The sound of footsteps echoed off the walls of towering skyscrapers, and the scent of street vendors filled the air. Ijin scanned the crowds for any sign of danger, while Nezuko's curious gaze flitted around, taking in the sights and sounds of the city.
After several minutes of weaving through the crowded streets, Ijin led Nezuko down a dark alleyway, away from main thoroughfare. The shadows grew thicker, and the only sound was the distant hum of machinery in the distance. Ijin stopped in front of an unremarkable metal door, and Nezuko looked up at him, confused.
"This is it," Ijin said, placing his hand on a scanner beside the door. A small green light flickered on the panel, and the door slid open with a hiss of hydraulics.
Inside was a narrow, dimly lit passageway, leading deeper into the heart of the city. The air was cool and musty, and the sound of dripping water echoed through the narrow tunnel. Ijin led the way, his footsteps echoing on the concrete floor. Nezuko followed close behind, her hand gripping his tightly.
"Okay, no more hand holding," Ijin pulled his hand free. "Just follow me and you won't get lost."
The passageway twisted and turned, leading deeper into the city's underground maze. The walls were slick with moisture, and the occasional flicker of a dim light provided the only illumination. After what felt like hours, Ijin led Nezuko to a metal door. Ijin pressed his hand to a scanner beside the door, and a soft beep signaled his authorization. The door slid open, revealing the gleaming white walls of the lab beyond with a certain individual already inside.
Dr. Eris Nova stood before the array of monitors; her piercing gaze fixed intently on the scrolling lines of code. Her lean frame was clad in a skin-tight, silver bodysuit that shimmered in the harsh neon lighting of the lab. The suit hugged her curves and accentuated her lithe figure. Her sharp features were set in a focused expression, and a wild shock of fiery red hair cascaded around her face like a mane.
To any who looked upon her, she was a striking figure, a vision of sleek silver and dark intensity. But to those who knew her work, she was something far more dangerous - a genius driven to the brink of madness, with a mind that could bend the world to her twisted will.
"Ijin, long time no see," she drawled, turning around to face her visitor. Her smirk faded as she noticed the little kimono-clad girl standing beside him. "Oh? Who's the girl?"
Ijin's reply was blunt. "Her name is Nezuko. She's a demon."
Dr. Nova raised an eyebrow, skeptical. "I didn't take you for a joker, Ijin."
After a moment of silence, she knew something was off. "Wait, you mean to tell me that this cute, little girl is of the same species as that ugly thing you sent me?"
The boy remained unfazed. "Both identified themselves as a 'demon' to me. I'm just taking their word for it."
Dr. Nova approached the little girl, scrutinizing her with a critical eye. Nezuko looked up at her with wide, confused eyes. "Seriously?" the doctor said, incredulous. "She looks very human and docile."
Ijin stepped forward, positioning himself between Nezuko and the scientist. The violet hue of his eyes glinted with a dangerous edge. "I didn't bring her here to be your lab rat," he said, his voice low and threatening. "If you harm her, you will regret it."
Dr. Nova took a step back, visibly taken aback by his protective stance. "Well, this is a rare sight," she mused, a sly grin spreading across her features. "You, of all people, are protecting someone?" She burst into laughter, momentarily disarmed by the absurdity of the situation.
Her mind was already working through the possibilities of what she could do with a demon specimen as unique as Nezuko. She could feel a shiver of excitement run through her as she considered the potential of what she could learn from studying her. But Ijin's warning stopped her in her tracks. She had never seen him so fierce, his violet eyes burning with a dangerous intensity. It was clear that he was not joking about protecting the demon girl.
Dr. Nova raised an eyebrow, studying Ijin carefully. "You're serious, aren't you? You really care about this little demon."
"I already gave you a lab rat. Just tell me what you've learned so far," Ijin said sternly, refusing to be teased.
"You're no fun," the woman sighed. She turned on her heel and walked down the sterile, metallic hallway, her silver bodysuit reflecting the harsh, artificial lighting. Ijin and Nezuko followed behind her, their footsteps echoing in the quiet space. Nezuko's eyes wandered around, unsure of what to make of this strange new environment.
As they entered a room at the end of the hallway, Dr. Nova gestured towards a large, transparent cylindrical chamber filled with a cloudy, ice-blue liquid that dominated the center of the space. Within the chamber was a figure that Ijin immediately recognized: the demon that he had fought against just last night.
The demon was suspended in a cryogenically frozen state, its body preserved in a state of suspended animation. Its features were twisted in a grimace of pain. Sickly grey skin stretched over its muscles and bones, emphasizing its unnatural state. Ijin's frustration boiled over as he recalled his previous encounter with the demon who was reduced to an unrecognizable mess. "I decimated this thing with my car, and it still regenerated!?" he exclaimed, turning to Dr. Nova with a furrowed brow. "Doesn't this violate the Conservation of Matter? Where the hell did all that mass come from?"
