Once he finished his training duties, Tanjiro let the tired girls do whatever they wanted: chatting, washing up, or resting. He especially told them not to do any heavy workouts for a while, as it would disrupt his methods. In the end, they simply stuck to practicing Total Concentration Breathing: Constant diligently. Seeing that, he gave them a satisfied thumbs-up before heading back to his room.
'Mitsuri will leave the Butterfly Mansion the day after tomorrow to visit her home. This time is an exception, after that she'd only have two days of holiday with every ten days of practice, huh. Since it won't disrupt her training schedule much and gives her body enough rest, it's fine, I guess.' He pondered while jumping onto the roof to reach his room's window.
Mitsuri's parents had been told, or rather lied to, that she was working as a maid for a middle-class noble family. Knowing Mitsuri's stubbornness from childhood and the high weekly pay, her parents didn't question it much. As long as their daughter was safe and happy, they let her make her own choices. And since she could visit every ten days, they felt reassured about her safety. From their perspective, she wasn't in any danger given her gifted body and superior strength.
'Flower Breathing, huh. Although it's good for females with shorter, less muscular physiques than males, the techniques themselves are very elementary. There aren't many forms either, only six sword forms and an ocular technique that increases focus, though it damages the eyes in the process. I should add four more sword forms to it. That will give the other two a better edge against demons.'
He had picked up a faint trace of jealousy from Kanao earlier, though it was low. He wanted to give her something too. It would boost her confidence and deepen her trust in him even further.
With his absurd talent, creating a new Breathing Style or adding forms to an existing one was child's play. Dismantling techniques, understanding the sword's intent, figuring out footwork, calculating force, eliminating openings — none of it meant anything to his eyes. He could even simulate how the style would perform against powerful demons in his mind. After all, these techniques were simply derived from his own Sun Breathing.
'Kanao's a few months older than me, huh.' He thought. 'Hm, I should learn their birth dates later. It'd be nice to celebrate together. I'm being paid a lot anyway, and money is the least of my concerns. Hmm, what's this...'
Although he could sense people's life signatures and pick up their scents with ease, pinpointing exact locations of so many people in the same house was still a bit difficult. Because of his heightened focus, Transparent World activated on its own like a reflex. His vision pierced through the house structure like an x-ray and landed on a petite figure wriggling like a snake on his bed.
'What the… Nezuko?' His eyes narrowed in disbelief. 'Is she… sniffing the scent? Oh damn…'
She was the only one on the second floor; the others were busy playing on the ground floor.
Cutting off his presence entirely with Selfless State, Tanjiro appeared near the window quietly, catching his innocent sister in her very first purely primal act.
She didn't mind the wooden container in the corner where Kie, her mother, rested. Instead, she continued sniffing the pillow she had pressed tightly to her face. Meanwhile, her body twisted and turned on the bed, legs kicking up and down in excitement.
A powerful scent of arousal radiated from her whole body, impossible for Tanjiro to miss.
Seeing her like this, he sighed inwardly.
'She turned twelve recently. That explains this situation, somewhat. Ah, her hormones must be going crazy.' He nodded to himself.
Not looking anymore, he sat down outside the window, leaning against the wooden frame. He opened the already-finished book and began reviewing important topics in deep concentration, ignoring the soft shuffling and rustling coming from inside.
A cold breeze blew, lifting a few strands of hair from his forehead. His gaze remained fixed on the pages.
Five minutes passed, he realized.
Then, suddenly, a low mumble reached his ears — all thanks to his absurdly powerful senses. All five of his senses were monstrous, though smell still stood out the most.
"Onii-chan… why are you keeping Nezuko away~ Do you not love Nezuko anymore…"
'…'
His inhumane heart, which still beat normally, suddenly felt like it was being gripped.
Had he not focused on Nezuko enough?
No, it wasn't that. He had given her equal time as the others — playing with her, eating with her, reading with her, hanging out before putting her to sleep. Was he still lacking?
But as sharp-minded as he was, he figured out what had gone wrong.
What Nezuko needed wasn't just his presence. She wanted his love — her Onii-chan's taboo love — all to herself.
'Fuck these circumstances…' he cursed inwardly.
Next, out of nowhere, that familiar mechanical sound rang in his mind.
[Ding!] ×2
[𖤐 Mission: Satisfy Nezuko]
[𖤐 Reward: Birth Control]
[𖤐 Mission: Have Sex with Nezuko]
[𖤐 Reward: Heavenly Charm]
'…'
An expressionless look settled on Tanjiro's face.
But the next second, his hand reached for his face as he leaned back and looked at the azure sky through the gap between his fingers. 'I'll play along… for now.'
Putting his book aside, he jumped inside the room sneakily. No sound was made whatsoever.
His crimson gaze immediately landed on his petite sister lying on the bed on her stomach lazily, toes stretched to the maximum.
Deep sniffing sounds came from the pillow she had stuffed her face into and clung to desperately.
'She's such a cutie pie…' He smiled.
Perceiving that nobody was on the second floor except Kie, of course, he kept his perception active and crouched down on the floor. His head rested on the corner of the bed, arms folded beneath it, watching her with an obvious smile.
'Like mother, like daughter, huh… I'm no different, though.' He laughed softly in his mind.
Observing her closely — how her back arched after a deep inhale, the playful movements of her legs like Kie's, the twitching of her earlobes, the faint blush near her nape, how she rubbed her crotch against the mattress, how she raised her small butt after exhaling from her mouth — he unconsciously swallowed the saliva forming in his mouth.
Even though his body had matured to that of a 17- or 18-year-old, nothing like the one he had a week ago, his sexual desires had also surged tremendously.
Though he had kept his lustful urges in check and subdued them, seeing his sister enjoy herself so innocently while sniffing his scent was turning him on so much that he didn't realize how hard his dick had become inside his pants. Pre-cum was already leaking, he felt.
'When did she start doing this…' He couldn't help but wonder.
Was it even before their father's death?
Did she become like this the day he kissed her?
Yesterday when he was absent?
Or was today her starting day?
"Nezuko…" A quiet murmur left his mouth.
The girl, eyes closed, was recalling the moment from the past — the time her Onii-chan had kissed her so passionately for the first time. The way his tongue moved inside her mouth. How lovingly he touched her cheeks and expressed his deep care.
"Onii-chan~ Nezuko wants you…" she purred like a maiden begging for her husband's affection, swaying her hips instinctively.
She didn't know what this feeling was.
Between her legs… it was hot. Too hot.
The only thing she wanted was a kiss, but for some reason there was a lot of tingling near her crotch.
Her heart beat so loudly she could hear the pulse in her ears.
"Onii-chan~" Bringing her thighs close, she started rubbing them together naturally, not realizing it at all.
"Nezuko…" A soft, gentle voice reached her once again.
Her mind felt light-headed. It was so fuzzy that she thought she was hearing her Onii-chan calling her name.
A few seconds passed as she kept hearing his voice, thinking it was all in her head.
Only when she shifted sideways for a moment did her half-opened pink eyes catch sight of someone's head resting on the bed. A faint, familiar smile was on the face.
'…'
For a moment, her mind overloaded.
Her mouth twitched wildly, pupils flickering rapidly.
An expression of shame and horror overtook her earlier lust-filled one.
With brows raised in alert, her throat trembled as a sharp voice came out. "O-Oni—!"
~~<>~~
To be continued~