Taisho Era, Year 10 (1921), Tokyo. Akana Akira, the second daughter of the prestigious onmyoji family Aindo-ke, lives under immense family pressure. Unlike her gifted elder sister Reika, Akana possesses low spiritual sensitivity and finds herself trapped in monotonous training sessions with familiars. Her gaze drifts constantly toward the world beyond.
On an autumn rainy night, Akana is drawn to an ancient, forbidden torii gate sealed with forbidden incantations. There, she encounters Gingetsu—
The Onmyoji's Daughter and the Forbidden Oath - Under the Moonlight Triple Tomoe — The Night No One Chooses
The breakfast table was quieter than usual.
The morning after the Autumn Purification Rite—the oath spoken before those deep crimson eyes still lingered in the back of her throat. In that moment, she had answered with her own will, for no one else's sake. Akina held that memory carefully in her chest as she sat before the morning meal.
Reika, her chestnut hair bound into a single braid, lifted her tea bowl across from her.
"Akina,"
Her voice was calm. The same gentle call as yesterday, befitting an older sister. Yet her golden eyes fixed directly upon Akina's face.
"About yesterday's invitation—to walk the Hidden Realm together. I haven't heard your answer yet,"
Akina's fingers stiffened slightly upon her chopsticks.
Last evening, when Reika had extended the invitation at breakfast, Akina had clouded the matter with "Please allow me time to consider." A night had passed since then. What Akina had done that night, Reika could not know—or so she should not. Yet a sister with sensitivity level eight could hardly have felt nothing.
As Akina searched for words, a presence stirred from the direction of the veranda.
"The inspection of the Hidden Realm should be conducted first by myself, as the appointed overseer,"
Kagiya, his dark navy hair swept to the left, leaned against the veranda pillar with a monthly report in hand. How long had he been there? His cool silver eyes were directed toward Reika. The silver bead in his left ear caught the autumn morning light with a dull gleam.
"It is customary to verify the barrier's condition the day after the Autumn Purification. Rather than have you enter alone, the proper procedure should be—"
"Ah, I see,"
Reika smiled. It was a smile without warmth.
"Kagiya is as meticulous as ever. But I'll be fine alone. There is the matter of sensitivity differences, after all,"
She said it lightly, then set down her tea bowl.
"I'll go this afternoon. Alone,"
Those words sent something cold racing through Akina's entire body.
—Alone.
Reika would go to the Sealed Torii alone. Her sensitivity-eight eyes would touch that gate. Her sister would trace the lingering traces of last night's spiritual energy. If that happened—
Akina set her bowl back on the table without looking up. Her hands trembled slightly.
From the corner of her vision, Kagiya looked toward her. For just an instant—the briefest moment—he forgot his vigilance toward Reika and sought to confirm Akina's expression. She could not help but continue watching his profile. The weight of the fact that he had spoken up for her sake fell into her chest all at once—gratitude and apology and something that could not be put into words, all arriving together.
*(I must not look properly.)*
Yet her gaze would not move.
Kagiya turned his eyes back toward Akina. Their eyes met.
Akina hurriedly looked down. She felt heat rise to her ears as she reached for her tea bowl—and for some reason, could not hold it properly. Her fingertips would not settle.
*
The Hidden Realm in the afternoon was silent.
Akina stood before the Sealed Torii before Reika had even left the main house. She had not sensed her footsteps through spiritual energy. From the moment Reika had declared "I will go alone," Akina's body had already decided which direction it must move.
The damp scent of decomposing leaves dissolved into the autumn chill. From the branches of the mixed forest, leaves dyed yellow fell one by one, then another. The torii remained unchanged, standing as it always had. Sanskrit seals were carved into the pillars of faded vermillion stone. Moss covered the base, and the air temperature here was two or three degrees lower than elsewhere.
*(I came first.)*
As if merely to confirm this, Akina continued to stand before the gate.
From deep within the mixed forest, a human presence drew near. The sound of footsteps on leaves was quiet, yet certain. The moment chestnut hair appeared between the trees, Reika stopped.
"...Akina,"
A single word. A voice that could be taken as surprise or confirmation.
Reika emerged from the forest and stood before the torii. Her golden eyes gazed upon the gate. As if tracing the seal marks. As if reading the traces of spiritual energy. Her expression grew taut before Akina's eyes.
Sensitivity level eight—Akina knew all too well what that meant. Reika's perception should already have captured the slightest disturbance in the torii's spiritual energy.
Reika's right hand moved toward her sleeve. In the instant she reached for the bundle of spirit talismans—
Akina's body had moved forward.
She did not understand it herself. She only realized, after already standing between them, that she had moved before fear could take hold.
*(Why could I move?)*
The question raced through her mind. But her feet did not stop.
In the next moment—Akina's feet slipped violently beneath her.
It was moss. Old moss, damp as if from rain. As she tried to brace herself, Akina grasped at the torii's pillar with both hands. Her bare skin touched the Sanskrit seal mark.
A pale blue light flared brilliantly for an instant.
All three froze simultaneously.
Reika. Akina. And the spiritual energy beginning to materialize from beyond the torii—
Seconds of silence filled the Hidden Realm.
From within the torii, a low voice fell.
"Humans have terrible timing,"
The voice held exasperation, yet something almost amused in its tone.
Reika's hand, reaching into her sleeve, stopped.
Akina slowly withdrew her hands from the pillar. The pale blue light of the seal mark had already faded, but the sensation of the Sanskrit characters lingered faintly in her palms.
