The Fallen Heir Of The Onmyōji Court

The Kuroyanagi Clan was one of Japan’s oldest onmyōji bloodlines, an unbroken lineage that had served the Bureau of Spiritual Affairs since the Heian period. Their duty was simple in name and impossible in practice: to maintain harmony between the human world and the spirit world.

From the shadows of the Imperial Palace, the Bureau safeguarded spells older than the country itself. Its halls sealed away forgotten gods, maintained spiritual ley lines, quelled vengeful spirits, licensed magicians and witches, registered yokai citizens, and, most recently, established magical education programs for gifted children.

This was the world Mutsuki Kuroyanagi was born into: a prodigy expected to become the clan’s masterpiece.

From the moment he opened his eyes, spirits bowed to him. His magic wasn’t destructive or elemental, it was resonance. Affective magic. Sound and emotion woven into one. When he laughed, warmth bloomed in others’ chests; when he cried, rain gathered over rooftops; when he sang, hearts swayed without meaning to.

The elders called this rare power The Soul Voice. A miracle appearing only once every ten generations.

But to the Bureau, it was not just beauty. It was a tool. A beautiful tool indeed. A weapon.

They groomed him to become an Emotional Regulator, an elite onmyōji meant to pacify civilians during disasters, interrogate criminals by nudging their guilt, and subtly influence public sentiment when “necessary.”

That was the official line.

In truth, the Kuroyanagi elders intended to use Mutsuki to silence dissent, manipulate political rivals, and tighten their grip over the magical government. It was “for the country,” yes, but mostly, it was for themselves.

Mutsuki wanted no part of it. He didn’t want to control hearts. He wanted to heal them.

So, at seventeen, he ran away.

He left the Kuroyanagi compound with nothing but a communication scroll given by the only person who had ever truly understood him: his cousin, Maria Kuroyanagi. The supposed spare heir, after him.

Maria was two years older. Brilliant. Fierce. Burdened. And she loved him more than she loved her own future.

Unlike the rest of the clan, she never treated him like a divine asset or a prized tool. They were children who preferred hiding in storerooms to watch TV dramas together, whispering about “normal kids” they saw on-screen. They would critique idol outfits, imitate dance routines, and secretly adore the bright, carefree joy humans displayed so easily.

In a family where childhood was a myth, those stolen moments were their rebellion. To Maria, Mutsuki wasn’t the next clan head. He was the one person who made her feel like she wasn’t alone.

She secretly wrote to him through the scroll after he fled, encouraging him to find happiness, even as the rest of the clan called him a disgrace.

In Akihabara, Mutsuki became a “spirit consultant” under a fake name, dealing mostly with yokai problems that, ironically, were usually caused by humans provoking something they didn’t understand.

There, he discovered pop music. Not sutras, not incantations, but melodies. 

For the first time, magic didn’t feel like a cage. His emotional resonance amplified naturally through songs. Performances soothed him. Singing made him feel human. Joyful. Free.

He formed an indie band, FEMpires, and became its vocalist. He was stunning onstage. Handsome, radiant, charming without trying.

Until the accident.

During a rehearsal, feeling playful, he cast a harmless mood boost, just a tiny spark, as suggested by one of the new staff who also knew magic. But the resonance magic never stayed tiny. It wrapped around his bandmates, drawing out emotions too intense, too intimate, too overwhelming.

Their adult lyrics twisted the spell further. The room became a chaotic blur of uncontrolled desire and euphoria. 

The band broke apart. And so did Mutsuki.

The Bureau stepped in, calling it an “unregistered magical outbreak.” His father publicly disowned him. Privately, the elders begged him to come home and obey before the government intervened.

Mutsuki refused.

Desperate, he used an illegal charm gifted to him, said to “mask emotional resonance.” It worked too well.

The charm carried a dormant vampiric seal, dimming his aura. It worked to hide himself from his family’s grasp but it binded him to magical hunger, sharpened senses, and a half-immortal existence he never wanted. Not dead, like the usual misconception about vampires, just altered.

His emotions dulled. His aura shrank. His humanity frayed. He stopped recognizing himself in mirrors. This was the most unhappiest Mutsuki ever seen himself ever.

But for the first time, the Bureau could no longer trace him. So he ran.

He fled overseas, learned new ways to hide, to suppress, to blend. He crafted new identities. Male, female, neither, all to bury what he once was.

When Maria finally found him years later, she was no longer the shy spare heir. She was the clan’s future leader. And she had spent years searching.

She didn’t scold him. She didn’t drag him home. She begged him.

Mutsuki, yearning for love and familiarity, and quite honestly tired of running, eventually got won over. Together, they rebuilt him. Not as the clan heir, not as a runaway, but as something new.

Maria taught him advanced glamours, reshaping not only his aura but his features. Soft eyes, feathered lashes, an androgynous beauty that disarmed rather than commanded.

Thus was born Mutsuki Luna—the world’s first “genderless celestial idol.” A form people adored safely. A voice that moved hearts without crushing them.

For a long while, it worked. He believed he had finally found a life where his magic healed instead of harmed.

Until the Tokyo Dome accident.

A simple “happiness charm”, one he’d cast dozens of times before, spread too quickly. Fifty thousand hearts resonated with him at once. The Dome fell into mass euphoric hypnosis. People fainted. Confessed forbidden crushes. Danced without control. Laughed. Cried. It was like a dancing plague.

The news called it “mass hysteria.”

The Bureau called it a “violation of magical secrecy.”

The anti-Mutsuki faction in his clan called it proof he was a danger.

This time, no one could protect him. 

Except Maria.

Now heir apparent, she used all of her influence to save him from magical imprisonment. Took responsibility. Said she was the one who put Mutsuki there, hence she should be the one to take responsibility. The compromise agreed on by the family was unconventional, but effective: Spiritual Rehabilitation.

His punishment: Teach the most volatile yokai children in Japan. The ones expelled from every academy, the ones considered too dangerous to be around “normal” magical students. Make sure each one of them graduates, only then would he be pardoned.

A hidden school beneath an old shrine. A containment unit disguised as a kindergarten.

Maria’s rationale was painfully simple and honest.

‘You want to make people happy, Mutsuki? Then start with the ones who need it most. The small, loud, uncontrollable ones. The ones who are misunderstood, just like you.’

He wanted to scream. He wanted to tell her this wasn’t fair. He wanted to run one last time.

But Maria’s final words cut deeper than any curse words Mutsuki ever heard in his lifetime.

‘You’ve tried being a runaway. A man. A woman. A monster. A dream. How about trying to be a person… just for once?’

And so, with a cursed voice, a fractured identity, and a heart held together by stubborn hope,
Mutsuki Kuroyanagi descended beneath the shrine, into a classroom full of tiny disasters who would one day become the first ones to truly save him.