Zenin Toji was dying.
To be precise, his heart was dying in tandem with his wife, who lay on the verge of death.
It had been months since she had collapsed into that hospital bed.
She had become terribly gaunt, a mere shadow of her former self.
She was barely clinging to life, tethered to the world by IV drips and the rhythmic hum of machines.
But now, even that shallow breath was preparing to vanish.
His wife's death would be his own.
It signaled the extinction of the humanity that had only just begun to sprout within the man known as Fushiguro Toji.
"…"
He remained silent, his hand gripping hers.
There was no emotion in the gaze he fixed upon his wife.
Outwardly, he appeared stoic, indifferent. But inside, he was rotting away.
That was his reality.
An incurable disease of unknown origin.
Complications from an accident.
Or perhaps something else entirely.
The fragments of explanations he had heard from the doctors flickered through Toji's mind.
Briefly, like the cold light of distant stars.
"Sshh…"
A heavy sigh leaked from his lips.
It was a breath thick with regret and suffocation—a complex exhale that felt like he was casting away his very soul.
Whoosh.
As if waiting for that very moment, a gust of wind blew into the room.
It was a sunny spring day.
Much like the day of their first date.
However.
While that first date had been fresh and heart-fluttering, it had lacked this bone-chilling coldness.
And it certainly hadn't featured an uninvited guest.
"Who's there?"
Toji lifted his head.
Outside the window he had left cracked for his wife, someone was standing on the railing.
A child.
A boy, perhaps five or six years old.
He wore a simple shirt, shorts, and sneakers.
His attire was mundane, but his features were strikingly refined.
More than anything, the atmosphere he radiated was unique.
His presence was intense, yet it felt as if the moment you looked away, you would forget him entirely.
Conclusion: The child before him was no ordinary child.
He was the same breed as those pathetic fools crawling around the Zenin estate.
He was like those selfish curse users whose throats Toji had personally slit.
"Fushiguro… No, Zenin Toji-san. Is that correct?"
The boy asked politely, perching on the railing.
His tone was too refined.
And his composure was far too adult for his age.
Unnecessarily so.
"You know me?"
Toji narrowed his eyes, his voice low.
Knowing him meant the boy belonged to the other side—the world of jujutsu.
It meant there was a high probability of some old grudge or hidden agenda.
"I do. The Sorcerer Killer, a man who slaughters jujutsu sorcerers with ease."
The boy nodded.
He had come seeking him out specifically, so ignorance was impossible.
He knew Toji's profile, his traits.
And perhaps even the future that was originally meant to unfold.
"Then your timing is impeccable. Are you here to kill me? Or to hire me? Which is it?"
"I am here to strike a deal."
The boy blinked as he looked at Toji.
Even as Toji began to radiate a faint killing intent, the child remained tranquil.
The distance between them was negligible—less than a second's worth of movement.
In the blink of an eye, Toji could have reached out and snapped his neck.
The boy was well within Toji's strike zone, yet he showed no fear.
He wasn't here to fight.
Furthermore, even if it did come to blows, he was confident.
His mature, seductive, gentle yet dangerous sisters would surely protect him.
"A deal?"
"Yes. Become my slave, and I will save your wife."
What?
In an instant, Toji's eyes widened in shock.
Save her? His wife?
How?
The ambush Toji hadn't expected hit him harder than any physical blow.
It was as if someone had taken a sledgehammer to his brain.
As a result, his reaction was delayed.
"…I'll only let you use my wife as leverage once. I don't care if you're a brat, I won't go easy on you."
A faint, murderous light flickered in Toji's eyes.
It was difficult to forgive a child who seemed to be mocking his desperation.
If it were a curse—
If some trivial reason like a curse was the cause, he would have dealt with it long ago.
But this was an incurable illness.
In other words, it was science that had yet to find a solution.
He had searched for anyone with a technique that could cure disease, but found none.
Wielder of the Reverse Cursed Technique that heals physical damage?
Such techniques cannot cure illness, and even if they could, no such master of that scale existed.
"This is not a joke, nor is it a taunt or a deception. I have brought a definitive solution."
The boy reached into his pocket and pulled out a small glass vial.
It was about the size of an adult male's index finger.
"That… that's the solution?"
Toji stared intently at the vial.
Inside, a shimmering pink liquid sloshed about, looking almost ethereal.
"Yes. You simply need to form a pact… rather, a Binding Vow with me. And sign a contract as well."
A Binding Vow was exactly what it sounded like: a restriction.
An oath to accept certain conditions and suffer the consequences of breaking them.
