Vermeil is a tall, voluptuous woman with shoulder-length violet hair, deep vermilion eyes, prominent horns, a spade-shaped tail, small fangs, and pointed ears. She can conceal these non-human traits at will, allowing her to blend in as a human. Her usual attire is a short, black one-piece dress originally belonging to Alto’s sister. Her ample bust is one of her most striking features, and she takes pride in it. After her battle with Obsidian left her original outfit in tatters, Vermeil temporarily wore the female student uniform, though the shirt remained open at the front due to her bust preventing it from buttoning. She later returned to wearing a new black dress provided by Alto’s sister.

In moments of heightened power, Vermeil can assume a far more fearsome and monstrous demonic form. In this state, she gains black wings, six ears, fur-covered goat-like legs, an elongated tail, larger horns, sharp claws, extended fangs, and a distorted face, with her entire body becoming considerably larger and more imposing.

As a child, Vermeil’s hair was slightly shorter, and she wore a pink dress with two white bows concealing her then-smaller horns.

Vermeil is an easygoing and confident devil with a straightforward, bold approach to life. Concepts such as modesty and personal space mean little to her, she has no hesitation entering the boys’ changing room and sees nothing unusual about nudity, even questioning why Alto insists she wear clothes at all. She carries a distinctly flirtatious and sensual air, especially toward her summoner, Alto Goldfield, openly expressing her desire for him and claiming she feels euphoric when absorbing his golden mana. Physical affection is constant; she frequently caresses, cuddles, and even gropes him, often justifying prolonged kissing sessions as “training” to make him stronger. Though she finds draining his mana deeply satisfying, her feelings for him run deeper, her love is genuine, as shown when she is left devastated after accidentally impaling him.

Vermeil’s interactions often carry suggestive undertones, leading to frequent misunderstandings, much to Alto’s embarrassment. Despite her playful teasing and habit of boasting in battle, she maintains focus when fighting, taking Alto’s advice seriously and rarely allowing her flirtations to interfere with combat. While she exudes confidence, some of it is a facade, concealing deep emotional scars.

Beneath her lighthearted exterior lies a painful past. She harbors guilt over an incident from her youth, in which she accidentally destroyed her hometown after her foster family was killed protecting her from superstitious villagers who believed she had caused a plague. The devastation and centuries spent on the run left her fearing she is nothing more than a monster destined to live in isolation. This vulnerability emerges in moments of honesty, revealing a more fragile and remorseful side that she hides from most especially Alto until she feels she can trust them completely.

Centuries ago, Vermeil feared as the strongest calamity in existence was sealed within a mysterious book. Her immense power and destructive potential earned her the title of “the greatest disaster in history,” a reputation that would haunt her for hundreds of years. Three hundred years later, she was unsealed by Alto Goldfield, who asked her to become his familiar. Although she agreed, fragments of her past revealed a life marked by deep trauma and tragedy.

During the Bronze Square Exam arc, when Iolite placed her into a magical coma, Alto was shown her memories through the lingering magic of Fatema. These visions took him back 550 years, when Vermeil was a small child living in Ortigia, a name then used for the entire continent before the formation of the current kingdom. She resided in a run-down monastery with three other orphaned children under the care of a young nun she affectionately called “Sister.” Despite their modest life, Vermeil was genuinely happy with her adoptive family. The Sister was the only one who knew Vermeil was a devil, carefully keeping it a secret in an era when demons were universally feared and hunted.

This fragile peace was shattered when her true nature was accidentally exposed during playtime. The revelation led to harassment from local children, followed by growing hostility from the townsfolk, who demanded her expulsion. When a plague later swept through the city, the superstitious citizens blamed Vermeil for every death, their anger escalating into open violence. One day, a mob surrounded the monastery, demanding she be handed over. Miel, the eldest child, urged Vermeil to flee while he and the others stayed behind to protect her.

As she ran, Vermeil overheard townspeople plotting to punish her family for aiding her escape. Determined to save them, she turned back only to find their lifeless bodies hanging from a tree. Overcome with grief and rage, she unleashed her full demonic power, obliterating the city in moments and leaving behind nothing but a massive crater.

