The first rays of winter sunlight filtered through the tall windows of the imperial estate, casting a warm glow across the polished wooden floors of the grand chamber. Servants scurried softly, carrying trays of food, water, and freshly folded linens. The air was a mixture of incense, wood polish, and the faint scent of tea. In the midst of this tranquil scene lay a small bundle of crimson — Hiroaki, the newborn with eyes like blood and hair like fire.
He blinked slowly, crimson irises flicking across the room with deliberate awareness. Most infants would be crying, flailing, or sleeping obliviously. Hiroaki? He was already observing, analyzing, and cataloging every detail of the room. The folds of silk on the bed, the trajectory of dust motes in the sunlight, the positions of the servants — all noted in the newborn's mind.
Well… not bad for a first day. Room layout acceptable and i am freaking loaded.
He flexed his tiny fists, feeling the subtle strength coursing through his arms and legs. It wasn't just reflex — even in this fragile body, there was control. Balance. Coordination. He could sense the slight difference in weight between the folded silk blankets and the floorboards.
A soft hum escaped his lips, more instinct than sound, and a nearby maid froze mid-step, sensing the intensity in those crimson eyes. She shook her head and muttered to herself, "Babies shouldn't be this alert…"
Lady Akemi entered quietly, gliding across the polished floor. Her crimson-lined kimono swished softly, her hair arranged in a way that emphasized both elegance and authority. She knelt beside her son, placing a delicate hand on his swaddled form.
"Hiroaki… you are awake so early," she murmured. Her voice carried warmth, but also a subtle curiosity. Her gaze lingered on the crimson eyes staring back at her.
Mother… interesting, Hiroaki's mind noted. Calm, elegant, sharp… predictive.
He let out a soft coo, flexing his tiny fingers once more. The servants whispered quietly among themselves, some glancing nervously, others simply intrigued. Hiroaki's attention, however, remained focused.
Humans are predictable. Fear is easy to measure. Curiosity even easier. Efficient interaction possible…
A tray of warm water and cloths was placed within his reach by another maid, who stepped back nervously. Hiroaki's crimson gaze followed the tray's path, calculating the trajectory, the slight wobble, the force required to tip it. With a subtle movement of his tiny hand, he nudged it — just enough to rock the tray slightly. Water sloshed harmlessly, yet the maid gasped.
Observation successful. Coordination developing. Reaction predictable. He let out a quiet, internal chuckle. Not bad… for a newborn.
Lady Akemi leaned closer, brushing a kiss across his forehead. "Grow strong, my son," she whispered. "And remember… the world may not yet understand you."
Hiroaki's tiny body remained calm, but his mind flickered with amusement. Interesting. They don't understand me yet. That is… useful.
A soft pop echoed inside his mind, sudden and authoritative.
[System Activated: Welcome, User Hiroaki.]
[World: Demon Slayer Era]
[Level: Beginner]
[Special Traits Detected: Inhuman Strength, Above-Average Intelligence, Crimson Attributes.]
Hiroaki's crimson eyes narrowed just slightly, a subtle smirk flickering at the corner of his lips. So… I'm really here. Reincarnated. Typical transmigrator scenario, huh? He hummed softly, a tiny sound that suggested amusement, curiosity, and the faintest spark of mischief.
Demon Slayer Era. Swordsmanship. Strength-based combat and a sick mentally ill want to be Michel Jackson. And, of course… all the fun possibilities.
Even in this fragile infant body, Hiroaki's mind was racing.
He flexed his tiny legs and rolled slightly in the swaddling cloth, enjoying the sensation of controlled movement. The servants glanced nervously at the minor disturbance, unaware that this infant was already assessing their reflexes, coordination, and even patience.
Observation complete. Environment manageable. Human interaction… moderately entertaining. Progressing well.
As the morning wore on, Hiroaki continued his subtle tests. He batted lightly at dangling threads, causing a minor commotion, and observed the maid's reactions. Some flushed with embarrassment, some laughed quietly, and some simply stepped back, unsure of what to make of the calm, red-eyed newborn.
Curiosity: piqued. Emotional responses: mapped. Future amusement: planned.
Lady Akemi watched quietly, a mixture of concern and fascination on her face. "He… is aware, isn't he?" she murmured to herself. Her hand rested lightly on his small shoulder. Even as a baby… he's not like other children.
Hiroaki cooed softly in response, though internally he considered the implications. Yes, Mother. Awareness is essential. Observation is survival. Understanding is power. And power… is very useful indeed.
Throughout the day, he explored small tests of coordination and strength — lifting a small plush toy with precision, turning slightly in his swaddling cloth without toppling over, and even measuring the reactions of those around him with his gaze alone.
Strength: above average. Reflexes: adequate. Emotional control: excellent. Observation skills: improving. Potential for mischief: high.
Occasionally, he let his thoughts drift toward the faint fragments of memories from his previous life — images of battles, people, and strange technologies he didn't belong to. They were hazy, disjointed, yet enough to give him a sense of advantage.
I remember… vaguely. Strategy, combat… situational awareness. Could be useful here. Definitely useful.
By evening, Hiroaki had already cataloged the behaviors of everyone in the chamber, measured his own strength and coordination multiple times, and tested his vocal range — the small hums and coos he produced were sufficient to elicit reactions, gauge emotional responses, and even subtly influence those around him.
Observation complete for the day. Initial strategy for growth: begin subtly, appear normal, gather information, and develop skills without alarm.
A final pop echoed softly in his mind, the system's voice almost playful.
[Hint: Observe. Adapt. Build Skills. Survival is Priority One. Fun is optional but encouraged.]
Hiroaki's crimson eyes gleamed faintly, the tiniest smirk forming on his lips. Fun… oh, there will be plenty of fun. But first… survival and growth. Then… everything else.
And so ended the first day of the Crimson Prodigy's life in this world — fully aware, calculating, and already plotting a path that would one day leave the Demon Slayer world trembling.
Even as the servants whispered nervously about the unusual calm of the red-eyed newborn, Hiroaki was already imagining the possibilities — a lifetime of training, mischief, strategy, and perhaps even… romance when the time came.
Step one: survive. Step two: grow. Step three: play. Step four… dominate. Sounds fair.
And with that, the crimson-haired infant closed his eyes for the first time in deliberate rest, his mind racing, planning, and preparing. The world had no idea who had just been born.