The soul is the final wall.
Neither time, nor pain, nor executioners can break it.
But whoever claims it demands a price:
will you be the one to escape, or the one consumed by its fire?
It was three in the morning on a night shift. I stared intently at the cardiac monitor of a patient in intensive care from the nursing station computer.
Because of his illness, he was sedated, deeply asleep, connected to a ventilator that allowed him to breathe without pain or anxiety.
I watched the numbers on the monitor change from time to time: the rhythm of his heartbeat, the oxygen in his blood, his blood pressure, his breaths, and his body temperature. Each variation triggered an alarm that shattered the silence of the night.
All those readings confirmed that the patient was in critical condition, and at any moment everything could change—his soul might leave his body. At least during my shift, I didn't want anything to happen.
—The patient isn't going anywhere yet —Tomás, my companion on that cold night, told me—. Stop staring at the monitor so much, you'll jinx yourself.
—The rhythm and heart rate are quite unstable, I'll go check —I stood up and walked to the cubicle just a few steps away—. I hope it's only a loose electrode.
Don Guillermo's eyes were wide open, as if he had just woken from a nightmare. I approached and held his hand.
—Everything will be fine, Don Guillermo. Try to rest a little, I'll check your equipment.
I carefully examined the electrodes attached to his body. Nothing seemed wrong. I gently closed his eyes and stayed for a while, speaking to him as I adjusted the rest to make him comfortable. Even sedated, I knew he could hear me.
I returned to my seat and let out a tired sigh.
—What do sedated patients dream of? —I asked, more to myself than to Tomás. At those hours, the strangest conversations became part of the routine.
Tomás looked at me, puzzled, and let out a small laugh.
—Who knows. They say sedated patients can't dream. Why do you ask?
—I suppose Don Guillermo had a nightmare. He looked frightened.
—Could be. We don't know what they dream.
—You're right —I shrugged and leaned back a little at the desk.
But I wasn't sleepy enough, and I couldn't allow myself to rest even for a moment. A life still depended on me.
—Ah…
I don't know why that conversation stayed with me, returning to my memory at this very moment.
The last thing I remember before sleeping was being in intensive care. Was I sedated too? Did I ever open my eyes with that same look of terror?
I turned in bed, staring at my reflection in the mirror hanging in front of me. I had placed it there in the hope that, upon waking, I would see my own face and not Kuroha's—that I would be in my room and not hers… that I would be home… and that my mother would greet me with a smile.
I hardly slept, except when a mission left me exhausted. On peaceful nights like this, insomnia was my executioner.
The moon watched me through the window, relentless, as if it were my judge.
I tried not to think too much and closed my eyes, wishing this torment would end.
I had read many isekai, but none mentioned the physical pain or the sacrifices required. Most of them died and reincarnated, or were transported completely. Rare was the one who suffered real wounds… well, perhaps in Sword Art Online, but that was augmented reality.
I let out another weary sigh. Each time, Yamikiri lost more control, becoming more savage and violent.
In the last battle with my classmates, she completely ignored that I had fractured my arm and kept fighting as if nothing had happened.
Luckily, here there were reverse spells for healing. Otherwise, that fracture surely would have ended in surgery…
But I wasn't sure if my real body had been affected.
I stared at the ceiling with a vacant gaze, as I usually did. I no longer bothered to check the time on the clock; the passing of hours had become indifferent.
The phone they had given me rang. I picked it up lazily and looked at the name on the screen.
Mom.
With everything that had happened, I had forgotten to call her. She must have been worried about me. I answered without much thought.
—Hello, mom —it felt strange to call someone that way.
—Kuroha! I was so scared because you hadn't called… I thought your father had done something to you…
He entered the small room, and with his mere presence the atmosphere grew heavy. He walked to my chair and sat in it. With a gesture of his hand, he ordered my mother to serve him tea. Nervously, she began to pour. I tried to protest, but my mother shook her head.
—The higher-ups want to evaluate his effectiveness as a vessel. They plan for him to devour all the fingers before killing him along with Sukuna. My duty is to watch over the boy —I said, crossing my arms over my chest and never breaking eye contact with my father. Inside me, Yamikiri roared, and I struggled to keep my mind clear.
—I see… and Satoru Gojo?
—What does he have to do with this?
—Everything. They must know that the Mizuki family is the most powerful, the only one capable of killing that monster… or mastering it.
—What? —I asked, confused.
—I've sent people to watch you, to make sure you didn't make mistakes. They've noticed very interesting things about your interaction with that boy.
—What are you implying?
—Nothing in particular. I'll just give you a simple order. —He stood and placed himself before me—. Do whatever it takes to ensure that monster destroys Satoru… and you claim the glory of killing Sukuna. You will deliver the final blow with Yamikiri.
—… —I was in shock at his words.
—Don't look at me like that, child. Think of it as avenging the first Patriarch. —He patted me on the head before heading for the door—. I expect results soon.
When he disappeared behind the door, the silence was infernal, as if his presence still clung to the place.
—My Kuroha… —my mother broke the uncomfortable silence, stood, and rushed to embrace me—. Everything will be fine. If you don't want to do it, don't. I know you've grown fond of Gojo-sensei and that boy…
—It's all right, mother. You don't need to tell me. At some point it will happen, and I won't be able to stop it… but I don't think I can do what father asks. I can't allow someone to end…
—No, I know you can't.
—I'll go find the Master of the Cracks. I want to speak with him before I leave.
—Take care, daughter. Yamikiri will always be at your side to protect you. You can trust her —she told me with an innocent smile.
Yes, of course… protect me. But she doesn't know. She trusts Yamikiri far too much to ever doubt her.
