Disclaimer: I do not own Sekiro: Shadows Die Twice nor do I own Demon Slayer: Kimetsu no Yaiba. They belong to their respective owners.

A/N: The title translates into Ensa no Kokyū, which supposedly means Breath of Hatred, but I'm not a Japanese speaker/writer nor am I weeb enough to claim I know moonrunes, so sue me. I'm just working with what I can get from both sources' wikia without relying too much on Google Translate.


怨嗟の呼吸


Much time has passed since Ashina has fallen.

I do not remember how long it has been since, only that it has been long enough. Memories come and go like blossoms from a cherry tree branch, lingering only long enough to be appreciated until one day, it is gone like all the others. The lands change. The rivers flow elsewhere. The people are different. The gods return and leave as whimsically as they please.

Yet… there are only some things I remember. Some more vividly than others.

Two figures immediately come to mind. I cannot remember their faces anymore but I know they were important. Them to me or me to them, I cannot say. I wonder how they are? Have they been eating well? Are they alive? Are they happy? Have they found fulfillment?

I suppose it does not matter. They would not bear to look at me as I am.

And then there is Shura. Shura… the word means nothing now but still it persists in my head, as if it is a purpose. Am I Shura? Am I looking out for Shura? Am I supposed to look up to Shura?

Nothing comes to mind. Only flames. So much flames. So much it can drive humans insane.

And the last thing. It is the one thing I remember so clear that it makes my heart ache akin to betrayal… or is it longing? Sorrow? Joy? Which one is it?

It is a wolf. A wolf and a little one who looks up to him.

But… who is he? Why is he the one I remember so clearly after all these years?


In a secluded location, known only to a select few, three individuals arrived from three different entrances. It was not just a tradition for entry to be different for different people; it was also a safety precaution for both the arrivers and the carriers. Even the scant few who know of this area were a deliberate decision.

For it was the homebase of their beloved oyakata (boss): the manor of the Ubuyashiki Family.

Upon the back of each of these individuals' uniforms was one kanji representing their mutual goal towards all of their enemies:

Metsu (Destruction)

"Flame Pillar." The masked one greeted.

The first to arrive was the Water Pillar. His face obscured by a red tengu mask, he donned an aesthetic water-patterned haori over the standard uniform of the Corp. His hair was cut short, beginning to show signs of graying, and a Nichirin blade hung at his hip.

"Water Pillar!" The addressed inclined his head vigorously. "It's been long since we last met! How many months does it make now?"

Like the Water Pillar, the Flame Pillar wore a haori layered with flame motifs everywhere over his uniform with a Nichirin blade hanging on his hip. Unlike the Water Pillar, his hair was as flames, unruly and wildly grown out and tied clumsily back behind his head, and he sported a cocky expression that was seemingly well-deserved for one in his station.

"Not months. Five weeks, not counting our last meeting. I see you have been adjusting well to your position. And with a child on the way, too."

The Flame Pillar laughed loudly. Proudly. "I have much space to grow into, no doubt! And please, contain your excitement, Water Pillar! If I was not keen enough, I would not notice that you are jealous of my progress! If I am to falter, it will only be because Ruka has fallen ill. And she is a strong woman!"

"I can see that." Even with the sullen-faced mask hiding his face, the Water Pillar could be felt smiling.

"And I'm fine as well. Thank you for asking." A snarky voice made itself known.

The third one approached the two.

"Roaring Pillar!"

"Kuwajima."

"That's Kuwajima-senpai to you, Urokodaki! Bah, I see kids these days have no respect for the elders."

Contrasting the two, the Thunder Pillar – far more known as the Roaring Pillar – forwent placing his Nichirin blade on his hip and hung it on his back instead. Like the other two, he sported a haori over his uniform that distinguished him apart from the others, one patterned with triangles reminisce of lightning.

"You're not that much older than us!" Flame Pillar stated loudly with laughter. "Perhaps by a few years, give or take. Is your back starting to kill you already?"

"I still hold seniority over you, so give some proper respect at least, Rengoku!" Kuwajima had a tick mark at the blatant rudeness.

Flame Pillar continued to laugh infectiously.

It was unprecedented for the Pillars to convene outside of being called together by the Ubuyashiki patriarch. Usually, they would only convene because the Boss called them together. Outside of that, it was considered abnormal for more than two Pillars to be in each others' company.

Because of that…

"Enough pleasantries. We all know why we're here," Urokodaki stated.

The lax mood came to an end and reverted to grimness. The three Pillars discarded their frivolity and returned to a professional persona. Their expressions were not dissimilar to veterans once more confronted with their past horrors.

"It's the fourth time in these three months. Perhaps it is still a coincidence, but I believe we are seeing a pattern." Flame Pillar's smiling visage was replaced by a bristling frown. "I do not like the thought and I would rather it be a mere coincidence… but I believe the change amongst the Kizuki (Twelve Moons) began this occurrence in our ranks."

