Chương 13: Chapter 12: Hidden Beneath the System

I stand near the doorway for a moment longer than necessary, just watching them. That alone is already a bad sign. Every time I hesitate before leaving, it usually means something is about to go wrong—not immediately, not obviously, but eventually. The kind of wrong that starts small, looks manageable, and then somehow escalates into something that requires damage control… or a new curtain. I exhale slowly and turn toward them, deciding that standing here overthinking it isn't going to improve anything.

"Alright," I say, keeping my tone firm but not strict.

"Papa is going out for a bit." That gets their attention immediately. Karin straightens up on Ruruka's lap, her eyes already bright with curiosity.

"Where are you going?" she asks, leaning forward like she's about to negotiate her way into coming with me.

"Work," I reply.

"Dungeon?" she follows up instantly, too fast, too accurate.

"Yes," I say.

"Can I go?" she asks.

"No," I answer, equally fast. She pouts, clearly offended by the lack of discussion. Hikari raises her hand like this is a formal meeting.

"Hikari wants to go too," she says.

"Also no," I reply.

"Okay," she says. That was easier than expected, which is usually suspicious, but I'll take it. Ruri, as always, doesn't argue. She simply shifts slightly closer to Ruruka and sits properly, hands folded neatly on her lap.

"We will behave," she says. I look at her for a second longer than necessary. Reliable. Consistent. My sanity anchor. I nod once.

"Good," I say, before shifting my gaze to all three of them.

"Listen carefully. While I'm gone, you stay here, you listen to your aunt, and you don't cause any trouble." Karin raises her hand enthusiastically.

"Yes!" That confidence concerns me. Hikari nods.

"Hikari will behave." That is… less reliable, but still acceptable. Ruri nods again, calm as ever.

"We understand, Papa." I pause, weighing trust against experience. Then I sigh.

"I'm trusting you," I add, mostly for my own peace of mind. Karin grins. That does not help. I turn my attention to Ruruka. She's sitting comfortably, one arm resting lightly around Karin to keep her from wandering off, her posture relaxed but alert. Even at rest, she looks like she could react to anything instantly, which is exactly why she's here.

"Don't worry, Nii-sama," she says.

"I'll take care of your kids." I look at her. Then at them. Then back at her again, just to make sure I'm not missing anything obvious.

"Please do," I say. She smirks slightly.

"You say that like you don't trust me."

"I trust you," I reply.

"I don't trust the situation." Karin raises her hand again, very proud of herself.

"We are the situation," she says. I don't respond. Because she's not wrong. I let out one last breath before turning toward the door. There's a brief moment where I consider saying something else—another reminder, another warning—but I stop myself. At this point, repeating it won't change the outcome. I open the door and step outside. The air feels different immediately—quieter, less chaotic, like the moment you step away from a noisy room and realize how loud it actually was.

I take a few steps away from the apartment before pulling out my phone and glancing at the coordinates Ruruka sent earlier. It's close. Closer than I expected, which explains how she managed to get here so quickly.

"Convenient," I mutter. I start walking. The path leads toward a more secluded area near the outskirts, where the buildings thin out and the surroundings become quieter, less crowded. The usual city noise fades into the background, replaced by something more open and still. I stop once I'm far enough. No people. No witnesses. Good. I lift my hand slightly, letting a faint glow of mana gather at my fingertips. My eyes shift subtly, a faint blue hue forming as I focus.

"Arcane Resonance," I murmur under my breath.

"Origin Element." The air responds immediately. Space bends—not dramatically, not violently, but with a quiet distortion that feels controlled, precise. Like something is being adjusted rather than broken.

"Spatial manipulation," I continue.

"Warp." A distortion forms in front of me, expanding outward into a gate-like structure. Its surface ripples like liquid glass, reflecting a different space entirely. The outskirts. Near the dungeon. The space folds cleanly as I step through, the transition so smooth it barely registers beyond a shift in pressure and temperature. One moment I'm standing in a quiet street, and the next I'm somewhere else entirely, the air noticeably cooler and heavier as it settles around me.