—Thank you, mom. I have to go. I love you. —I left the room and set out to find the Master of the Cracks.
I walked through the corridors of the house aimlessly, until I reached near the training hall.
—It seems you were looking for me. —The Master of the Cracks appeared behind me.
—Hello, master —I bowed respectfully before him, but he looked at me with confusion.
—Child. I've known you since you were born… and there is something different about you. —He observed me with suspicion—. Even your bond with Yamikiri, once perfect, is broken. And the marks you try to hide… are as clear as water to my eyes.
I looked at him, bewildered. How could he possibly see the scars on my chest?
—Ah… —he raised his hand in a gesture of silence.
—Tell me, little traveler of time… what awaits you here?
—What!? —I cried, stepping back.
—I have already introduced myself to you as the Master of the Cracks, haven't I?
—Yes… but I… I wrote you…
—Are you sure? —he walked around me, studying me closely. I was left speechless.
—Eh… —desperate, I began to rack my brains, trying to remember when I had ever thought of that character. I knew Kuroha would have a master, but… wasn't it supposed to be her mother who trained her? I lifted my gaze to the man before me, staring at him in disbelief.
—I don't believe you… I think not… You weren't in the original story! —he nodded, satisfied with my answer.
—Just like Yamikiri, your connection with the moon called me, and that is why I appeared before you. You are not the first traveler to be summoned into a story.
—… —I looked at him, confused, unable to say a word.
—But traveler, tell me… what confuses you? Your heart, once energetic and brave, now hesitates. That is why your bond with Yamikiri is weak and uncertain.
—Ahm… well, considering that I could die… the story I'm in tends to be very bloody. The villain is far too focused on me, and the line of the story I was creating was cut off. I no longer have control over it…
—Is that all?
—Eh… yes. Was I supposed to say more? —I answered sarcastically. The Master of the Cracks only smiled.
—You are the protagonist of your own story. You can reshape your character however you wish. You don't need to dwell on such things.
—You're right… I forgot something else. I have no idea how to fight. Kuroha was good at it, so she never had to worry…
—And what if you tried to connect with the character?
—Connect? —I looked at him, confused. He watched me patiently, waiting for me to analyze the situation myself.
—No one knows Kuroha's abilities, emotions, and feelings better than you, the writer. Have you realized that no one has suspected you are not the original Kuroha? Because for you, it is as natural as breathing to assume her role… except in battle. You resist hurting yourself, when in truth no one knows Kuroha's fighting style better than you.
At last, I understood what he was trying to tell me.
Kuroha had been designed to be a strong, determined, and brave protagonist, almost to the point of recklessness. Yes, she would also have moments of frustration and despair, when everything she believed in collapsed and the cracks in her chest grew deeper each time she lied to protect Yuji Itadori.
But unlike me, she never faltered in her abilities. She always trusted them and improved, as any true protagonist would.
I looked at the Master of the Cracks, confused, a knot tightening in my throat.
—I can no longer give you more lessons. From here on… —his voice broke into an echo, as if it came from the cracks themselves.
His figure began to fade, leaving me with more doubts than answers…
—Wait! —I ran toward him, trying to reach him, but he vanished before my fingers could touch him.
I let out a sigh and began to walk aimlessly, the words of the Master of the Cracks still echoing in my mind.
No one knew Kuroha better than I did: her personality, her abilities, her past, her present, and her future. She was everything I was not… If my insecurity and fear had caused Yamikiri to change, then the only solution was to connect with Kuroha's soul.
Determined, I ran to the train station. One of the places where Kuroha had once unleashed her powers… the cemetery of her first mission, where countless cursed spirits awaited.
As if answering my soul, Yamikiri began to throb violently, as if shouting: "Yes, let's go!"
I waited patiently as the scenery shifted. I stepped off the train and took a taxi to the cemetery. Just as I had imagined, since it was a place I had written before, it remained intact, suspended in time.
The moment I stepped inside, everything changed: the sun vanished, replaced by a blood-red moon. The clear blue sky turned into a pitch-black void, like the mouth of a wolf.
The curses emerged, ravenous and restless… waiting for me to make the slightest mistake.
What would Kuroha do in this moment? No… what should I do?
—Give me the crimson of your blood —I whispered, biting my finger until a drop fell. With it, I drew a symbol across my chest—. With it… cut through the deepest darkness.
Yamikiri burst forth, radiating a terrifying light, almost alive: pure white streaked with black and violet. Her chains swung freely in the wind, chiming rhythmically with each of my movements, as if rejoicing.
I forced myself to think like Kuroha. I stepped forward slowly, then broke into a run, raising Yamikiri high. She responded eagerly to my newfound determination.
The curses lunged, shrieking.
—Lullaby! —I cried, slashing through them. Heads rolled at my feet, blood splattering across my face.
—Dance of the Dead! —I spun, Yamikiri's chains extending like whips, ensnaring several curses and tearing them apart in a burst of violet light.
The ground trembled beneath my steps. Each strike echoed like thunder in eternity. The curses multiplied, but Yamikiri grew lighter, freer, as if delighted to fight alongside me… with me, not with Kuroha.
I leapt forward, cleaving through a creature with a clean strike. Another lunged from the shadows, but Yamikiri's chains coiled around its neck, dragging it toward me. With a swift motion, I severed its head.
The blood moon illuminated the battlefield. My breath was ragged, but my spirit burned.
What would Kuroha do? The answer was clear.
Fight. Without restraint.
Yamikiri pulsed in my hands, light and alive, rejoicing to be with me… not with Kuroha, but with me.