"And what basis do you base this on, Rengoku?" Urokodaki tilted his head in curiosity.

"One of our own defected to the Demons, Urokodaki," Kuwajima noted somberly. The bitterness and regret in his voice brought their anger down enough to hear the Roaring Pillar out. He sighed harshly. "Immature brats like to prove their worth and status, and that just makes it all the easier for them to fall. Impatient, impulsive, insecure, they take that shortcut and throw away their heart and soul like that…"

"Kuwajima."

"…Enough." The eldest of the Pillars shook away the sorrow. It was not yet time to mourn. "They may not have been under me, but the price of defection must be paid by someone."

Said price did not need to be said among them.

Rengoku growled at the memory. He had been there. He had been the one to fell his blade. A friend. An ally. Someone he laughed with and ate besides during their training years. Now dead, because one of his brats decided not to wait for his potential to blossom. Seduced, and given in to the allures of a Demon. There was no pain even as his friend plunged the knife into his belly and to the side. The face of sorrow and disappointment remained even after his head fell from his neck.

How many cultivators have lost their lives to the Demons? How many more of their own will defect?

The thought was overwhelming.

"And so, this cannot continue."

A new voice weaved itself into their midst. One they all recognized. As one, the three Pillars kneeled on a knee and bowed to the new arrival.

A frail man with a disposition that calmed the soul. His cloudy eyes twinkled despite the smoke in his orbs, the purpling rot on his forehead spreading down to his chest and shoulders. He was not any older than the three. His kimono did nothing to hide his debilitation. By his side, a child calmly supported his father as he assuredly walked to the veranda.

"Thank you, Kagaya, for accompanying me."

His son simply nodded.

"Oyakata-sama." The Water Pillar greeted respectfully. "We were… you should be resting."

"Oh? I should rest as more of my children are taken away from me?" Their honored boss said with a serene smile. It made the words strike harder for them. "I know what you meant, Sakonji, but it would do no one courtesy now."

"I- of course."

Rengoku followed, "Lord Ubuyashiki. You honor us with your presence… I wish, it could have been under better pretense."

"I disagree, Shinjuro." The Ubuyashiki patriarch's voice and demeanor together made a well of tranquility. Even as his body deteriorated, even as his curse mark ate away his own senses, he revealed not even a hint of suffering. As was expected from the one who commanded the greatest of all respect from the Demon Slayers. "The past cannot change, but we can still look towards the future. As we are now, there is still much we can do. Our better pretense has yet to come."

"…You know what is to come." Kuwajima peeked at his boss.

The Ubuyashiki smiled at the sharpness.

"I know, Jigoro. And idling about will not let us reach it."

"Then what should we do?"

"I cannot tell what you should do. Only what has happened."

Ubuyashiki breathed slowly. Audibly.

"You know of the Breathing Styles that make up the core of our bulwark."

Flame. Stone. Thunder. Water. Wind. There was also Moon, but its style was lost to time, knowledge of it dispersing into the wind. And then there were the derivatives of the former five, each of them unique in their own rights. For the boss to bring this common knowledge (among Demon Slayers) up…

Something was wrong.

The grimness was tangible. The smile on their boss dimmed as he delivered the most shocking of news. The most terrifying.

"Amongst Kibutsuji's Twelve Moons, there is a Demon that knows an unknown Breathing Style."


A woman twitched. It was a familiar sensation, but she had long learned to embrace it.

Her apprentice, on the other hand, was hyperventilating, eyes jutting violently left and right as he tried to understand what was happening to him. To the uninitiated, it was as though he was suffering a panic attack. It was not far from the truth. Thankfully, she was there to calm him. To teach him that what he was feeling was a welcome feeling, as opposed to poison.

"Yushiro."

Her voice was enough. Like that, his panic ceased as he gradually returned to a familiar frown that seemed permanently embedded on his face.

"L-Lady Tamayo," Yushiro finally spoke as his voice returned. "What was that?"

"…" Tamayo did not know. More specifically, she could not say for certain. All she knew was that 300 years ago, she experienced this feeling twice. Both times, the one who turned her was mortally wounded. The first time had been that swordsman within that bamboo thicket who freed her from his control. The second time… she could not say, for she was not there to witness it, but she felt that that thing's agony like it was her own.

It was a sensation she truly relished. If it meant that the parasite suffered, she would take joy in it.

Her expression was solemn as she revealed what she knew to her apprentice.

For it to happen after so long…

"Yushiro."

Her voice resolute, Tamayo looked towards the west, outside the window of their current residence.

"It seems we have a new destination."

Her apprentice, ever so eager to please, stood up, fully recovered.

"Yes! I'll begin packing immediately!"


It was a phantom itch at first, but soon it turned into one of agonizing pain.

To think, the sensation would return after all this time. If the one before was seething, this was scalding.

Unlike all the times before, this time… it welcomed it.

