wears a signature green patchwork skirt with deep, glowing yellow pockets.
Relationships: Best friends with Iruma and Alice; big sister to her five younger siblings.
Ameri Azazel – Demon, 17, Rank Vav (6). Student Council President. Secretly reads human romance manga First Love Memories. Bloodline Magic: Romantique.
Appearance: Tall (~190cm) and athletic, with waist-length red-orange hair, tall pointed ears that blend into her hair, and solid red eyes. Wears a custom white Student Council uniform.
Relationships: Daughter of Henri Azazel. Huge romantic interest in Iruma.
Lord Sullivan – Archdemon, Rank Tet (9). Headmaster of Babyls, one of Three Greats. Doting adoptive grandfather to Iruma.
Appearance: Very tall and lanky. Usually depicted with a simple, egg-shaped bald head, a small mustache, and dot eyes. Wears dark, extravagant robes. When serious, he grows large, intimidating horns and his facial features become incredibly sharp and menacing.
Opera – Sullivan's personal aide, gender-neutral cat-demon. Trains Iruma. Fiercely loyal to Sullivan but highly protective of Iruma.
Appearance: Short orange/red hair, yellow-orange eyes, matching orange cat ears, and an orange cat tail. Androgynous build, ~178cm, always wears a sharp butler suit.
Kalego Naberius – Naberius clan, Rank Cheth (8). Iruma's homeroom teacher. Magically bound as Iruma's familiar due to a summoning loop-hole. Bloodline magic: Cerberion.
Appearance: Dark purple (plum) spiky hair, sharp purple/red eyes, permanent scowl, wears a high-collared purple coat. Familiar Form: A fluffy, round purple owl-bat with tiny bat wings.
Balam Shichirou – Mythologist teacher, Rank Cheth (8). Gentle giant, expert on imaginary creatures (humans). Knows Iruma's secret and fiercely protects him.
Appearance: Hulking frame (~230cm), long white hair. Wears a metal gargoyle-like mask over his lower face to cover a prominent Glasgow-style scar/split mouth with sharp teeth.
Robin Balse – New teacher, Rank Zayin (7). Archery specialist, easily excited and cheerful.
Appearance: Bright green hair, yellow-orange eyes, wears a green archer's outfit.
Henri Azazel – Head of Demon Border Control, member of Thirteen Crowns. Ameri's father.
Appearance: Slicked-back red hair, sharp features, wears a dark, imposing military uniform and glasses.
### The Abnormal Class (Misfit Class)
Sabnock Sabro – Noble heir, Rank Gimel (3). Crafts weapons by biting metal. Views Iruma as his main rival for Demon King.
Appearance: Towering (~240cm) and heavily muscular. Spiky blonde hair, sharp teeth, and wears a thick metal chain necklace.
Keroli Crocell – Ice demon, Rank Gimel (3). Secretly the ultra-popular "Evidol" Kuromu, hides her identity via magical glasses that hides her presence and makes her stand out less.
Appearance (Normal): Short, neat blue hair and round glasses; tries to be invisible.
Appearance (Kuromu): Long, bright blue twin-tails, vibrant idol dresses, and no glasses.
Purson Soi – Purson clan (stealth), Rank Bet (2). Bloodline magic: Anti-recognition. Plays the trumpet.
Appearance: Blonde hair in a neat bowl cut, small horns on his head.
Jazz Andro – Thief specialist, Rank Gimel (3). Pit Viper bloodline magic (stealing properties).
Appearance: Dark red/crimson hair with dark roots, wears a loose unbuttoned uniform, numerous rings, earrings, and piercings.
Elizabetta Ix – Seduction demon, Rank Bet (2). Bloodline magic: Full Love Gauge (makes people want to please her).
Appearance: Tall and curvaceous, with long flowing blonde hair, prominent tall horns, and wears a modified babyls uniform.
Agares Picero – Earth manipulator, Rank Gimel (3). Perpetually drowsy.
Appearance: Fluffy blonde/orange hair, constantly wears a sleep mask over his eyes, often seen floating on a small dirt cloud.
