Ume, that's what Gyutaro calls his younger sister, though few know of this tender nickname between the infamous demons.
In truth, Daki's real name was: "Ume." It was taken from the illness that consumed their mother, a cruel irony that would follow them throughout their cursed existence. Just as she despised Gyutaro when he worked the streets, she harbored equal hatred for Daki. Fortunately, whenever the woman's rage turned violent, Daki found protection in her brother's fierce devotion.
Oboro saw the baby girl in her makeshift cradle during one of his early visits to the Rashomon Riverbank. Even as an infant, her perfect features were unmistakable, especially her striking eyes that seemed to hold depths far beyond her years. It was during a chance encounter by the Rashomon River that Oboro first witnessed Gyutaro, the prostitute, cradling his sister with protective tenderness.
But something had changed in the boy since then. There was an additional object in Gyutaro's grip: a sickle abandoned by a careless patron. This crude weapon represented more than a discarded toy; it symbolized the transformation occurring within the elder sibling.
Since Daki's birth, Gyutaro had shouldered responsibilities far beyond his years. He had become a brother, protector, and provider for Daki. His eyes, once filled with nothing but hunger and desperation, now carried a different kind of intensity. A dangerous potential lurked beneath the surface: aggressive and calculating.
He refused to let Daki suffer as he had. He refused to watch her scavenge for snakes, insects, and rotting scraps like a feral animal. She deserved better, and he would do anything to provide it for her, no matter the cost to himself or others.
Oboro's visit to the Rashomon River stemmed from a notable absence. For months, Gyutaro had stopped appearing at their usual meeting spots, no longer seeking the food or assistance that had once been a lifeline. As Oboro had predicted, once the boy had learned to survive on his own, he chose independence over charity.
The change was evident in more than just Gyutaro's absence. Passersby who had once looked upon the beggar boy with simple disgust and hatred now regarded him with fear. Their eyes darted away quickly, and they gave him a wider berth than before. Clearly, Gyutaro had undergone a significant transformation during these past months.
At the very least, he had learned to fight back against his tormentors, and he had learned quite effectively.
When Chiyoko approached with the prepared food, Gyutaro's response was telling. He didn't reach for the bundle as he might have in the past. Instead, he offered Oboro a respectful bow, deeper and more formal than before, and then turned and walked away without a word.
The gesture left Chiyoko frozen in place, uncertainty flickering across her features. She had expected gratitude, or perhaps even eager acceptance. This dignified refusal caught her completely off guard.
The pair returned home in contemplative silence, sensing that something fundamental had shifted in their relationship with the Rashomon siblings.
Spring melted into summer, and summer faded to autumn.
Oboro maintained his distance from the siblings' daily struggles, but news still found its way to him. Stories filtered through the district about Gyutaro's increasingly violent exploits. Despite his young age, the boy's fighting prowess rivaled that of grown men. Even more disturbing were the accounts of his ruthlessness, a cold calculation that left hardened criminals uneasy.
Gyutaro had effectively become the undisputed ruler of the Rashomon riverbank, a "little tyrant" whose reputation spread fear throughout the underworld.
Meanwhile, Daki had blossomed into breathtaking beauty. Her features, striking even in infancy, had developed into something almost ethereal. Men and women alike found themselves captivated by her presence, though few dared to approach her given her brother's fearsome protection.
As for their mother, she continued to work as a prostitute, selling her body to survive in the district's harsh economy. However, she had been effectively severed from her children's lives; they now lived completely separate existences. The rift formed when she attempted to beat Daki one time too many, finally pushing Gyutaro past his breaking point. The boy nearly killed her in his rage.
From that day forward, the woman lived in terror of her own son. She could only dare to speak ill of the siblings behind their backs, joining the district gossips who whispered about the "demon children" of Rashomon.
But Oboro's attention had shifted to more pressing matters: disturbing reports were filtering in from both the shogunate and the Demon Slayer Corps.
An interesting and troubling pattern had emerged over the past year: The demon population had begun to surge dramatically, suggesting that Muzan Kibutsuji had emerged from hiding and resumed active operations. However, unlike the chaotic demon outbreaks of decades past, these new demons possessed remarkable power and coordination. They were causing significant casualties among the Demon Slayer Corps' ranks.
Simultaneously, the demons under Oboro's influence, his inheritors, had begun systematically hunting Muzan's forces. Since demons can devour each other to absorb power and abilities, a direct conflict of interest was created between the two demonic factions.
Upon learning of these developments, Oboro immediately grasped the implications. After decades of careful study and experimentation, Muzan had achieved a significant breakthrough. He had learned to manipulate the will within the blood cells that Oboro had integrated into his inheritors.
Each inheritor carried traces of Oboro's essence: just a few drops of blood and spiritual energy designed to suppress Muzan's corrupting influence. More importantly, the will within those cells was meant to strengthen the inheritors' minds and spirits, granting them greater resilience and power.
However, because Oboro had used only minimal amounts of his essence, the will he could impart was relatively weak. For someone as cunning and powerful as Muzan, breaking through such defenses wasn't insurmountable. However, his ability to manipulate the will within blood cells meant that, after years of research, Muzan had discovered the energy of the soul itself.
