Past midnight
Ubuyashiki Mansion
The pillow at the head of the futon was already half-soaked and completely drenched with milk. A very enchanting, sweet scent rose from it and slowly spread through the entire room.
Inside the futon, Tanjiro's face rested quietly against Kie's breasts, his nose nestled comfortably between her soft, attractive valley.
Every breath he took was thick with her rich, intoxicating scent, further deepening the imprint that had already been carved into his mind.
His arms and legs were tightly wrapped around Kie's voluptuous body, refusing to let go of her warmth even for a moment.
She was humming the same lullaby while gently ruffling his hair with deep, overflowing affection.
Tanjiro, eyes half-closed, listened quietly to her voice and savored every second of the treatment.
For hours he had devoured her milk like a true devotee, caring about nothing else in the world.
Even after the system notification appeared, his mouth never stopped. He continued gulping down his mother's milk with pure fervor. His belly had been full for a long time, yet he didn't care in the slightest. The softness of her breasts and the erotic sensation of her nipples were enough to keep a powerful flame roaring inside his mind and body, his desire burning without end.
At this point, he knew the truth.
He was addicted.
There was no going back now.
Deep down he wished these moments could remain eternal and unchanging, but his remaining sanity told him it was only his brain rebelling against the idea of Kie returning to normal. His mind was fighting the thought of everything going back to how it used to be.
'Uhhh…' He groaned inwardly.
He had no choice. He absolutely had to cure Kie as soon as possible.
To do that, he needed to find the demon woman named Tamayo and ask for her help.
But he wasn't completely sure of her current location.
'Fuck… Think! Focus!'
He closed his eyes and rummaged through the memories from his life on Earth.
Thanks to his superior concentration, it took only a minute to find the clue.
'Asakusa, Tokyo… but there's a good chance she isn't there yet. If that's the case, I'll just make Shinobu handle the research. She doesn't have centuries of experience like Tamayo, but she's extremely capable… Hm, she won't refuse, right?'
Having settled on his next steps, Tanjiro mentally tapped the [Claim] button without even opening his eyes. His senses were so sharp he could "see" everything around him perfectly even in total darkness.
Almost instantly, overwhelming drowsiness crashed over him. A few seconds later, the system forced him into deep sleep.
Kie felt her child go limp and instinctively pulled the blanket tighter around him.
Noticing the pillow was soaked, she tossed it aside, gently rolled him on top of her, and let him sleep against her body while continuing to caress his back with motherly love.
The only memories left in her mind were of Tanjiro's birth. Those feelings were absolute. She would do anything, go to any length, for her little child.
Even the insatiable hunger for human flesh couldn't overpower that single command he had given her: do not hurt humans.
So she endured, no matter how ravenous she became.
While Tanjiro slept peacefully on her chest, Kie simply stared at the ceiling.
A few minutes later, something strange caught her attention.
She looked down at Tanjiro with faint surprise.
Was her baby… growing?
As a demon, her senses operated on an entirely different level.
Nothing in direct contact with her body could escape her notice, even passively.
So how could she miss the fact that Tanjiro's body, pressed against hers, was rapidly changing?
Right now, his body was developing at an impossible, accelerated pace.
Kie watched quietly. Once she confirmed it was harmless, she calmed again, though she never lowered her guard, still checking for any abnormalities.
Time continued to pass, and before long, morning arrived.
Dawn had just begun.
Tanjiro's eyelids fluttered as consciousness slowly returned.
The first sensation that hit him was an overwhelming warmth and the soft, cushion-like body enveloping him completely.
'Hmmm?'
In a split second, he understood everything.
Kie was still glued to him, arms wrapped tightly in an embrace.
"Mother… it's already morning," he murmured in a low voice.
Kie, sensing he was awake, gave a gentle nod.
She began lifting his body along with hers.
"It's fine… I'm up." He rubbed his face against her chest one last time before pulling away. Kie sat back in seiza and stared at him intently.
She spoke softly, "Tanjiro… you grew up."
"I did?" He looked genuinely confused.
Only when he stood straight did the change finally register.
The ceiling was closer.
His vitality had surged.
Even Kie's figure looked… smaller?
'Wait… the system! Explosive Growth…' It clicked instantly.
He had been forced into sleep last night. He remembered now.
'Growth… my body actually developed overnight?'
The difference was impossible to miss.
Yesterday he had barely been 150 cm. Now he was easily 170 cm or taller!
'Holy crap… this bitch-ass system…! How am I supposed to explain this to everyone?'
He cursed inwardly, but that was it.
Cursing wouldn't undo anything. He had claimed the reward himself, so now he had to deal with the consequences. Not that he really minded. It wasn't a big deal. It was just his height that had… wait.
'Huh…?'
He felt something on his shoulder. Hair?
'…'
Not just height and hair. His entire body had gone through explosive growth in a single night.
Standing in shock, Tanjiro stretched the waistband of his pants forward and raised his eyebrows.
'Oh you godly system… how should I thank you!'
His eyes actually teared up a little.
His once modest buddy was finally free of its curse. Now it was bigger, manlier, domineering. Easily 16 cm or more…!
Nearby, Kie tilted her head curiously. Seeing her child so emotional yet overjoyed sparked her interest, though she stayed quiet.
A faint ray of sunlight slipped through the window. Kie instinctively retreated into the basket and closed the lid herself.
Tanjiro made sure it was secure, then casually gathered his much-longer hair and tied it into a small bun at the back of his head. He'd deal with it properly later.
His old clothes were comically small now; even his muscles looked more refined and defined.
Releasing a long sigh, he decided to take a bath and find something that actually fit.
Half an hour later.
Thanks to the electric heating rod in the mansion, the bath was quick. He preferred warm water in winter anyway, and he had already planned to visit the hot springs with Nezuko and the others in the future.
Finished, he changed into properly sized blue clothes that had been prepared and returned to his room.
He lifted the basket onto his back.
"Mother… let's go visit Nezuko and the others."
"Mm…" Kie's soft voice came from inside.
Using his sharpened senses, he located the life signatures in the estate. Most were already awake; only Mitsuri and the quintuplets were still sleeping.
'Heh, heavy sleeper? I'll let her rest for now, haha… I'll be back shortly anyway. Let's hurry.'
Without anyone noticing, Tanjiro slipped out of the mansion. He caught Nezuko's scent from a distance and dashed toward the Butterfly Mansion at full speed.
He missed his little sister deeply, and he was a little worried about the others too.
'I'll ask Kagaya for a Nichirin sword once he's back… No one must see the Heavenly Demon Sword except for Nezuko and my close family. It's far too precious and shocking…'
....
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