By the time they finished shopping, the sun had already begun to set.
Their hands were filled with bags—novels, fabric, and a few extra things Marin insisted on buying along the way.
After a short stop at a maid café, the three of them finally decided to head home.
The sky was painted in soft shades of orange and purple as they walked through a quiet park.
The lively noise of Akihabara had long faded behind them, replaced by the gentle rustling of leaves and the cool evening breeze.
"…Today was fun," Marin said, stretching her arms slightly as she walked.
"Yeah," Ren replied. "More productive than I expected."
"Hehe, right? We even got everything we needed!"
Megumi walked beside them, holding a small bag.
"…It was nice," she added quietly.
Marin turned to her with a bright smile. "Right, Kato-chan?"
"…Mm."
A brief silence followed—comfortable, not awkward.
The kind of silence that didn't need to be filled.
Ren glanced at the sky, watching as the light slowly dimmed.
Night was approaching.
Then—
Something felt off.
The usual sounds of the park were gone, not gradually fading but vanishing all at once—no footsteps, no distant chatter, not even the faint rustling of leaves carried by the evening breeze, leaving behind a silence so complete it felt unnatural.
Ren's gaze shifted slightly as he took in the surroundings, his expression tightening just a fraction.
"…Kitagawa-san," he said quietly, his voice low but steady, "do you notice anything strange?"
Marin blinked, still caught between confusion and lingering excitement from earlier. "Eh? Strange—"
Her words cut off abruptly as she finally looked around properly.
"…Huh?"
The park, which had been filled with people just moments ago, was now completely empty, as if everyone had vanished without a trace.
"…Weren't there people here just now?" she asked, her voice unconsciously lowering.
At the same time, a thin layer of fog began to creep in, spreading slowly across the ground like a silent tide, curling around their feet and thickening with each passing second.
Beside him, Megumi Kato took a small step closer, her movement subtle but deliberate, her hand lightly gripping the edge of Ren's sleeve.
"…This feels familiar," she said, her tone calm, yet carrying a quiet tension beneath it.
The atmosphere reminded her of that night—the encounter with the ghoul—and even if her expression remained unchanged, her body told a different story.
Ren didn't respond immediately, his eyes narrowing slightly as he scanned the fog-filled park, his instincts already sounding a quiet warning.
This isn't normal.
The fog thickened further, the streetlights above them flickering faintly as if struggling to remain lit, and the silence that surrounded them began to feel heavy, almost suffocating.
"…Stay close," Ren said at last, his voice calm but firm enough to leave no room for argument.
Marin instinctively moved closer, her earlier cheerful mood completely gone as unease crept into her expression.
"…Aion-kun… what's going on?" she whispered.
Ren exhaled slowly, and for just a brief moment, a faint, almost imperceptible distortion flickered within his crimson eyes.
"…Something's here."
The moment those words left his mouth, a faint sound echoed through the fog—soft, uneven, like something dragging itself across the ground.
Megumi's grip tightened slightly.
Marin froze.
And then, from within the fog, a shape began to form.
What stepped out was no longer human.
Its body was twisted and distorted, limbs stretched at unnatural angles as though something inside it was trying to tear its way free, while dark veins pulsed beneath its skin and a faint, cracked glow flickered from its chest, like a broken core barely holding itself together.
"…W-What is that…?" Marin's voice trembled.
Megumi moved even closer to Ren, her hand still gripping his sleeve.
"…It's not normal," she said quietly.
The creature's head jerked suddenly, then snapped toward them, locking onto their presence as a distorted grin slowly spread across its face.
"He…lp…"
The voice that came out was broken—wrong in a way that made the skin crawl.
It began moving toward them, each step uneven yet deliberate.
Ren exhaled softly, then stepped forward without hesitation, placing himself between the creature and the two girls.
"…Stay behind me."
Marin froze. "Aion-kun—?!"
But Ren didn't look back, his attention fully fixed on the creature in front of him.