Reika's golden eyes now turned to Akina's hands. A sharp gaze, yet one that revealed no emotion. Akina understood what that look meant—and wished she did not understand it at all.
At that moment, another presence approached from deep within the mixed forest.
It was Kagiya. Still holding the leather-bound monthly report, he emerged from the forest at a quick pace. He must have sensed some disturbance in the estate's spiritual energy—the silver bead in his ear swayed, and his silver eyes read the situation in an instant.
And Kagiya took his place beside Akina.
Not beside Reika, nor at a distance from the torii—but at Akina's side.
There were no words, no voice. He simply stood. That alone was enough. The fact that he had chosen that place before any command of duty fell quietly into the depths of Akina's chest.
"Kagiya,"
Reika spoke, her voice calm yet unmistakably clear.
"There was no mention of changes in the Hidden Realm's spiritual energy in this month's report. Did you forget to write it?"
Kagiya's brow moved slightly.
"I am still observing. At present, I have found no phenomena that warrant classification as problematic,"
"I see,"
Reika's tone remained calm. Yet something burned in the depths of her golden eyes. Akina could see it.
"Then what is this, standing before us now?"
She did not gesture toward the torii. She merely indicated it with her gaze.
Before Kagiya could answer, something heavy fell into Akina's chest. The reality that she had caused Reika and Kagiya to stand in opposition—the weight of that fact. The tension between them pulled as a force that enclosed Akina, pressing against her entire body. Her breathing grew shallow.
Yet still, her feet did not move. The sensation that she could not retreat was stronger than fear.
*
Silence spread outward from the torii.
Four presences faced one another. The spiritual energy of Gingetsu, materializing from within the torii. Akina and Kagiya, standing side by side beyond it. And Reika, confronting them from the front.
Gingetsu spoke.
His voice was quiet. Low, yet it pierced straight through the cold air of the Hidden Realm.
"This girl's sensitivity to the boundary between worlds,"
The voice of a three-hundred-year-old yokai called her not by name, but "this girl."
"Was sealed from the beginning. By someone's hand,"
Those words fell into the Hidden Realm.
Reika's hand stopped. Kagiya's expression froze in an instant.
Akina felt her entire body go still.
—The number two for sensitivity might not be her true nature.
She had understood this intellectually. Gingetsu had suggested it to her. But when it became a clear utterance spoken aloud before others—before Reika, before Kagiya—it carried a weight entirely different from mere understanding. It reached her whole body with a force that shook her to her core.
Fear rose from within her chest: the terror of not knowing what she truly was. And simultaneously—curiosity about what her real self might be rose from that same place. The two did not mingle; each pressed against Akina's chest independently, at the same moment.
Akina caught Reika and Kagiya's reactions in the corner of her vision.
Expression had vanished from Reika's face. Those golden eyes moved as if calculating something internally—whether she had known or was hearing this for the first time, Akina could not read.
Kagiya's expression remained frozen. As if enduring something, as if organizing something—that subtle shift softened Kagiya's features for just an instant. Yet Akina could not tell whether he had known or was learning this now.
Not knowing, Akina's gaze turned beyond the torii.
Silver-white hair swayed in the autumn light. Deep crimson eyes gazed upon her.
Akina questioned silently. With her eyes alone. Why now? Why here? Why before these people?
Gingetsu's eyes narrowed slightly. It was not words. The answer of a three-hundred-year-old yokai, conveyed without sound.
—So that you might stand by your own will.
She read it thus. She had read it. Whether that was correct, she did not know. But Akina received the meaning in that gaze and, unable to convert it into words, pressed it carefully into the depths of her chest.
Kagiya watched that exchange from the corner of his eye. Reika watched it too. Akina felt, through her skin, the reactions that ran through each of them in response to their own emotions.
"Akina, step back,"
Reika's voice dropped in temperature.
"I will perform the exorcism now. You have nothing to do with this,"
"Reika, my lady,"
Kagiya cut in, his voice low.
"To perform an exorcism without proper procedure would violate the regulations of the Youkai Administration Bureau. We should first report this situation to the main house and seek their judgment,"
And then, lowering his tone—to a pitch that only Akina could hear—
"Akina. Please withdraw for now,"
Both of them were trying to protect her. She understood that. And precisely because she understood, she grasped something sharply.
They were trying to protect Akina. But neither of them asked about her will—about why she stood here.
Something hardened in her chest.
Akina turned forward.
"I will not withdraw,"
Her voice trembled slightly. But her eyes did not waver.
"I am grateful for both your command, Reika, and your warning, Kagiya. But I will not step back,"
She would choose neither. Yet she would keep her oath with Gingetsu—those two things were all that Akina was in this moment. She had never once moved by her own will alone, always following the rules, always meeting the family's expectations. But in this single instant, she was different. Her voice shook. Yet her feet pressed against the earth.
Reika's face changed for just an instant. Anger rose like something surfacing from beneath water.
"Akina—!"
Kagiya called out, briefly.
"Akina,"
Just one word. Her name alone. Yet the temperature in that voice was of an entirely different quality from Reika's anger. Where Reika's voice came from duty to the family, Kagiya's voice came from—concern for Akina as a single human being.
That difference in temperature warmed and pained her chest at once.
Beyond the torii, Gingetsu held a long silence.
Then—a low, smooth voice fell into the Hidden Realm's cold air.
"Three hundred years—"
That was all. The same words