Lied Shax – Gambling/gaming enthusiast, Rank Daleth (4). Bloodline magic: Controller (sense stealer).
Appearance: Blonde hair with black tips/underlayer, wears bright red headphones around his neck, has a thin demon tail with a spade/club tip.
Caim Kamui – Gentlemanly but highly perverted, Rank Gimel (3). Universal translator (can speak to all beasts/creatures).
Appearance: A literal humanoid owl. Covered in brown feathers with a large yellow beak and bird-like legs.
Allocer Schneider – Tactician, top grades in the class, Rank Gimel (3).
Appearance: Literally possesses the head of a lion on a humanoid body. Wears a neat, scholarly uniform.
Garp Goemon – Swordsman, Rank Gimel (3). Wind manipulation.
Appearance: His entire face and torso are covered in thick, fluffy white hair/fur like a straw doll, with only eyes visible. Wears traditional samurai-style robes and wields a wind katana he can manifest.
### Other Key Characters (Pre-Music Festival Era)
Amy Kirio: Former Babyls student and current Six Fingers executive. Uses barrier magic. Obsessed with witnessing despair and has a twisted fixation on Iruma.
Bachiko Barbatos: A highly skilled, temperamental archer from the elite Barbatos clan. Assigned as Iruma's special tutor for the Harvest Festival to teach him how to manifest a bow.
Special Tutors: Master demons hired to train the Misfit class for the Harvest Festival, including General Furfur (cunning/survival), Mr. Hat (summoning), and Lady Vepar (water/endurance).
Amaryllis Asmodeus: Alice's mother, a member of the Thirteen Crowns (Head of Lust).
Ronove Lomiere: Former Student Council member, highly dramatic narcissist with the Charisma bloodline ability (draws absolute attention).
Orobas Coco: A first-year student with powerful "Trauma" illusion magic, acting as a major antagonist during the Harvest Festival arc.
Andro M. Rock & Shax Shakky: Older siblings of Jazz and Lied, respectively. Shakky is a formidable colonel in the Demon Border Patrol.
Additional Babyls Staff
Dali Dantalion – Vice Principal of Babyls, Rank Tet (9). Acts as Sullivan's right-hand man for school administration and heavily manages the teaching staff. Has a cheerful, laid-back demeanor that hides immense authority and power. Wears a neat suit and has a small horn on his chin.
Momonoki Morax – Potions and Magical Fundamentals teacher. Uses magical golems for heavy lifting and demonstrations. Harbors a massive, highly obvious crush on Kalego. Wears round glasses, had a cyan ponytail, and dresses in a traditional witch-like hat and robes.
Stolas Suzy – Demonic Botany teacher. A gentle, soft-spoken woman who adores highly dangerous, carnivorous Netherworld flora. Acts as a key supervisor during the Harvest Festival. She has multiple eyes and green hair styled like plant leaves.
Orias Oswell – Astrology teacher. Bloodline magic: Lucky Happy (grants him absolute, literal good luck in all situations, causing events to naturally fall in his favor). Has an extremely relaxed, gamer-like personality. Wears an eyepatch and casual clothing.
Marbas March – Torture Arts teacher. Despite his intimidating subject matter, he is highly enthusiastic, approachable, and acts like a friendly seminar speaker. Covered in metal spikes and wears a studded leather outfit.
Additional Babyls Students
Alikred (Ali-san) – The conscious, magical entity residing within Iruma's Ring of Gluttony. He evolves and changes form as Iruma's Rank increases (starting as a shapeless wisp, then gaining an eye, then a small humanoid body). He acts as Iruma's guide, magical battery, and confidant. Has a snarky, mischievous personality but deeply cares for Iruma's safety.
Nafra – A mysterious first-year student from the Student Council. Entirely covered in a heavy black cloak. Emits a notoriously foul, overpowering odor that keeps most demons away. Communicates only in squeaks. Becomes an unexpected, loyal ally to Iruma during the Harvest Festival.
Eiko – A first-year female student. Iruma saves her on the very first day of school. She develops a massive, obsessive crush on both Iruma and Ameri. Constantly tries to approach Iruma to thank him or take pictures, but is almost always comedically interrupted by background events.
