Chapter 161: Physics Negation (Immunity)

Four-dimensional technology is already difficult in itself, but as I delved deeper into the field, its scope kept expanding, and understanding it became increasingly hard.

I could grasp it from a fabrication standpoint.

A mathematician could understand it through theory.

But Hiyori—who was neither an engineer nor a mathematician—struggled to keep up.

We sat facing the “Divine-Disappearing Staff,” pressing our foreheads together as we tried to align our understanding.

I explained while folding a square sheet of origami paper in front of her.

“Listen. You take this square sheet and fold it so its area becomes one-quarter. First, like this—just a normal four-fold. You get that, right?”

“Yeah.”

“Now another pattern. Like this. It’s the same intermediate step as folding a crane.”

“Yeah.”

“These two folds are different processes, but from a top-down 2D perspective, they’re both just one-quarter area. You can’t distinguish them in two dimensions. But when you unfold them, they open in completely different ways. They’re different in three-dimensional structure. The same thing happens when you extend folding into 3D and 4D.”

“Hmm…”

Hiyori turned the two folded papers in her hands for a while, thinking, then nodded.

“So when you store Kyanos in four-dimensional space and it just disappears, even though it’s the same ‘disappearance,’ there are different methods of doing it?”

“Exactly. And that connects to stability. For example, Hatobato’s four-dimensional folding is like this. And the Spirit-Disappearing Staff’s folding is like this.”

Hatobato’s method forces a complex folding pattern all at once.

The staff’s method, on the other hand, is simple—but repeats simple folding over and over again. Fold once into quarters, then fold that into quarters again, and again, and again.

“So Hatobato’s method does something complex in one go. The staff does something simple repeatedly. If you keep folding a sheet like that, it gets smaller and smaller, harder and harder to fold further, right? In theory you want to keep folding indefinitely, but the staff’s original shape isn’t a perfect square, and the folding is sloppy, so it starts to distort halfway through—that’s the image.”

“I remember that thing about folding paper 42 times reaching the moon. Even simple actions become absurd when repeated.”

“Yeah, exponential growth. In four-dimensional tech, instead of increasing thickness in 3D space, it folds through dimensions. But some kind of ‘existence overlap value’ or ‘redundancy variable’ shows up only when four-dimensional math is involved.”

I don’t fully understand four-dimensional mathematics either. I only understand how to take the resulting geometric outputs and physically fabricate them.

And Hiyori, in her own way, was digesting four-dimensional theory through magic.

Staring between my folded paper and the faintly transparent, almost ghostlike staff, she muttered:

“…Is it doing recursive mana processing? I see. Then rather than mana disappearing or appearing, it’s actually just passing through four-dimensional space and becoming invisible… forming one continuous flow… circulating… and layering itself repeatedly… hm… if that’s the case, it’s constantly cycling so it doesn’t need storage… but then the loss rate… hmm…”

After analyzing it for a while, Hiyori returned from her own mental world and asked:

“So with the staff’s method, wouldn’t mana loss be way worse than Hatobato’s? And I don’t think it produces the same effect.”

“Oh? Nice. You’re reaching that conclusion from a mage’s perspective too?”

“I don’t know the first half of what you’re saying, but I agree with the second. It likely produces a different kind of four-dimensional effect than Hatobato’s system. Though… if we test it, it might be dangerous.”

“No. It’s actually far more stable than Hatobato’s method. If the recursive inter-dimensional mana loop is properly connected… in other words, if the fabrication precision is high enough, causing an accident would be difficult.”

Hiyori, acting as our safety supervisor, gave her approval.

That’s that, then.

If done properly, the Divine-Disappearing Staff’s method should be stable and not misfire. The system is simple, after all.

And even if it does misfire, it can be fixed. Because it’s simple.

A smartphone breaking is hard to repair.

But a string telephone is easy.

Compared to Hatobato’s advanced civilization technique, this Earth-origin, ground-up four-dimensional system is far simpler and more manageable.

Under Hiyori’s supervision, I began precision adjustments using a long pole with tools attached—like a high-reach cutter modified into a remote manipulator.

