Chapter 9: It Runs in the Family

"Nii-san? Is that you?" The girl called out, pulling away from the wall, eyes narrowed to get a better look at Chuuya's face. Chuuya couldn't reply, mind still reeling from shock. He had a sister?

The girl's face hardened as she saw the confused look on his face. "You," she began, the chains restraining further movement, "You look like my brother. But," blue eyes scoured his face warily. "Who are you, really?"

Chuuya narrowed his eyes. "Why should I answer that?" He hesitated, then tacked on with, "I don't know whether I have a sister or not. I don't know who you are."

The girl stared at him for a while, then relented. "My name is Nakahara Chizue. What's yours? And where are you from?"

He sucked in a breath. "Nakahara Chuuya. I'm from Yokohama, Japan." Chuuya could see the girl's pupils dilate – she knew his first name. That didn't mean much, though. Plenty of people knew his first name, ever since he'd decided to ignore the Japanese ways of greeting in favour of being direct. He focused back on the girl as she started to mutter to herself.

"Looks like him – same name – no memory – but maybe – the incident? No – maybe it's a trap – like the others? But – sounds like him – could he – Wait." She focused on him again. "What's the number on your neck?" She demanded.

"Wha – How do you know about that?" Chuuya snarled back, his mind racing. No one knew about that number tattooed on his neck, a memento of the days he'd had no memory of, a remnant of the time before he and Arahabaki merged. Not even Kouyou-nee knew the exact numbers that were imprinted there, only about its existence. (There was also Dazai, but that shithead didn't count, not when he'd liedbetrayedhurtabandoned) Chizue huffed.

"All experiments from here have them. And it's the only way I can think of that will prove that you're telling the truth." Chuuya scoffed at that. "What makes you think I believe every word that you say?"

Both parties eyed each other warily. Eventually, the girl sighed and uncrossed her arms.

"I've got a number as well. Look, we can be here debating over whether who's telling the truth or not, but I think the only way we'll ever know is by showing each other our numbers."

He gritted his teeth. "On the count of three, then." She nodded. Then they both spoke. "One, two, three."

Chuuya lifted his hand to his choker, pulling it down to expose the number on his neck. Across from him, Chizue twisted her neck, letting the light shine on it. They stared at each other in stunned silence.

Chuuya's number was A5158. Chizue's number was A5159.

"You really are him," Chizue breathed, eyes roving over his face, a hand reaching out to him before the chain on her wrist pulled taut. Chuuya himself took in his sister's face, finding identical blue eyes, a familiar nose, the same arch of eyebrows. It was like looking at a younger, female version of himself.

"Chizue?" Chuuya tried the name, words sounding unfamiliar to his ears, yet familiar to his mouth, as if he'd said them before. His sister blinked at him, waiting. "Why, no – how are you still alive? I mean," he tugged at his lock of hair, "Arahabaki created a crater where the facility was, and I'm pretty sure no one except for me survived, but you…?"

"They moved you to a different facility," Chizue wrapped her arms around her legs, eyes cast down. "It was so long ago, I thought, I thought that you might have been just a dream."

Chuuya bit his lip. "How old were you then?"

"Three, I think." She furrowed her brows. "I only vaguely remember some stuff from back then, and I haven't been able to properly keep track of time here. But I guess it's been at least a decade? Um, how, how old are you, nii-san?" Chuuya shook himself out of the stupor he'd been in, when blue eyes stared at his own. "I'm 22 this year." He watched as she bit her lip, lifting her hands to count, while his mind raced.

If Chizue really was only 3 years old when he'd been moved to the other facility and then escaped, that would mean that there was about a 4 year age gap between the two of them, which would mean that his sister was 18 years old this year… and that she'd been stuck in this place for 15 years. He sucked in a breath, suddenly feeling nauseous.

15 years… In all that time, he'd been busy trying to find his place in the world, stuck somewhere between humanity and godhood, wondering whether his existence was meant to be. He hadn't looked back at his days as an experiment after killing Rimbaud and Verlaine, never thinking about whether he might have left someone behind.

It's not your fault. Arahabaki whispered in his mind, making him grit his teeth.

Before he could retaliate, a sudden coldness permeated the cell, making him shiver. Chizue went rigid, back stiff and straight as she stared at the floor. Chuuya found himself following her gaze, tensing as he spotted black tendrils of mist wafting from the floor.

"What's happening?" He looked to his sister, only to find her on her feet. "…Chizue?"

She stared at him fearfully. "They're going to experiment again."

He froze.

"You mean–" He was cut off when the black mist grew bigger and swallowed them both. He cursed and struggled against the chains, feeling a pull on them as they suddenly grew tighter. He felt his spine slam into a hard surface, something clamping onto his neck to hold it down, along with his limbs. By the time his vision cleared of the darkness, he'd been rendered immobile against the restraints. He tried calling on For the Tainted Sorrow, only for silence to greet him where the power once lay humming. He swore mentally. Ability-cancelling restraints. Rare, cost a fortune to buy and a literal life to make. Even the Port Mafia didn't use such restraints, the Boss deeming it too costly to find and purchase them. He'd heard rumors that the government had a few pairs, which could mean that–

"Finally," a voice to his right spoke. "I get a proper reference."

Chuuya immediately tried twisting his head to see who it was, only to be held back by the dratted collar. Biting back a hiss against the pain, he watched with narrowed eyes as a man wearing a mask came into view.

"Who-?" "Quiet," the man interrupted, one hand coming up to hover over Chuuya's immobilized limbs. Chuuya growled at that, then yelped in surprise as the surface he was tied to tilted up, so that he could see his surroundings. He sucked in a breath when he spotted Chizue strapped against another table, surrounded by a bunch of other people in lab coats. Her eyes snapped to his immediately, and she gave him a grimace.

"Just like the sister, I see. Always worried about others, even when they should be worrying more about themselves." Chuuya focused back on the man, suppressing a wince when he poked a needle into his arm to draw blood. "I wonder what it is that makes Nakaharas so resilient. Perhaps you were descended from one of the gods." Chuuya growled lowly throughout the man's soliloquy, until Chizue coughed, pinning him with an anxious look. She shook her head minutely.

The man ignored the silent exchange, withdrawing the syringe. "I wonder if that's the key behind Arahabaki's compatibility with you, A5158," he addressed the mafioso. Chuuya tore his eyes away from his sister to glare at him. "It would be a breakthrough in science to harness the power of a god, to say nothing of tying down the power of Izanami herself."

Chuuya's eyes flicked about the room at that, and his breath caught at the pale white book with ornate detailing displayed on a stand. Before he could give more than a second's glance, the man spoke again, and Chuuya forced himself to look back at him, scowling.

"I'll save you the trouble of asking. My name is Chisaki Kai, and I intend to continue what my predecessors started."

"And that is?"

Gold eyes met his own furious blue ones.

"To make soldiers out of gods."

Note: This fic is no longer a crossover. I'm just using Chisaki Kai because I have no energy to create a new mad scientist.