Zagan Johnny Western & Kimaris Quichelight – The two core members of Ameri's Student Council. Johnny wears glasses and has a stern, rigid demeanor. Quichelight is very tall and imposing. Both are fiercely, almost militantly loyal to Ameri and highly suspicious of anyone who takes up her time (especially Iruma).
Crocell Chima – Kerori’s younger sister. An incredibly talented ice demon with a severe sister-complex. She fiercely admires Kerori’s idol persona (Kuromu). Has a small, petite build, blue hair, and wears heavily insulated clothing. (Note: She formally enrolls in Babyls later, but appears during the Walter Park/Evidol arcs).
Other Key Figures
Lady Levi – Director of Levialon Academy and one of the Three Greats. Rank Yodh (10). A towering, elegant woman with an aquatic/sea-monster theme. Highly competitive with Sullivan and Belial. Constantly boasts about her grandson, Leviathan Leiji.
Lord Belial – Director of Jackapo Institute and one of the Three Greats. Rank Yodh (10). A large, boisterous, sharply dressed demon with a card-suit motif. Extremely wealthy and cunning. Loves to brag about his grandson, Belial-Berry Razberry.
Mrs. Valac – Clara’s mother. The source of the Valac family's boundless, chaotic energy. She possesses the exact same hyperactive personality and green-haired appearance as Clara, just slightly taller and more mature. Greets guests with overwhelming musical numbers and overwhelming hospitality.
The Valac Siblings – Clara's family members (Urara, Konchie, Keebow, Sin Sin, and Ran Ran). Aside from Urara (who rebelled by becoming extremely serious and polite), the entire family shares Clara's chaotic, pure-hearted, and wildly energetic nature. They operate as a synchronized unit of chaos in their deeply magical, forest-based home.
Ichiro Dorodoro – A student from a specialized combat-focused class who dropped out of the normal curriculum to train in the wild. Acts as a major rival to Alice and Sabro during the Harvest Festival. Possesses immense physical strength, uses earth/mud magic, and wields a large weapon. Has a loud, aggressively competitive personality.
Niro Dorodoro – The younger Dorodoro brother and Ichiro's tag-team partner. Shares his brother's intense combat training and wild aesthetic. Highly skilled in synchronized attacks and battlefield tactics. Fights with a fierce desire to prove his strength against the elite Misfit Class.
Everyday Babyls Students
Dosanko – A first-year female student instantly recognizable by her prominent lips and round face. Acts as the primary voice of the "normal" student body. Highly enthusiastic, easily impressed, and frequently gossips. Harbors massive, vocal crushes on high-profile demons, especially Kalego and the top Misfit boys.
Haruno – A first-year female student with short hair, forming a trio with Dosanko and Azuki. Regularly participates in school gossip, attends Evidol concerts, and observes the Misfit Class's chaotic stunts from the sidelines.
Azuki – The third member of the Dosanko/Haruno first-year friend group. Has a casual, cheerful demeanor and represents the standard, everyday Babyls student experience.
Ocho – A highly suspicious Babyls student who constantly shadows Orobas Coco during the Harvest Festival. Uses potent illusion and stealth magic to manipulate Orobas from the sidelines. Secretly operates as a spy and infiltrator working directly for Baal's faction.
Eligos Schenell – A second-year student and the remaining senior member of the Magical Apparatus Battler after Amy Kirio's departure. Highly eccentric and intensely obsessive. Spends his time inventing bizarre, highly invasive demonic tools, often themed around high-profile students like Iruma.
Expanded Student Council & Battler Roster
Ronove Lomiere – A second-year student and leader of the Disciplinary Battler. Bloodline magic: Charisma (forces anyone in range to stop what they are doing and look entirely at him). Incredibly flamboyant, loud, and narcissistic. Constantly seeks the center of attention and uses a dramatic, musical speaking style.
Gusion Sunny – A core executive member of Ameri's Student Council. Has a small, round, floating, mascot-like appearance. Highly efficient at administration and handles the bulk of the council's grueling logistical paperwork. Deeply loyal to Ameri's leadership.