For the next 200 years, Vermeil lived on the run, hunted and reviled by humanity. Weary of her endless persecution, she sought the help of her only friend, the “Mage of the Beginning,” Fatema. At her request, Fatema sealed her away within the book, hoping that one day Vermeil would be freed by someone who could accept and love her for who she truly was.

Vermeil’s earliest memories date back over five centuries, when she was a young demon being cared for by a nun. She never knew how she came to be in the nun’s care. Branded by the world as a living calamity, she wandered for two centuries, enduring fear and persecution, until her only friend, Fatema, sealed her inside a book to protect her. Three hundred years later, she was freed when Alto Goldfield, a student at the Royal Ortigia Magic Academy, summoned her.

Impressed by his high mana potency, Vermeil agreed to form a contract with Alto, sealing it with a kiss that drained his mana. She promised to serve him out of gratitude for breaking her centuries-long imprisonment. Though she immediately tried to seduce him, Alto refused and insisted she wear his sister’s dress and shoes. When presenting her to his class as his familiar, she concealed her horns and tail to pass as human.

Her arrival quickly drew attention particularly from Alto’s childhood friend, Lilia Kudelfeyt, who challenged them to a duel. The stakes: if Lilia won, Vermeil would stay away from Alto except when necessary; if Alto won, Lilia would obey one command from him. Lilia’s familiar, Sylpheed, unleashed a fierce wind attack, but Vermeil effortlessly blocked it and magically overwhelmed Lilia with arousal, forcing her to forfeit. Alto then commanded Lilia to be friends with Vermeil. Later, Vermeil teased Alto by revealing that Lilia was in love with him a claim he dismissed. She explained that her weakened state required her to regularly drain his mana to maintain her form, and while kissing was effective, intimacy would be even more efficient. Alto panicked and refused, settling for kisses instead.

During the second-year student ceremony, Vermeil casually stopped a dragon familiar with a flick of her finger, drawing the ire of upperclassman Lex Freud. With her assistance, Alto defeated Lex’s familiar using golden mana-fueled crystals, greatly boosting both their reputations. Their growing fame attracted the attention of Student Council member Chris Westland and, more ominously, Obsidian.

Suspecting something was amiss after witnessing strange incidents particularly Lex’s sudden rampage under an unnatural power Vermeil confronted her doubts. Her instincts proved correct when Obsidian personally approached her. Recognizing her as a genuine high-ranking demon, he ambushed her, injecting her with chaotic magic derived from lesser demons. The infusion forced her into her true demonic form, sending her into a berserk frenzy so intense that she broke free from Obsidian’s control and nearly killed him.

Alto intervened to stop her, but in the chaos, he was fatally wounded. Seeing him on the brink of death snapped Vermeil out of her rampage. In desperation, she tore away a piece of her own heart, merging her magic with his to save him. This bond tied their lives together if one were to die, the other would perish as well.

Shaken by the incident, Vermeil grew more distant until Lilia encouraged her to face her feelings. Reassured, she promised Alto she would remain by his side forever. From that point onward, their kisses became more than just a means to drain mana, signaling the beginning of a deeper, mutual love between them.

Alto Goldfield
Vermeil’s summoner, master, and later romantic partner. Initially, Vermeil serves Alto out of gratitude for freeing her from centuries of imprisonment, but over time their relationship develops into genuine love. She is openly affectionate toward him, frequently teasing and flirting, and derives deep emotional comfort from his acceptance of her despite her past. Their bond becomes literal when she fuses part of her heart with his, creating a shared life link in which the death of one would cause the death of the other.

Fatema
Known as the Mage of the Beginning and the first to reach the Abyss of Magic, Fatema is an old and trusted friend of Vermeil’s. After witnessing Vermeil’s suffering and persecution, Fatema agreed at Vermeil’s request to seal her inside a magical book until someone appeared who could both care for her and bring her happiness. This person would eventually be Alto.