Approaching directly would risk getting caught in a dimensional accident and being flung into nowhere, so keeping distance was essential. Three meters of separation, yet still maintaining precision—that level of work is something only I can do. Human manipulator, indeed.

Still, working indirectly takes time.

It took three full days to finish the adjustment.

After three days of tuning, the uneven, unstable staff finally became sleek.

Nice… very nice… it’s like it went on a diet, reduced swelling, and got properly made up! Its original mathematical beauty is finally showing!

While I stood there smugly, Hiyori ran safety and functionality checks using mana control.

After about an hour, she gave the all-clear.

I rushed forward, rubbing my hands together, ready to embrace the staff that had dropped to the ground after deactivation.

“Ohh, so this is the real texture of the Divine-Disappearing Staff! It’s warmer than I expected. It’s absorbing sunlight heat? Well, it is metal. That makes sense. Alright, alright—now let’s test the function…”

“Wait. I’ll activate it. Give it to me.”

“Huh? Why?”

“It consumes absurd amounts of mana. If you activate it, you’ll run out instantly and pass out.”

“…That much?”

I’ve got around 140K mana, you know?

And she’s saying that’s not enough?

What a glutton of a staff.

When I handed over the upgraded Divine-Disappearing Staff, Hiyori casually activated it.

Immediately, both the staff and Hiyori—who was channeling mana into it—floated upward, becoming semi-transparent like a ghost.

“Oh… so that’s the proper activation state. Huh. What’s happening there?”

“Dairi, hit me.”

“Huh? Why would I do that? No. I’m not hitting you.”

“Ah… right. Thanks. No, I mean—throw something at me. Even a paper airplane.”

“That I can do.”

I folded a paper airplane from the origami I had in my pocket and threw it at her.

It passed straight through Hiyori and flew out the other side.

What?!

“What is that? An illusion? Where are you right now?”

“I’m right here. Not an illusion. I’m in a state like a ghost-type monster—physical immunity.”

“Physical immunity?!”

Hiyori smiled at my shock, then deactivated the staff and returned to normal, landing on the ground.

“…Phew.”

“So you were basically invincible just now?”

“Kind of. Though unlike natural ghost monsters, it consumes insane mana. That 30 seconds used about 5000K.”

“So… around 170K per second? That’s expensive. Or maybe cheap, considering it grants physical immunity?”

She handed the staff back, and I examined it closely again.

So that’s it.

Ghost-type monsters phase through physical objects because they were partially intersecting with four-dimensional space. The mystery was solved from an unexpected angle.

“If ghosts can maintain physical immunity as a passive state, then logically the activation cost should be reducible further, right?”

“Yeah. Also, I think the Demon King’s physical immunity is an upgraded version of the same line as ghost-type magical creatures. Now that I’ve experienced physical immunity myself, I get it—it has that same unsettling sensation as attacks simply not working.”

“So basically, Divine-Disappearing Staff is Physical Immunity Level 1.”

This is insanely interesting.

I never expected we could reproduce a ghost-type passive skill in this form.

Isn’t this basically a must-install feature for the staff?

I can even activate it myself for a split second—maybe 0.5 seconds at most. And even half a second of physical immunity could save a life. It would probably end up being used as a precise timing-based dodge, like a perfectly-timed evasion against incoming attacks.

…No, wait.

If it truly puts you into a ghost-like state, then there’s a chance it becomes vulnerable to exorcism magic.

If exorcism magic isn’t actually “blasting ghosts,” but instead “blasting anything that partially intersects with four-dimensional space,” then physical immunity mode could backfire completely.

If that’s the case, I’d need to increase the folding iterations even more, strengthen the existence overlap density, and pull it back toward a more stable three-dimensional configuration… but then mana consumption would spike again. Which means reducing base cost becomes the priority, and in that case…

Questions kept piling up.

Ideas kept piling up.

This is getting fun.

Nice. Physical immunity. Interesting. Very interesting.

I absolutely want to refine and elevate this further and incorporate it into Kyunos.

Four days remain until the one-week deadline Hiyori and I set.

In those four days, I’ll dig deeper into this technology—and turn it into fuel for forging the ultimate, invincible staff: Kyanos.