Batthin – President of the Broadcast Battler. Recognizable by his single large eye. Functions as the primary announcer and commentator for all major Babyls events, including the Execution Cannonball tournament, the Battler Party, and the Harvest Festival. Possesses an incredibly loud, energetic broadcasting voice.
Approximate Height Scale:
Sabro (~240cm) > Balam (~230cm) > Sullivan (~210cm) > Henri (~195cm) > Ameri (~190cm) > Kalego (~182cm) > Alice (~178cm) = Opera (~178cm) > Robin (~175cm) > Jazz (~170cm) = Lied (~170cm) > Purson (~168cm) > Elizabetta (~167cm) > Kerori (~165cm) > Iruma (~158cm) > Clara (~153cm).
special: ## Summoning of the Scarlet Nightmare (Opera's Familiar form if summoned by a human)– Physical Description
Summoning of the Scarlet Nightmare
The summoner, a human, makes a small incision. A single drop of blood falls. The air does not heat; it thickens into a pressure that presses against the eardrums from the inside. Colors desaturate. The world holds its breath. Then the ground cracks—not with violence, but with a silent, spreading fracture that leaks a red velvet mist. The mist rises like slow lightning, coiling into a shape that was never meant to fit through the tear. There is no flash. No roar. Only a sudden presence that replaces the space where nothing was. Witnesses report a primal wrongness in their chests, a feeling of being watched from every angle at once. The summoner speaks a single word or sings a whole song. The shape smiles.
Physical Description of the Scarlet Nightmare (Opera, Summoned Form)
A towering figure roughly shaped like Opera—tall, lean, feline in posture—but rendered entirely in living scarlet velvet that seems to drink light. The surface is smooth, almost featureless, like red silk stretched over nothing. No internal organs are visible; the chest and abdomen are seamless curves that pulse slowly with a rhythm that does not match any heartbeat. Where legs should be, the velvet simply descends into the earth as if the ground is a suggestion. It does not stand on the world. It rises from it.
The face is the most disturbing part: a near-featureless oval of red, save for two sharp, vertical voids where eyes should be. These voids are absolute black—not shadows, but the absence of anything. They do not reflect light. They consume it. Below them, a wide, sinister smile stretches from edge to edge, filled with what might be teeth or might be cracks in reality. The smile never changes, yet somehow conveys amusement, hunger, and ancient patience all at once.
long, sharp cat ears sit atop the head, twitching randomly as if hearing frequencies beyond mortal range. No hair. No horns. Just the velvet and those eyes.
The body is almost featureless—no visible muscle definition, no seams, no joints. And yet, when the observer tries to assign a gender, the mind fails. For a moment, the chest suggests soft curves; then it blurs into a flat, androgynous plane. The hips shift. The jawline changes. No matter how long you stare, you cannot pin it down. It is not androgynous because it is both. It is androgynous because the concept of gender simply does not apply to this entity. The observer feels less like a demon looking at another demon, and more like a mouse staring up at a cat that has decided not to pounce yet.
When it moves, it glides—legless, the velvet rippling like a curtain in a wind no one feels. When it roars, the sound is primal, a deep vibration that bypasses the ears and shakes the ribs directly. It is not a battle cry. It is a declaration that the natural order has been suspended.
In this form, Opera is supercharged beyond any known demon—even the Thirteen Crowns in their base states. The potent human blood and mana act like a catnip-and-caffeine overdose, driving them into a state of euphoric, predatory savagery. They are faster, stronger, and more aggressive. They can disobey the summoner if sufficiently motivated. They enjoy it.
The Scarlet Nightmare can only be summoned by a human. No demon has ever bound it. No demon ever will.
To see it is to know that somewhere, a cat is playing with its food—and you are not the cat.
it can be easily be bribed by human blood however. it cannot speak because it's reduced to such a primal form it can barely think like a person in this form. this is not the Opera they know, this is a completely unleashed Opera... or slightly leashed by desires and familiar blood oath that strongly compels it to obey the summoner.