I take a step forward as the portal closes behind me without a trace, leaving no sign it was ever there, and lift my gaze toward the dungeon entrance just ahead. As expected, it's empty. No Hunters. No guards. No visible activity. Just silence—controlled, deliberate, and intentional in a way that immediately tells me this isn't natural inactivity. That tells me everything I need to know.

"Sealed," I mutter under my breath, already recognizing Aaron's work in the precision of it. Efficient, as always. I walk closer, studying the entrance carefully. Faint traces of barrier magic linger in the air, subtle but layered, designed to keep unauthorized people out without drawing unnecessary attention. It's clean, controlled, and exactly what I would expect from him. I reach out slightly, letting my mana brush against the barrier.

The response is immediate but controlled—it doesn't flare, doesn't resist, doesn't attempt to repel me. Instead, it acknowledges me. Not aggressively. Not defensively. Just enough to confirm I'm there before deciding not to interfere. Or rather… it chooses not to stop me.

"Convenient," I say again, quieter this time. Before stepping in, I pull out my phone and type a quick message. I'm at the dungeon. I'll be inspecting it. If something goes wrong, I'll destroy it. I stare at the screen for a second, not because I'm hesitating, but because I'm considering whether I need to say anything else. I don't. I send it without waiting for a reply. Sliding the phone back into my pocket, I glance up at the sky.

The light is fading now, the color shifting toward evening, stretching shadows across the ground.

"I should be quick," I mutter, not out of concern, but because I don't like dragging things out unnecessarily. I return my attention to the dungeon entrance and step forward. The moment I cross the threshold, the environment shifts completely. The outside world doesn't just disappear—it feels like it's cut off, replaced instantly by something else as the air changes, becoming denser, colder, and far more controlled than before. It's a labyrinth-type dungeon. Just like Ruruka said.

I stand there for a moment, letting my senses adjust as I take in the surroundings. The walls are uneven, carved from stone but not naturally—constructed, deliberate. The pathways ahead twist and branch, disappearing into shadow like they were designed to mislead. Quiet. Too quiet. I take a step forward. Then another. And as I move deeper into the dungeon, one thought settles firmly in my mind. Stolen from its original source, this story is not meant to be on Amazon; report any sightings. Something is wrong here.

And I'm about to find out what. The deeper I go, the quieter it gets, but it isn't the natural kind of quiet you expect from an area that's already been cleared. Instead, it feels deliberate and controlled, less like simple absence and more like suppression, as if the dungeon itself is holding its breath and waiting for something.

"… That's already suspicious," I mutter under my breath, more to confirm my thoughts than anything else. I continue walking at a steady pace, not rushing, not slowing down either, letting my senses adjust to the environment as I move through the labyrinth's twisting pathways. The structure matches what Ruruka described—branching corridors, uneven stonework, deliberate design meant to confuse and delay anyone moving through it without direction. At first glance, everything looks normal, which is exactly the problem.

I stop briefly at an intersection, letting my gaze sweep across each path.

"No movement, no sound… nothing reacting," I say quietly.

"That's not how a dungeon behaves." Even after a raid, there should be something left behind—stragglers, residual monsters, or at the very least some form of response to a new presence entering the dungeon. A system like this doesn't just go completely silent unless something forces it to.

"So either something cleared everything… or something doesn't want anything here," I add. I exhale slowly and lift my hand slightly, gathering mana with practiced ease.

"Origin Magic," I murmur.

"Light element… Illuminate." Light spreads outward from my position in a controlled expansion, flowing through the surrounding corridors like a quiet tide. Shadows retreat instantly, every corner and pathway revealed under a steady glow. I take a slow look around.

"If something's here, this should force a reaction," I say. There is still nothing—no movement, no reaction, and no distortion anywhere within the illuminated area.

"…Or not," I add dryly. I let the light dim slightly and layer another spell over it.

