Her head tipped back, eyes narrowing at his.
A second later they flew wide, her mouth falling into a small circle, words tripping over themselves.
"B-big brother, why do you smell like a Gastrea?"
Shock had scrambled her phrasing.
It wasn't a Gastrea smell hanging on him.
It matched hers exactly. The scent of a Cursed Child, the mark of the Gastrea Virus living inside a body.
Which made even less sense.
Turning it over in silence, her surprise curdled into confusion and unease.
Cursed Children were always girls. Not once had a boy ever become one.
And their lives ran short. With Corrosion Rates climbing without pause, most never reached adulthood, let alone anything close to his age.
Beyond that, he'd been a normal human until minutes ago. Nobody crossed that line in the space of an afternoon.
The older girls had taught her the only path years back: infection had to happen in the womb, while the body was still forming.
Any other route, any human already born and injected with a Gastrea's fluids, ended one way.
Total corrosion. A mindless monster. Never a Cursed Child.
Color drained out of her face, guilt flooding in behind it.
Her head dropped. Fingers twisted into the hem of her shirt, and her shoulders trembled.
Did I do this to him?
Did the virus in me pass to him? It's my fault. If I hadn't followed him, he'd never have turned into a Cursed Child, he wouldn't be burning up like this...
The thoughts circled and circled. Her eyes reddened, tears gathering and threatening to spill.
She looked up at that flushed face, at those strange eyes, and the guilt pressed harder until her voice cracked.
"Big brother, I'm... I'm sorry..."
The apology, and the face on the edge of crumpling, told him everything.
She hadn't said any of it aloud.
But nothing stayed hidden from the Six Eyes, least of all the workings of a child's heart.
He read the guilt sitting there plainly, and something in him softened.
"This has nothing to do with you, Aii. Don't carry that around."
He bent slightly and rested a hand on her head, palm warm, his smile gentle enough to melt stone.
Under his touch the tears finally broke loose, sliding down her cheeks and dotting her collar with small dark spots.
She sniffed and lifted a tear-streaked face toward that smile. The guilt eased a fraction, though the crying didn't stop.
"Big brother, is it... is it really not because of me?"
She still couldn't believe it. Some part of her insisted the virus in her body had reached the person she loved most.
"Of course not."
He brushed the tears away, fingertips moving as carefully as if she might break.
"This was my own choice. It has nothing to do with you at all, understand?"
Betty surfaced from her shock then, eyes flying open, her voice unsteady with disbelief.
"You're infected with the Gastrea Virus?!"
She hadn't kept her voice down. Alarm carried it across the whole clearing.
The children at play, Sumire Muroto sorting through the examination records, Elder Matsuzaki standing off to one side. Everyone heard.
Laughter cut out. Every smile vanished, replaced by fear and something heavier.
They were all Cursed Children. All of them had been loathed and driven off since birth for what lived in their blood, and all of them had watched friends whose Corrosion Rates climbed too high turn into the monsters they feared. In their world, infection meant the countdown had started, and death waited at the end of it.
But this was the big brother who'd brought them warmth, who'd fed them, who stood between them and everything else. The strongest and steadiest person any of them knew.
They were afraid. Afraid the gentle one would become one of those horrors. Afraid of never seeing him again.
Still, apart from the flush and the odd look in his eyes, he seemed fine. So they gathered their courage and crept closer.
A few with some fighting ability drifted to the front without thinking, small bodies straight as soldiers, shielding the younger ones behind them.
Determination sat on their faces. Their eyes gave away the nerves underneath.
"Big brother, are you okay?"
One of the braver girls tilted her chin up, voice thin and catching.
"Someone as good as big brother couldn't get infected..."
A boy stared at the ground, fingers knotted in his shirt, his voice barely audible and thick with hurt.
"But... but big brother really does smell like a Gastrea. Just like us."
A girl with pigtails offered it quietly, worry and doubt tangled together.
Every voice stayed low. Every sentence carried the same fear. Wide eyes fixed on him, waiting.
He looked around at the ring of small anxious faces, and something warm moved through his chest. His smile softened further.
"Infected?"
A shake of the head, easy and unhurried, and he looked from Betty to the children pressing in around him.