Dr. Nova explained, "Energy and mass are interchangeable. If this demon has to ability to convert energy into mass, it's certainly possible to regenerate from seemingly nothing." Her explanation did little to soothe Ijin's confusion, let alone Nezuko's. The little girl blinked in confusion, not comprehending the concepts being thrown around.
Ijin's next question was equally exasperated, "And where the hell is it getting the energy from? How does this not violate the Conservation of Energy?"
Dr. Nova's admittance of uncertainty was the only answer she could offer, "That – I have yet to figure out. As far as I can tell, this creature can seemingly regenerate indefinitely, but there are limits."
"What limits?" the boy pressed on.
"I'm talking about the rate of its regeneration. Over time, that rate does slow down. To put it simply, if the energy it expends outpaces the energy it regains, even this demon will experience fatigue. They may have an infinite supply of energy, but the rate of their energy input is very much finite."
"That's not much of weakness," he said in a disappointed tone.
"Ijin, upon sequencing this demon's DNA, I learned something quite interesting," the woman began walking towards separate computer to generate a holographic screen. "The DNA has a high percent match to a certain resident of Nexus City. Furthermore, his blood contains the DNA of someone else who isn't in our database. In other words, I found two separate DNA sequences in this creature's blood. This demon you sent me, I believe he was once a human being – a resident of this city. My theory is that someone else's DNA infested his body, triggering a massive mutation."
As proof, the holographic screen displayed charts of the DNA sequences, revealing a high percentage match to a Nexus City resident, and the presence of another unidentified DNA.
Nezuko lightly nudged the boy and asked a very basic question, "What is DNA?" Everything that was discussed so far had entered one ear and out the other.
Dr. Nova was the one to explain to the young girl, "DNA is like a recipe that tells your body how to grow and develop. It contains all the instructions on how to create you. It determines all of your characteristics, such as your eye color, hair color, and even your personality to some degree."
Nezuko nodded. Although she could understand and follow what was said to her, she found it miraculous that such a 'recipe' even existed. Such a concept did not exist in her world where the level of technology was so unsophisticated that DNA hadn't even been discovered yet.
The woman swiped her hand across the air, and a series of holographic screens popped up in front of her. They displayed recent news reports from Nexus City, all relating to the same disturbing trend: a string of gruesome crimes taking place at night. "Reports of monsters consuming human flesh and blood have been on the rise in Nexus City," Dr. Nova said, her voice grim. "The police are investigating, but so far, they have not been able to catch the culprits."
The room was filled with tension as the holographic screens flickered with images of gruesome crime scenes of torn flesh and bloodied streets, all occurring at night in Nexus City. The news reports were filled with tales of demons consuming human flesh and blood, leaving behind a trail of destruction and fear in their wake. The air in the room grew heavy as the weight of the situation began to sink in for Ijin.
The woman looked at the boy with a grin, "Ijin, if I recall correctly, you mentioned that the demon that attacked you last night said he wanted to eat you." Her grin twisted into a sinister expression as she seemed almost pleased with the news.
Suddenly, Nezuko widened her eyes in realization, remembering what Ijin said to her this morning. She looked at the chamber more carefully, and she can confirm that it indeed contained a demon just like the ones that could be found in her own world. Did demons simply exist in this world just like her own? And more importantly, she had just learned that Ijin was truly attacked by such a demon last night while she was asleep. She didn't believe him at first, but the proof was now right before her eyes. This must be how he got injured.
Ijin kept his eyes glued to the recent new report and replied, "That's right. You mean to tell me that there are more of these 'demons' out there in this city?"
"Yes," said the woman, drawing out the word with relish. "I've never seen anything quite like this. If what the news say is true, then we are likely the first ones to have successfully captured and detained a demon." She gestured towards the cryogenic chamber, where the demon lay frozen and silent.
She turned her attention back towards Ijin, her voice taking on a sharp edge. "Now, Ijin. Tell me…," she said, pointing towards Nezuko with a sinister glare. "How can you be so calm around that thing? If she's truly a demon, she might try to eat us too. Don't be deceived just because it's cute. It's possible that it's playing the long game, trying to associate with as many livestock as possible."
As Dr. Nova spoke, her tone grew darker, and her sinister glare towards Nezuko intensified. The girl felt a lump form in her throat as she struggled to speak. It was clear that Dr. Nova was trying to turn Ijin against her, using fear and suspicion to make him doubt the demon girl. "I…," she turned towards Ijin, afraid of what he would think. Was she really going to be seen as nothing more than a monster, even in this world where she knew almost no one?
Ijin was lost in thought, weighing the possibility of Nezuko becoming a threat to his life. He knew he couldn't rule it out, especially given the recent news reports of demon attacks in the city.
"When exactly did you meet this demon girl?" Dr. Nova's voice cut through the silence, sharp as a knife. Nezuko's fear was palpable as the woman pressed on. The girl's heart was racing as she looked to Ijin for support, pleading with her eyes for him to believe in her innocence.
"Last night," Ijin replied, his voice low and uncertain.