Not a ghoul… something else.
Without hesitation, he reached into his pocket and pulled out three folded pieces of paper, each covered in intricate runes and symbols—the same ones he had written the day before.
The creature suddenly lunged forward, its speed unnatural.
Fast.
Too fast.
Ren moved.
With a simple flick, the first paper slipped from his fingers, and the moment it touched the ground, a faint ripple spread outward as the fog shifted and the space around them distorted slightly, as if the world itself had chosen to look away.
No one outside would see.
No one would interfere.
The creature was already upon him, claws reaching—
Another flick.
The second paper activated instantly, and an invisible force snapped into place, freezing the creature mid-motion as its entire body locked, unable to move even an inch.
"…Ghh—"
Its distorted voice struggled, but the restraint held firm.
Ren stepped forward, calm and unhurried, his crimson eyes reflecting the creature's twisted form.
"…You're in the way."
With one final throwing motion, the third paper ignited—not with ordinary fire, but with something deeper, something that didn't simply burn flesh but erased it entirely.
This is the very flame that once tested on SCP-682 and managed to burn 80% its body
The flames spread instantly from within, consuming the creature from the inside out.
"AA—"
It didn't even finish its scream.
Its body collapsed into ash, scattering into nothingness as if it had never existed.
Silence returned.
The fog slowly thinned, and the oppressive atmosphere lifted as the night air returned to normal.
Ren stood still for a moment before turning back.
"…It's fine now."
Marin stared at him, completely frozen.
"…Eh?"
Megumi blinked once, her hand slowly loosening its grip on his sleeve.
"…That was fast."
Ren shrugged lightly.
"Just a small problem."
Behind him, faint traces of ash drifted away in the wind, and for a brief moment, something small cracked—an almost imperceptible sound—before disappearing completely.
Ren narrowed his eyes slightly.
'This looks like a Stray Devil… no, more precisely, a failed reincarnation', he thought, his gaze lingering on where the creature had been.
'A corrupted one.'
What puzzled him, however, was the condition of its body—there had been no visible injuries, no signs of external damage or instability.
It had been… intact.
In most cases, failed reincarnations were dealt with quickly before they could spiral out of control, yet this one had been left alone, as if abandoned.
Letting out a quiet breath, Ren took out another rune paper, this one meant not for combat, but for cleanup.
Even though the creature had been reduced to ash, traces of its presence still lingered—subtle, but detectable to those sensitive to supernatural energy—and that was something he couldn't afford to leave behind.
With a flick of his wrist, he released the paper, watching as it dissolved into fine dust midair.
At first glance, nothing seemed to happen.
But for those who could perceive it, the change was immediate.
The moment the dust scattered, the lingering presence vanished completely, and the atmosphere settled back into its natural state—
As if nothing had ever occurred.
For a few seconds after everything returned to normal, silence lingered between them.
Marin stood still—
Then suddenly—
Her eyes lit up.
"…Wait."
Ren glanced at her.
"…Wait, wait, wait—what was THAT?!" Marin stepped forward, her earlier fear completely gone, replaced with overwhelming excitement. "That was real, right?! Like, actually real?! That wasn't CG or anything, right?!"
Ren paused.
Megumi blinked.
"…You're not scared?" Ren asked.
"Scared?" Marin repeated, then shook her head rapidly. "No way! That was AMAZING!" She clenched her fists slightly, practically bouncing in place. "That was like something straight out of anime! No—better! It was way more real!"
Ren stared at her for a moment.
'…As expected of her.'
Marin leaned in closer, her voice dropping into an excited whisper.
"Aion-kun… what was that thing? And those papers! And the fire! And the whole space going weird—like, what even was that?!"
"…We should talk somewhere else," Ren said calmly.
Marin immediately nodded. "Yes, yes, yes, absolutely!"
Megumi, standing quietly beside them, simply followed along.
"…A café?" she suggested.