"Origin Magic. Spatial element… Spatial Awareness." The world doesn't change visually, but my perception shifts completely. Mana flows map themselves across my senses, turning the entire area into a network of presence and absence. I wait, letting the detection settle fully before tilting my head slightly.

"…That's it?" I say, clearly unimpressed. There are faint residual traces, but no active signals, no movement, and nothing alive within range. I lower my hand slowly.

"That's not normal," I repeat, this time with more certainty.

"Even for a cleared dungeon, this is excessive." I take a step forward again, thinking through the possibilities.

"Ruruka wouldn't over-clear like this," I mutter.

"It's inefficient… and she hates wasting time." Which means this isn't her doing.

"So something else interfered," I conclude quietly. I activate another spell without hesitation.

"Origin Magic. Wind element… Gale Step." My body lightens as I move forward at speed, turning corners smoothly, letting spatial awareness guide me.

"Let's see how far this emptiness goes," I say. One hallway leads into another, then another, the structure repeating in a way that should feel confusing—but doesn't. And the more I move, the more obvious it becomes. There are far too few signs of life—no broken walls from monster activity, no lingering mana fluctuations, no territorial markers, and nothing that suggests this place is, or ever was, functioning normally. It leaves behind only a quiet, unnatural emptiness. I slow down as I approach a wider passage.

"Boss room," I say quietly. I step inside. The space opens up immediately, far larger than the corridors, with a central platform where the boss should have been. And yet, it's completely empty—no corpse, no remains, and more importantly, no core. I stop in the center, scanning the area more carefully.

"…Yeah, that's definitely wrong," I say. Even if the boss was destroyed completely, the core should have manifested. That's not optional—it's part of the system itself.

"So the system failed… or something interrupted it," I add. My gaze shifts toward the throne at the far end. It looks intact. Untouched.

"That's even worse," I mutter.

"There should be damage here." Ruruka would have fought here. There should be signs of impact—something to indicate a battle took place. But there isn't.

"You're hiding something," I say quietly, narrowing my eyes. I increase the output of my spatial awareness, forcing it deeper into the structure.

"Don't make me dig for it," I add. For a moment, nothing responds. Then something finally registers. I stop instantly.

"There you are," I say, voice lowering slightly. The signal isn't behind the throne—it's beyond it, deeper, concealed deliberately.

"Hidden layer… or artificial concealment," I mutter.

"Either way, that's not standard dungeon behavior." I raise my hand without hesitation.

"Arcane Resonance… Arcane Blast." The spell forms instantly and launches forward, striking the throne directly. Stone shatters on impact, and the structure collapses inward as the blast tears through it, exposing what lies beyond. Dust settles slowly while debris falls in uneven fragments. I step forward slightly, a small grin forming despite myself.

"So that's how it is, huh?" I say. I tilt my head, eyes narrowing as the hidden structure comes into view.

"…Yeah," I murmur.

"Now it's getting interesting."

RURUKA'S POV I still can't believe this. Out of all the possibilities I've ever considered in my life—career progression, rank promotions, dangerous raids, even dying in a dungeon at some point—not once did I think I'd walk into my brother's apartment and find him… raising children. Not adopting or babysitting, but actually raising them, and somehow managing to do it overnight.

I let out a slow sigh as I lean back slightly on the couch, adjusting my posture just enough to stay comfortable without disturbing the small weight currently sitting on my lap. Karin is completely absorbed in the anime playing in front of us, her eyes shining as she cheers for the protagonist like her emotional investment is personally tied to the outcome.

"Do it! Do it!" she says excitedly, leaning forward with just enough force that I have to lightly hold her in place before she slides off.

"Stay still," I tell her, keeping my tone firm but not harsh.

"But this is the important part, Auntie!" she insists, still trying to lean forward like that will somehow improve the outcome.

"Every part is important to you," I reply, unimpressed. She pauses for a moment, clearly thinking about that. Then nods seriously.

