Sure thing. Nasuverse/Noir crossover with genderbent Nanaya Shiki? Let's have a look here
For all the wonders of the modern age, the world was filled with shadows: places where odd beings lurked, places that had been abandoned by the light of civilization, places where the twin illusions of order and progress had long given way to decay.
Some were in the usual places - ghost towns, sites of natural disasters, crow and carrion-ridden fields of battle. Yet some could be found in stranger locales - in otherwise peaceful parks, in the middle of the ocean, or, in this case, the heart of a great city. The area currently in question was a massive abandoned construction site, once set aside for some new industrial development that had promised to pump vitality into the city. However, for one reason or another, whether it was lack of funding, inability to navigate the treacherous waters of bureaucracy, or sheer incompetence, it was now a skeletal wreck laying bare to the sky, its exposed steel bones rusting in the air.
Through this complex ran Tohno Shiki’s route home.
Some said that the site was dangerous, that unsavoury people clung about it, but Tohno didn’t care.
She doubted anybody would miss her if anything happened anyway. Sure, she was pretty, but not notably so. She didn’t stand out in school. She didn’t stand out in extracurriculars. She barely even had any friends.
Well, she thought, there's Arihiko, but he's just one man. He hardly counts.
And so she found herself wandering through the abandoned building on her way home, with no one to question why a small girl was in such a place. Why would there be? It was abandoned, after all.
Still, there were some who took...an interest.
She emerged into what might have been a large room, though it was unfinished like everything else. Looking up gave her a view of the red sky bearing down through truncated beams and one-sided rebar. Looking down...she had to blink to be sure her eyes did not deceive, for when she looked down again, a massive man in an ill-fitting black suit stood before her like a Germanic mountain. A fearful glance around her told her that there was more than one: that figures in black surrounded her on all sides, five in total.
Not thugs, not drug dealers, not gangsters…these were something completely different. Men that, from their stance, did not mean to posture or show off, but to accomplish a mission.
Paralyzed by fear, she stood fixed to the spot as they closed in on her. Her panicked breathing echoed throughout the space, accompanied by the stomp of shoes and…and a sound she shouldn’t have been able to recognize. The sound of knives being unsheathed. From behind her, one of the men clamped his hand on her shoulder, in a prelude to a strike.
Instinct took over. On reflex, without consciously knowing what she was about to do, Tohno turned, the sudden movement breaking the man’s grip on her. As his hand grasped empty air, she whirled about, seizing his wrist in her left hand and snapping her right out, striking him directly on the outside of his arm, at the elbow.
A crack like a gunshot echoed throughout the room; the man’s arm snapped clean in half at the joint.
The ring of metal being dropped followed it, as instinct drove the man to clutch his injured arm as opposed to retaining his weapon – a critical - no, fatal - mistake. Leaning back and down, Tohno easily took hold of the knife, snapping it forwards in a reverse grip that cleanly slit his throat.
In shock, the man’s comrades could only stare in silence as he fell to the floor like a puppet with strings cut, aspirating blood and air in a pink mist. At that instant, they knew that they had gravely underestimated the girl. They should have guessed. Why would so many of them have been sent to take out a teenager, if she wasn’t dangerous? But what was done was done, and they were woefully unprepared for what was about to follow.
Still, they had a mission, so they reached into their jackets to draw their blades, in a vain attempt to defend themselves.
Maybe if they hadn’t done that, they could have gotten away.
Maybe Tohno’s killer instinct would have subsided, and she would have been floored from the shock of her sudden action. Maybe she would have sunk to her knees in despair, kneeling in an expanding pool of blood, and they could have taken advantage of that. Maybe...but it was far too late for maybes.
The moment their hands reached for weapons, Tohno moved, knife blurring in a series of precise, surgical strikes.
Only one or two blows were landed on each man: after all, with four of them and one of her, she had not the time for more. But it was enough, as the strikes hit major arteries, tendons, anything that would instantly slow a man. The simple sequence didn’t eliminate them, but it did buy her time.
And time was all she needed.