Muzan was not only the progenitor of demons, but also a brilliant researcher. With his vast resources, extensive network, and centuries of accumulated knowledge, such a breakthrough was perhaps inevitable.
Of course, discovery doesn't equate to mastery. Oboro suspected that Muzan was primarily using physical transformations to influence deeper cellular structures, essentially achieving results through brute force rather than true understanding.
Previously, without Oboro's intervention, all demons existed within the same dimensional limitations. No matter how much they devoured each other or grew in power, they could never transcend their fundamental nature. However, with Oboro's blood essence integrated into the system, demons could consume each other and achieve genuine evolutionary advancement.
Oboro had effectively raised the ceiling of what demonic existence could achieve.
The four inheritors who fought in the Battle of Edo Castle, Yasuhara, Teshimaga, and the others, served as perfect examples of this enhanced potential.
Muzan recognized this opportunity, and clearly, someone among Oboro's inheritors had come to the same realization. Otherwise, the conflict between the two factions wouldn't have become so intense and brutal.
As for the Demon Slayer Corps, they had undergone their own dramatic evolution. The Ubuyashiki clan experienced two leadership changes, and the pillar-level swordsmen under their command were replaced multiple times. However, each new generation surpassed their predecessors in skill and technique.
Their mastery of breathing techniques reached levels that wouldn't have emerged naturally for another century. The current generation boasts more than ten active Pillars, two of whom have successfully manifested the Demon Slayer Marks. They had also discovered the power of the crimson blade and begun systematic instruction in its use.
These techniques and knowledge wouldn't appear for another hundred years in the original timeline. The acceleration of their development exceeded even Oboro's most optimistic projections.
Everything was proceeding exactly as planned, perhaps even more smoothly than anticipated.
Winter arrived with an unprecedented harshness that year.
A massive blizzard settled over the region, blanketing the Rashomon Riverbank's usual filth and decay in pristine white. Through the swirling snow, Oboro made his way alone to the riverbank, drawn by an impulse he couldn't quite name.
From a distance, he spotted the familiar figures of Gyutaro and Daki huddled together in a sheltered corner, sharing a threadbare straw mat for warmth. Despite the bitter cold and their obvious discomfort, the scene was beautiful, with Gyutaro holding his sister protectively and whispering promises and reassurances.
"We'll never be separated," Oboro heard him say, his voice carrying clearly in the still air. "As long as we're together, nothing can defeat us. Not poverty, not hunger, not the whole world."
Oboro remained at a distance, content to observe without interfering. The streets were empty due to the severe weather. Even through the obscuring snowfall, his dark silhouette was visible against the white landscape.
Daki was the first to notice him. She stared at the distant figure with curiosity rather than fear, sensing that this person was watching them specifically. "Someone's there," she murmured to her brother.
Gyutaro followed her gaze, his body tensing slightly. Though he couldn't make out the figure's features through the snow, he had a feeling he knew exactly who was standing there. The man made no move to approach or retreat; he simply stood and watched.
"Maybe he's lost," Gyutaro suggested to his sister with a gentle smile, though his voice carried a note of uncertainty.
Daki, who had never met Oboro directly, readily accepted this explanation.
After what felt like an eternity, the figure finally turned and walked away. His footprints quickly filled with fresh snow.
Only then did Gyutaro allow himself to relax. He hadn't been afraid, exactly; fear wasn't the right word for how he felt about Oboro. It was more complicated than that. Gratitude, certainly. Respect, without question. But he also felt an overwhelming sense of indebtedness that he couldn't possibly repay in his current circumstances.
He didn't want Oboro to see them reduced to shivering in the snow like abandoned animals. It wasn't out of pride or dignity; those were luxuries he couldn't afford. Rather, he felt the weight of Oboro's past kindness so keenly that witnessing their current misery would feel like a betrayal of that generosity.
On his walk home, Oboro studied his footprints in the fresh snow, his thoughts turning inward.
The people of this world were fundamentally different from those he had known in his previous existence. Their emotional development followed simpler, more direct paths, making their feelings incredibly pure and focused, whether toward good or evil.
There was something almost refreshing about such straightforward humanity, even when it manifested in darkness.
"You've learned quite a bit, sir," he murmured to himself, a soft smile playing at his lips.
With his enhanced perception, he could see the small tree that symbolized the will of this world. Its branches, which had previously been withered, had regained vitality and were now dotted with vibrant green leaves. Even the trunk had grown noticeably thicker and stronger.
The tree swayed gently in an unseen breeze, its leaves rustling as if in response to his words, whispering an acknowledgment of the changes taking place in this world. These changes were set in motion by him, but they were now developing their own momentum.
The bonds between Gyutaro and Daki, the escalating conflict between demon factions, and the rapid advancement of the Demon Slayer Corps were all converging toward something significant: Something that would reshape this world's destiny entirely.
In the quiet space between snowflakes, Oboro found himself genuinely curious about what form that destiny would ultimately take.