Ren gave a small nod.
"Private room."
Not long after, the three of them arrived at a quiet café tucked away from the main street.
After a brief exchange with the staff, they were led into a small private room, separated from the rest of the customers.
The door slid shut.
Silence.
Marin immediately leaned forward across the table, her eyes practically sparkling.
"Okay! I've been waiting—tell me everything!"
Ren sat back in his seat, calm as ever.
Megumi sat beside him, quietly watching.
"…Before I explain," Ren began, "you need to understand something."
Marin straightened slightly, still excited.
"The world isn't as normal as it looks."
"…Yeah," Marin nodded quickly. "I figured that much after just now."
Ren continued, his tone steady.
"What you saw earlier wasn't a one-time thing. Creatures like that exist… hidden from normal people."
Marin listened seriously now, though the excitement in her eyes didn't fade.
"And you?" she asked. "You're not normal either, right?"
Ren paused for a brief moment.
Then—
"…You could say that."
He reached into his pocket and placed one of the rune papers on the table.
Marin's gaze instantly locked onto it.
"These are tools I made," Ren said. "They're not technology… and not exactly magic either."
Megumi glanced at the paper.
"…Something in between?" she asked.
"…Close enough."
Ren leaned back slightly.
"As for that thing earlier…" his eyes narrowed faintly, "…it was something like a failed reincarnation devil. A being that shouldn't exist in that form."
Marin tilted her head.
"…So like… a corrupted character?"
"…That's one way to put it." Said Ren
Marin nodded slowly.
Then—
"…This is so cool."
Ren went silent.
Megumi blinked once.
Marin leaned back in her chair, looking completely satisfied.
"I mean, it's dangerous, yeah—but still! Hidden world, supernatural stuff, secret battles… this is literally every anime setting ever!"
"…You're taking this surprisingly well," Ren said.
Marin grinned.
"Well, I trust you, Aion-kun."
Ren paused slightly at that.
"…Besides," Marin added, resting her chin on her hand, "if you're there, it'll be fine, right?"
Ren didn't answer immediately.
But a faint smile appeared.
"…Yeah," he said simply.
Megumi watched the two of them quietly.
Then spoke.
"…So what happens now?"
Ren's gaze shifted slightly.
"…Now?"
He tapped the rune paper lightly.
"We keep things normal."
A brief pause.
Ren reached into his pocket again.
This time, he didn't take out just one rune paper—
But several.
He placed them neatly on the table.
Marin leaned forward immediately, eyes shining. "Ooh… more items?"
Megumi quietly shifted her gaze toward the papers.
"…These are for you," Ren said.
Both of them paused.
"…Eh?" Marin blinked.
"For us?" Megumi asked.
Ren nodded.
"If something like earlier happens again, you'll need a way to protect yourselves."
Marin's expression softened slightly, though the excitement was still there.
"…Aion-kun."
Ren ignored the tone and continued calmly.
"These are simple to use. You just need to pour a bit of intent into them… or, to put it simply—think about activating them."
He pointed at the first paper.
"This one is a barrier rune. It'll create a temporary shield around you. Strong enough to block most direct attacks."
Marin carefully picked it up, holding it like something precious.
"…So like a defense skill," she murmured.
Ren moved to the next one.
"This is a teleport rune. If things get dangerous, activate it and it'll move you to a safe location."
Megumi tilted her head slightly.
"…Where is 'safe'?"
"…Somewhere away from the threat," Ren replied. "Don't worry, it won't drop you in the middle of nowhere."
"…That's reassuring," Megumi said flatly.
Ren then tapped another paper.
"And this one—"
His tone became slightly more serious.
"—is a signal rune."
Marin blinked. "Signal?"
"If you activate it," Ren said, "I'll know."
A brief pause followed.
"…No matter where I am."
Megumi looked at the paper for a second longer.
"…So it's basically a 'call for help' button."
"…Exactly."