"So… you are back."

"Do not think I was idle, Shura."

The figure turned its attention to the West.

"You had taught me what I lacked too well." The svelte voice was damning but at the same time, it was almost wistful. One could easily mistake it for respect. Perhaps it was. Perhaps it was not. "I thought I knew what it meant to wait. You had taught me otherwise."

"So I know now."

The man in Western clothes turned to the shore, eyes webbed and crimson. Before he disappeared under the moonlight,

"I am ready for what is to come."


A boat was arriving at the shores of Japan. Among the passengers was a variety. Some sought to earn their fortunes by coming to the Land of the Rising Sun. Some were eager to tour Japan. Some sought refuge, hoping for a better beginning.

Others… were simply returning home.

"We have arrived at the ferry! Welcome to Japan!"

And it was what finally brought two particular people back home after so long.

A particular pair made for a strange sight as they departed the boat. One was a man with a head nearly full of white hair tied into a long wolf-like tail, complete with clothes that made him appear more like a tramp than was acceptable to modern society. The most imposing thing about him was the large wooden case secured to his back that he carried with impunity, as if it did not bother, and how he hid his left arm from the world under a patchwork cloak.

The other was nearly the complete opposite.

"Divine Child."

"Sekiro." She nodded at him, nearly tripping over her footing. He righted her before she could begin falling, a hand gently holding against her womb. "…We're home. Kuro will soon be with us. Just… It's been so long, hasn't it?"

"…Yes."

The Divine Child had matured well. Once, she was but a child, jaded by the trauma of losing her friends to a cause she resented to the highest order. Now, she was older, touched by time at long last and showing a gentle wisdom that could not be seen by a naked eye. Now, she simply waited the moment for time to quietly take her to the great beyond.

He intended for that to happen. To live out the rest of his life alongside the Divine Child and Lord Kuro as they grow old and happy… that was the fate he had decided for himself. There were dreams to fulfill; small ones, but there was more than enough time to accomplish them.

She marveled at the sight before her.

"Isn't it wonderful? So long… yet, we're home again. So much has changed, yet I can still recognize it."

The shinobi kept quiet as he helped his liege off the boat.

"So many things we saw, so many things happening in the places we went through, and yet… we continued to venture. We continued living."

"You speak like this is the last time we speak, Divine Ch-"

"So much has passed, yet you still call me by that." She giggled, not at all offended by his obstinacy in referring her to her title. He turned to look at her. She smiled at him. "Won't you call me by that one?"

Wolf hesitated. It was not her real name, which was lost after what transpired on Mt. Kongou but still, it was a name she cherished. It was one he had said on a whim, one she took as her own afterward. To him, it did not mean much, but to her, the name held significant meaning. It was a name that freed her from the burdens of the past, to look forward to what was to come instead.

She was no longer just a Divine Child of Rejuvenation with that name.

"Mikoto."

As Mikoto, she was just a girl.


Fate has always been a cruel concept.

It is what wrought forth destruction.

It is what forces families apart.

It is what makes innocence be lost.

And yet…

Fate is equally as kind.

It is what causes meetings between people.

It is what forges unlikely relationships.

It is what tempers acts that can defy Destiny itself.


怨嗟の呼吸 PT 1


A/N: I went ahead and read the manga instead of wait for the movie to come out because I had nothing better to do. I found out the movie is coming out in October and I immediately thought, "I can't wait that long! I need it nooooow!" And since I did that, without spoiling anything like the KnY fandom is unusually fond of, I went ahead and began typing out the next chapters.

And then, the movie was postponed to next year. Nope, we're starting now.

Onto how the story is going to proceed. I initially placed some thought into chronicling Wolf's and the Divine Child's journey to the West and found that I'm severely lacking in things to write about, despite the materials before me. I'd legitimately thought about having them travel through all of China up until between the fall of the Ming dynasty and somewhere during the Qing dynasty, travelling further west towards Europe and the Middle East because China was apparently not the home of the Divine Dragon, bearing witness to the literal rise and fall of kingdoms and empires alike through the centuries – all the while fighting off Demons and the like – and having the journey conclude in Korea, and then returning back to Japan to live out their remaining (relatively mortal) lives, with some… additions, let's say, to their kit as a sort-of reward for returning the Dragon home.

But then, I realized that that has relatively nothing to do with Kimetsu no Yaiba and is essentially a Sekiro fic all on its own.

So against my better judgment, this arc begins with a timeskip. No need to mention that the actions of three centuries ago had severe consequences on the present. Perhaps I'll release snippets and tales of the two's journey as sidestories/omakes or something. God forbid, I have so many things to write about the two (three, counting Kuro) and their Journey to the West.

Oh, and this story has a TV Tropes page, like on the second day after this was first published. My fastest record yet. Let's see if I can do better next time.

-DarkAkatsuk1
P a treon. com (slash) DarkAkatsuk1