"No, no, no. You've got it backwards."
"This isn't the kind of infection you're thinking of."
He turned slightly and dropped his voice, leaning toward Betty with a conspiratorial edge.
"I only went and acquired the power."
Infection she could have followed. Plenty of people in this world got infected.
Acquired the power short-circuited her entirely. Her mind went blank.
Small brows knitting, she stared at him and worked to make the sentence mean something.
She didn't stall long.
Her eyes widened as it clicked, and she asked carefully, testing it.
"Like... like the Ten Shadows Technique before?"
She remembered how that had appeared, out of nowhere, by no method anyone could explain.
By every rule of Jujutsu in his world, a hereditary technique should have been impossible for an outsider to obtain.
He'd done it anyway.
"Got it in one."
He snapped his fingers, the sound sharp and pleased with itself. "Exactly that."
"And you don't need to worry."
Catching the concern still sitting in her eyes, his tone turned serious.
"Corrosion Rate doesn't apply to me. It flat out doesn't exist as a concept where I'm standing."
"I'm not turning into a Gastrea either. This enhancement has no side effects. It's power and nothing else."
The weight lifted off her chest. Worry gave way to exasperation, and she shot him a withering look, scolding riding under the complaint.
"Next time something like this happens, could you mention it in advance?"
"Don't just spring it on people. You scared me half to death, do you understand?"
She had been terrified. The thought of him becoming a Gastrea, of him leaving, had opened a hollow feeling she'd never felt before.
"Sorry, sorry."
He pressed his palms together in apology, wearing a placating grin. "I worried you. Next time I'll warn you first, no more scares, promise."
"Who would ever worry about someone like you? Hmph."
She turned her head away, refusing to look at that grin, though the corner of her mouth curved and gave her away.
She claimed indifference. Nobody cared more about the reckless idiot than she did.
Aii stayed worried beside them. Acquiring power meant nothing to her. She only knew his body might be in trouble.
Tugging at his sleeve, she lifted her wet face and asked in a small voice.
"Big brother, are you really all right?"
She'd spent her whole short life paying for what lived in her blood. Hated by humans, pushed out by her own kind, scraping by in dark sewers, watching her Corrosion Rate and dreading the day she became the thing she feared most. Now the person she admired above anyone carried the same scent, marked by the same virus, and it hurt in a way she couldn't name.
"Relax, Aii. There's nothing to worry about."
His hand found her head again, voice gentle and certain, his smile the kind that settled nerves. "I'm fine. Nothing's wrong with me at all."
"In a while, I'll have Sumire take a proper look at this power."
He paused, anticipation flickering through his eyes. "Maybe then we can make you and all the others the same as me."
"No more Corrosion Rate hanging over you. No turning into Gastrea. You'd live like ordinary children and grow up properly."
Her eyes lit up. Tears still shone on her cheeks, but a bright smile broke through them.
"Really? Big brother?"
"We could really become like you? We'd never have to worry about turning into Gastrea again?"
Her voice shook with it. This was the thing she'd wanted for as long as she could remember, and it sounded too large to believe.
"Really."
He nodded firmly. "I keep my word. I'll get the Gastrea Virus off your backs and give all of you the life normal kids get."
Betty watched him say it and held her gaze on him a long moment, saying nothing, something complicated moving behind her eyes.
He never made promises lightly. Once made, he kept them.
She also knew exactly how impossible this one was.
The corrosion of the Gastrea Virus had defeated every scientist alive. Even Sumire Muroto had only managed a Suppressant, slowing the climb without ever erasing it, let alone reversing it.
Yet looking at the certainty in his face, she believed him anyway. Miracles followed him around.
After a silence she couldn't hold, she asked.
"You want Sumire to study you so she can find a cure for the Cursed Children?"
"Mm-hm."
He nodded, tone light but underlaid with steel. "Humanity in this world has nothing effective against the Gastrea. Nothing at all."
"The Suppressant buys time. It doesn't fix anything at the root."
"So I've been chewing on one question. How do I actually help these kids?"
His gaze traveled across the children ringed around him, warm and unwavering. "Most of the world hates the Cursed Children. That's the reality."
"It's not like dealing with the Higher-ups. Those people did evil, so I removed them."