Such vows were particularly potent when made between jujutsu practitioners.
In many ways, they were more reliable than any legal contract.
And despite Toji's inability to use cursed energy, he was no exception.
He, too, was a being that existed within the world of jujutsu.
"Are you serious?"
Toji asked.
The prospect of becoming a slave didn't scare him.
What mattered was his wife.
Only his wife.
His pupils trembled slightly.
The rain had finally begun to fall on his parched, cracking soul.
"I am."
"And since you want to make me your slave, I assume you're after my strength?"
"Correct."
The boy nodded and held out the vial, prompting Toji to take it and administer it to her.
"The moment you take this, I will consider it an acceptance of our contract—the Binding Vow."
"No lies, right?"
"If this medicine fails to cure your wife, the contract is void. Furthermore, even if you accept, I will never issue an order that would harm her."
The boy paused briefly before delivering the most critical assurance.
"Additionally, I will stake my life via a Binding Vow that this medicine is harmless."
That was enough.
Toji had worried the boy might command him to kill her with his own hands after the recovery… but with it codified in a Binding Vow, it would be fine.
More than anything, Toji was currently clinging to a strand of hope.
When one clings to hope, there is no looking back.
Rational judgment?
That was out of the question.
He didn't have the luxury of checking if the rope thrown to him was rotten or not.
He just had to grab it.
That was all that mattered.
"If my wife is completely cured, I will gladly accept your Binding Vow."
"Excellent. Tomorrow at this time…"
The boy began to suggest a meeting but trailed off.
Coming all the way back here was a bit of a hassle.
"Let's meet tomorrow night at ten, at the convenience store near the hospital. She'll likely be discharged tomorrow, so that should be plenty of time, shouldn't it?"
"Yeah."
Toji nodded and stepped toward the boy.
He reached out and grasped the vial.
"This is it…"
Toji stared at the bottle, muttering to himself.
He was still suspicious, yet stunned by the sudden turn of events.
"Well then, I shall see you tomorrow."
The boy slowly turned his back.
They were on the fifth floor.
Despite being quite high up, he looked ready to leap.
'As expected.'
Toji looked up and observed the boy.
Jumping from here would be a suicide mission for most.
An ordinary person would be severely injured or die.
But a sorcerer could protect their body with cursed energy.
The more skilled the sorcerer, the less impact they would feel from the fall.
But why go to such lengths?
"Is there a reason to jump out the window? You could just walk out the door."
"It looks cooler. And it's faster."
The boy glanced over his shoulder with a grin before hopping off.
There was zero hesitation.
'Is he insane?'
Toji leaned out the window, his eyes wide.
His heightened physical instincts reacted reflexively.
Fortunately, the boy was fine.
No broken limbs, no blood.
However.
Standing beside the boy was a woman he hadn't noticed before.
— Honestly, Master! You shouldn't just jump without a signal! If I hadn't noticed, you could have been seriously hurt.
— I always had faith in you.
— Hmph! Are you trying to brush it off again?
— I didn't know our Yaskaya was such a nagger.
Toji stared intently at the distant woman.
Despite the distance, his vision was as sharp as if she were standing right in front of him.
'A white suit and a short skirt. Is she an office worker? Or a sorcerer—perhaps a curse user—posing as one?'
She had a sweet voice that could melt the heart of any man or woman.
A perfect physique—curvaceous hips and chest with a cinched waist.
And a beautiful face to match.
In a word, she was a peerless beauty.
'She's looking this way…?'
The woman, who had been attending to the boy, turned her head.
Around, and then upward.
As she moved, her pale pink hair swirled around her like a veil before settling.
The moment it cleared, she locked eyes with Toji.
"…!"
Suddenly, Toji's eyes went wide.
Her pupils shone with an uncanny, malevolent light.
Beneath the surface lay a hidden sharpness and an unfathomable depth that sent a shiver down his spine.
That thing was not human.
A cursed spirit. At the very least, a Special Grade.
Just as he instinctively stepped back and entered a combat stance.
An alluring smile played on the woman's lips.
It was intoxicating.
For a fleeting second, it felt as though he had been submerged in the crushing pressure of the deep sea.
— See you tomorrow.
The woman mouthed the words while looking at Toji.
Then, she turned and walked away.
"Phew…"
Toji only breathed again once the woman and the boy had vanished from sight.
It had been a terrifying moment.
'I won't be forgetting that for the rest of my life.'
For the first time in a long time, Toji felt his back soaked with cold sweat.
It was a very memorable first encounter.