"Yes." …Fair enough. I shake my head slightly, though I can't quite suppress the faintest hint of amusement. To my right, Hikari has already fallen asleep at some point, still holding a half-eaten sandwich in her hand. I glance at it, then at her face, then back at the sandwich again. She's peaceful—too peaceful, in fact, in the kind of way that makes me instinctively suspicious.

"You were loud five seconds ago," I mutter under my breath as I carefully take the sandwich from her hand before it falls.

"How do you even fall asleep this fast?" There's no response. Of course there isn't. I set the sandwich aside.

"At least one of you stopped moving," I add quietly. On my other side, Ruri is sitting properly, just like she always does, her posture straight and composed, hands resting neatly on her lap. If I didn't know better, I'd think she was attending some kind of formal meeting instead of watching anime. But her eyes are focused. Bright. Engaged. She's enjoying it. She's just doing it… properly. I glance at her for a moment longer than necessary. Then I notice it. She's tugging lightly at my sleeve.

I shift my attention fully to her.

"What is it?" I ask, my tone softening slightly without me meaning to. She hesitates for a second before speaking.

"Auntie…" she says quietly. There's something off in her tone. I recognize it immediately. There's concern in her voice, subtle but unmistakable.

"Yes?" I respond, a bit gentler now. She looks down briefly, then back up at me, her expression careful but honest.

"Is Papa going to be okay?" Ah… that question. I lean back slightly, letting it settle for a moment before answering. There are a lot of ways I could respond to that, and most of them would either worry her more or not answer anything at all. The honest answer is complicated, but the practical answer is simple, and with children, simple is usually better. I let out a small breath.

"If something is actually capable of threatening your Papa," I begin slowly, choosing my words carefully, "then there are only two possibilities." She listens closely, and somehow Karin is also listening now, even while pretending she isn't.

"Either it's your Papa himself," I continue, "or something on the level of a god," I explain, keeping my tone even despite the weight of what I'm actually saying. Karin's eyes widen immediately, but not with fear—if anything, she looks even more excited.

"A god?" she repeats, leaning forward slightly like this just made things more interesting.

"Like the ones in stories? The really strong ones?" she adds quickly, unable to hold back her curiosity.

"Something like that," I reply, glancing at her briefly.

"Yes," I answer calmly, watching her reaction.

"Can Papa fight gods?" she asks without hesitation. Hikari, despite being half-asleep, suddenly murmurs, "Papa fights everything," as if stating a universal truth before settling again. I pause for a brief moment, not because I don't know the answer, but because of how to phrase it in a way that doesn't raise unnecessary questions.

"…If he has to," I say finally, choosing the safest version of the truth. Ruri looks at me quietly, clearly processing every word, her expression thoughtful in a way that doesn't belong to someone her age.

"Then… Papa won't lose, right?" she asks, her voice soft but steady.

"He won't," I answer without hesitation.

"And in both cases," I continue, "he'll be fine," adding just enough certainty to settle any doubt before it forms. That isn't optimism or reassurance—it's simply fact, grounded in something I've already witnessed. I've seen what he can do. Or more accurately… I've only seen a fraction of what he can do, and even that was enough to leave an impression that doesn't fade. Three years ago, during the Demon King incident, the entire world watched something impossible happen without ever understanding it.

People called it a mystery, an unexplained phenomenon, an event where the invasion simply stopped without warning, without reason, and without a single name to credit. There was no explanation, no aftermath—just silence that swallowed everything that should have followed. I know better, because I was there—not at the center and not in the final moment, but close enough to feel it, and close enough to understand that whatever happened… wasn't something normal.

And the cause of it is the same person who spends his afternoons watching anime, complaining about paperwork, and almost cooking unknown eggs like it's a perfectly reasonable decision. I glance at Karin, then at Hikari, and finally at Ruri, letting that thought settle for a second before exhaling quietly. … Actually, that part makes more sense now. Ruri takes a small breath before smiling softly.