Marin held the papers in both hands, staring at them with a mix of excitement and something softer.
Marin held the rune papers carefully, staring at them with bright, fascinated eyes.
"…This feels kinda unreal," she said with a small laugh. "Like I just got handed something straight out of a fantasy setting."
Ren raised an eyebrow slightly. "You don't like it?"
"No, I love it," Marin said quickly, shaking her head. "It's just… I didn't expect something like this to happen to me."
Ren let out a quiet breath.
"…Then just think of it as insurance."
Marin smiled, gripping the papers a little tighter.
"…Yeah. I will."
Megumi, still holding her share of rune papers, looked down at them briefly before speaking.
"…Thank you."
Her voice was quiet, but genuine.
Ren glanced at her, then looked away slightly.
"…Just don't lose them."
Marin immediately nodded. "No way! I'm definitely keeping these safe!"
She paused—
Then grinned again.
"…But seriously, Aion-kun… this is way too cool."
The atmosphere in the room gradually settled.
The earlier tension had long faded, replaced by a quiet, comfortable calm.
Marin was still fiddling with the rune papers in her hands, occasionally glancing at them like a child with a new toy.
Megumi, on the other hand, simply held hers carefully, her gaze thoughtful.
Ren leaned back slightly in his seat, watching the two of them in silence.
…This should be fine.
After everything they had just experienced, keeping things distant would only feel unnatural.
"…By the way," Ren spoke, breaking the silence.
Marin immediately looked up. "Hm?"
Megumi shifted her gaze toward him as well.
Ren paused for a brief moment, as if considering his words.
Then—
"…You don't have to call me Aion anymore. it just felt...kinda weird"
Both of them blinked.
"…Eh?" Marin tilted her head.
Ren exhaled quietly.
"Ren is fine."
For a second, neither of them responded.
Then—
Marin's eyes lit up.
"Eh—really?!"
She leaned forward slightly, a bright smile spreading across her face.
"Then—Ren-kun?"
Ren gave a small nod.
"Yeah."
"Okay, Ren-kun!" Marin said immediately, clearly pleased, as if she had just unlocked a new achievement.
Megumi watched the exchange quietly before speaking.
"…Then I'll call you Ren too."
Her tone was calm as always, but there was a subtle softness to it.
"Then! Then! If we're doing that—" she said, grinning, "you should call us by our first names too!"
Ren raised an eyebrow slightly.
"…Is that necessary?"
"Of course it is!" Marin puffed her cheeks slightly. "It's only fair, right? We're getting closer and all that!"
Megumi nodded lightly.
"…It would be less formal."
Ren looked at the two of them.
One was smiling brightly, full of energy.
The other was calm, but quietly agreeing.
He paused for a moment.
Then let out a small breath.
"…Kitagawa."
Marin immediately frowned.
"Hey—no fair! That's still last name!"
Ren glanced at her, unimpressed.
"…Marin."
For a brief moment, Marin froze.
Then—
A wide smile spread across her face.
"Okay, I like that!"
She leaned back in her chair, clearly satisfied.
Megumi watched the interaction before speaking again.
"…And me?"
Ren shifted his gaze toward her.
A short pause.
"…Megumi."
Her expression didn't change much.
But her eyes softened—just slightly.
"…That works."
A quiet silence followed.
But unlike before, it felt different.
Closer.
Warmer.
Marin suddenly giggled.
"Hehe… this kinda feels like one of those scenes, you know?"
Ren glanced at her. "…Ero scenes?"
"NO! You know… it's like when characters beat a really strong boss together," she said, smiling to herself.
"After that, the party just… feels closer, right?"
"…You're overthinking it," Ren replied flatly.
"Am not!" Marin shot back immediately. "This is important character development!"
Megumi rested her chin lightly on her hand.
"…She's not entirely wrong."
Ren sighed softly, though there was no real annoyance behind it.
"…Whatever you say."
Marin grinned.
While Megumi shown a faint smile