"Oh?" Dr. Nova's grin widened. "The same night when you were attacked by another demon? Is it not possible for these two demons to have conspired together? For all we know, this girl may have sent the other demon towards your location. You can't trust her, Ijin. Because if you do, it may cost us our lives. You know better than anyone else just how unkillable these demons seem to be."
Nezuko felt a cold sweat break out on her forehead as she listened to Dr. Nova's words. She wanted to protest, to tell them that she had nothing to do with the attack, but she feared that it would be useless, that they had already made up their minds about her. "Ijin," she looked at him with pleading eyes, "I'm not the same as the other demons. I've never eaten a single human in my life!"
"And how can we trust you?" Dr. Nova exclaimed, raising her voice, causing the girl to flinch.
"That's enough," the boy raised up his hand for them to stop. "Dr. Nova, I know what you're trying to do. You know very well that I can detect when someone is lying. Nezuko hasn't told me a single lie. You're just trying to frame her as an enemy because you want her as your test subject."
Dr. Nova laughed and eased up. "Oh well, it was worth a shot," she shrugged, admitting that he was correct. Her admission of defeat was a small relief in the face of the overwhelming fear and uncertainty of the situation. Nezuko felt a glimmer of hope.
Returning to the screens, Ijin asked, "If these demons are so unkillable, why do they only hunt humans at night? Are they nocturnal?" He had yet to come across a demon-related event taking place during the day.
"Sunlight," Nezuko answered simply. "Demons will burn to ashes from sunlight."
"Sunlight?" Ijin raised an eyebrow. "We came here in broad daylight, and you seemed just fine." He could tell that she wasn't lying, but it contradicted the fact that Nezuko could walk under the sun through the city.
"The sun doesn't affect me anymore. I overcame it," she explained.
Ijin and Dr. Nova looked at each other in surprise. It was new information to them.
"Fascinating," Dr. Nova said. "Do you know why demons are weak to sunlight?"
The girl shook her head, "No, I don't."
Ijin was cautious about getting his hopes up. "Doesn't this mean that the rest of the demons will eventually be immune to the sun as well?" If Nezuko could achieve this, what was stopping other demons from doing the same?
Nezuko answered, "I don't know of any other demons who overcame the sun. It has just been me."
Dr. Nova was now curious. "If you haven't eaten any humans in your life, what do you eat?"
"I don't need to eat," said Nezuko.
"Then where do you get your energy from? It clearly isn't photosynthesis," Dr. Nova asked.
"Sleep!" Nezuko answered proudly.
Dr. Nova turned towards Ijin. The boy simply shrugged, "I asked her the same thing. She isn't lying. I haven't seen her eat anything since I met her. I offered her food, but she declined."
"The thing is…," Dr. Nova explained. "Eating humans wouldn't give enough calories to regenerate a limb. It'd be one thing if demons can directly convert the mass of what they ingest into energy. But if that were the case, I don't see why they would exclusively eat humans. If this girl doesn't even eat anything at all, that disproves the notion of their energy coming from what they ingest."
"Dr. Nova," Ijin called to her attention before making a request. "Would you be able to make me some weapons in case I run into more demons?"
"That's no problem at all. I'll have to design them first before using the 3D Printer," the woman answered nonchalantly.
Nezuko gently prodded the boy with a curious question, "What's a 3D Printer?" Her innocent expression betrayed her complete lack of familiarity with modern technology.
Intrigued by her limited knowledge, Ijin pulled out his smartphone and illuminated the screen to demonstrate its features. "Um…, out of curiosity, do you know what this is?"
The girl shook her head. "I've seen lots of colorful lights since I came here." She was referring to the neon signs that the city would have, mistaking what the boy was holding as nothing more than another source of those colorful lights.
"Do you know what a computer is?" Ijin asked.
Again, she shook her head in confusion.
"Could you describe what technology is like in your world?"
She placed a hand on her chin, tilting her head and trying to find the words to explain it. "I lived in the in the mountains in a small village. We sold charcoal."
"Charcoal!?" Ijin was surprised by how outdated that type of fuel source was.
Dr. Nova explained, "Charcoal is usually obtained through pyrolysis. You heat up organic materials such as wood in the absence of oxygen to break down the molecules and leave behind carbon-rich materials."
"Anything else?" Ijin asked the girl for more examples.
"Hmm," Nezuko reflected back on her past. "I remember being on a train for the first time."
"Was there steam coming out of that train?" Dr. Nova asked.
"Yes!" the girl nodded.
"That train probably used charcoal as its fuel source," the woman concluded but was the left puzzled. "Hm? Which country in this day and age still uses steam locomotives?"
"Oh, she said that she came from a different world," Ijin explained.
"Say what?" Dr. Nova couldn't believe that this boy hadn't detect a single lie from this girl. "Based on what she described so far, I'd estimate that our level of technology is about 200 years ahead of her world."
"T-Two-hundred years!?" Nezuko exclaimed.