"Okay, Auntie," she says, her voice light but sincere. I blink when I hear it again—the word"Auntie" —and feel something shift slightly in my chest, something unfamiliar and unexpectedly warm, like a space I didn't know existed just… filled in without asking. I look away for a moment, giving myself a second before responding.

"…Yeah," I reply quietly. Karin leans back against me, completely relaxed now.

"Papa is strong," she says with absolute confidence, like it's the most obvious thing in the world.

"Very strong," Hikari adds sleepily, not even opening her eyes.

"He is," I agree without hesitation.

"Stronger than me," she adds, glancing up slightly.

"Definitely," I say, which earns me an immediate pout.

"For now," I add right after, and just like that, her expression shifts as she straightens slightly, clearly satisfied with that answer.

"Then I'll get stronger," Karin declares, clenching her fists with determination.

"Just… don't burn the house down while doing that," I reply dryly.

"No promises," she says.

"That was not the correct response," I mutter Hikari shifts in her sleep, mumbling something incoherent that sounds vaguely like food-related negotiation, which I choose not to question. I glance down at her briefly, then back at the screen, then around the apartment, letting my gaze move slowly as everything settles into place. This situation is still absurd, ridiculous, and completely unreasonable when I think about it properly, and yet… it isn't entirely unpleasant in a way I didn't expect. I exhale quietly.

"Nii-sama…" I mutter under my breath, a hint of disbelief still lingering. Of all the ridiculous things you could have done, you somehow managed to do this—and somehow, against all logic, it works. I shake my head slightly and lean back into the couch as the anime continues playing in the background, letting the noise fill the silence just enough. Still, if there's one person who can deal with whatever is happening in that dungeon—one person who can fix something that shouldn't even exist—then it's him.

Even if he doesn't fully understand what he's capable of, even if he never acknowledges it, and even if he insists on acting like he's just… normal. I close my eyes briefly, then open them again, because I know better. He's not normal, he never was, and he probably never will be.

End of Chapter 12 RETIREMENT STATUS REPORT Owner: Ren Arclight Former Occupation: Demon King Slayer / World-Saving Archmage Current Occupation: Investigator of Reality Malfunctions Peaceful Life Goal: Stay home, avoid danger, and maintain a stable, low-expense life.

Today's Activities: *Delegated childcare to A-rank sister *Exited apartment with minimal casualties *Performed unauthorized spatial warp (efficient) *Entered sealed C-rank dungeon alone *Detected abnormal dungeon silence *Confirmed absence of monster activity *Identified complete ecosystem suppression *Located boss room with no battle traces *Confirmed missing dungeon core *Detected concealed structure beyond system layer *Destroyed environmental obstruction (throne) *Triggered hidden anomaly exposure New Developments: *Dungeon operating without core (system violation) *Boss defeat recorded without structural completion *Environment shows signs of artificial suppression *Hidden layer detected beyond standard dungeon design *Unknown entity or force interfering with dungeon mechanics *Anomaly classified as non-natural occurrence Household Status: Supervisor: Ruruka Arclight (High Reliability) Children Status: *Karin – Emotionally stable (pending next trigger) *Ruri – Maintaining order (critical role) *Hikari – Asleep (temporary peace buff) Peaceful Retirement Stability: 100% Before Doorbell 0% Dragons Hatched –9000% Financial Stability –30000% Dungeon Exposure –60000% Guild Involvement –100000% Dungeon Destruction –150000% Family Awareness –200000% Anomaly Encounter –300000% Reality Integrity Questioned Current Retirement Status: Irreversibly Compromised Immediate Consequences: *Direct encounter with unknown dungeon anomaly *Potential system-level threat exposure *Risk of escalation beyond rank classification *Possibility of external entity involvement Operational Assessment: Mission Status: Ongoing Situation Type: Unknown / Unregistered Threat Level: Undefined Emotional Status: Calm - Suspicion - Focused Concern Future Outlook: Rapid Escalation Likely Archmage Personal Statement:"I was supposed to just check it."

Reality's Response:"You found something worse."