The large German, kneeling as a result of his slit hamstring, saw a blur of metal approaching him from the side before the tip of Tohno’s knife punched through the thin side of his skull, instantly killing him. The man to his right swung wildly, a blow that Tohno easily ducked under, with a quick move of her arm jerking his head back beyond its limits, shattering his neck instantly.
Shunting his body to the side at an approaching enemy, she dashed sideways, knocking the feet out from under another with a swift kick, ending his life with a clean stab between the ribs, puncturing his heart.
Throwing his fallen comrade off him, the last man looked around the room in fear.
He was the only one left alive - the rest of his team were dead, annihilated by that blood-soaked demon.
In that moment, discipline broke, and the man ran, making for the exit, seeking to at least save his own skin and warn his employer.
Frankly, that he expected that to work was almost comical. Before he took two steps, Tohno’s eyes were on him, staring with singleminded focus at his back. He took a third step as she spun her knife, her arm rearing back to strike.
He didn't have time for a fourth, for the moment he tried, her blade buried itself in his kidney, sending him sprawling to the floor.
For a fleeting instant, he intended to plead for his life, but a shoe to the neck ended that.
Then it was over.
She stood in the field of bodies, arms soaked with blood as she stared down at her victims. And just as abruptly as it had come upon her, the demon inside her disappeared, leaving her a normal girl.
A scared little girl in a field of corpses.
With a snap, she bolted for an exit.
She raced down empty hallways, wondering why, what, where, when, how? What had happened back there? Where had that instinct come from? She was… was she a murderer? Why were those men after her? How...the questions kept echoing in her mind as her feet pounded the pavement, running somewhere, anywhere but here.
Arriving at an exit, she made a final push, trying to get away from that nightmare.
But she could not, as the exit was blocked.
Barring the way to freedom stood another girl, one barely a few years older than her, dressed in a style dead long ago: a white kimono, covered by a red leather jacket. Her jagged-cut hair, in addition to the odd choice of clothing, suggested a person who could care less for the rest of the world. But none of that caught Tohno's attention. What did were the eyes. Dead pools of grey that could not lack any more emotion than they already did. Unreflecting mirrors, windows to the void, to an infinite abyss.
And the abyss was staring into her.
A pained scream escaped her lips. “Wh-who are you?!”
The woman grinned back ferally.
“Who are you? Do you know anything? About yourself?”
How? Tohno wondered. How did she know? It was true: past four years ago, her mind was a blank. No memory existed of her childhood, of parents… just a memory of waking up to a blank ceiling.
Her face showed her thoughts plainly, as the other continued. “Do you want to know?”
“I don’t know… nobody knows!” Tohno screamed back. “It’s lost!”
The woman made a small scoffing noise, reaching for something inside her jacket. She held up the object. A small folding knife, made from black lacquered wood, unmarked and unnotable, save for a spiral metal hinge and a few characters inscribed on the side.
Fire and screams on the moonlit night. Shouts, a forest and building burning down around her. Fear, death. Blood. A knife fallen in the night.
“How do you…” Tohno’s voice was incredulous. How could it be? It was an object she’d only ever seen in a nightmare, only within her mind.
“I can show you your past. Well, not that easily, and I don’t know all of it, but I know how to reach it. Wanna come with me?”
“I have a life… friends… school…”
The woman gave a jerk of her head. “Back there. There are five men that you killed. You think that you can escape that? They’re coming for you. I know how to avoid them. Stay here, and spend the rest of your life a ghost in prison. Or come with me.” Having made her speech, she turned, walking away without an apparent care.
She was right, Tohno thought. What did she really have here? A false life, without any connection to the rest of the world… and a jail cell waiting for her. It would hurt Arihiko… but, but it was not enough to convince her to stay. That woman knew. She knew what lay beyond four years ago.
Tohno ran to catch up.
Comments: On the whole, pretty good. You could use a bit more work on flow and breaking up paragraphs to emphasize certain sentences or images, but you're getting there. Keep at it, and I look forward to seeing more.