Steel Trim
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Engineering, Magic, and Kitsune Ch. 59
🕑 Added 2025-12-17 02:38:33 +0000 UTCJohn's breath caught, and his hand trembled as he stared down at the ofuda. It couldn't be. No, there had to be something off, but several pieces fell into place all at once.
Ofuda and similar items could only be created by mortals; the process didn't work for Unbound or yokai, hence the niche of the priests. In the same way, he had to avoid magical contamination while he was making them.
Both channelled magic through an input, producing effects by shaping it. The damned thing was so familiar because it was a two-dimensional magical array, using the characters themselves as a medium. A couple of brief scans with his detector confirmed that the paper itself was doing nothing. Strangely, paper shouldn't provide any sort of magic nullifying effect in keeping the energy flowing through the proper pathways. How did it function?
Perhaps the ink itself worked well enough for that. It was like a bizarre inverse of what John did to make his own tools. Where he used crystalline constructs to contain the energy, the ink seemed to… attract it, perhaps? No, that didn't seem right. He would have to test it to see what it was actually doing. Maybe the ink was just far more conductive to magical energies than air, allowing it to maintain enough energy for the effect to take place, even as the rest bled out.
Though that was almost beside the point, John's foci and the charms of the priests worked on the same principles!
That meant there would be a design overlap; he could learn from their works rather than having to put everything together himself!
This could be the key to cracking compound magic by giving him examples of artifacts that use them, all of which work outside a living creature! There was a chance that John could make a yokai-repelling focus that would affect everyone but Yuki and Rin. Hell, maybe he'd be able to figure out more esoteric effects, too.
"Lord Hall, are you alright?"
He jolted, snapping to Takuto, who leaned back with wide eyes, almost falling out of his chair.
"I—My apologies, Lord Hall. I didn't mean to interrupt you, but you've been staring at it for a while," he soothed. "I hope my poor brushwork didn't offend you."
John breathed in.
And out.
His heart didn't slow, and a smile split his face, despite all his efforts to hide it.
"It's fine," he laughed out, quickly standing up, and pulling a knife from his pocket. "I'll be back in a second, just sit tight, alright? Don't leave the room, and please try to make any other charm you remember." Hurriedly, he cut the ofuda free from the sheet as Takuto tried to lean even further back. With his prize, he ran from the room like a child dismissed from school at the end of the day, rushing towards the bathing room.
"Yuki, Yuki!" he called, frantically knocking on the door, an edge of excitement clear in his voice. "I didn't know. How didn't I know? This is so, so big!" he giggled like a deranged lunatic.
"One second, please," she responded, and he heard the kitsune rise from the water. Outside the door, he frantically paced as ideas came to him one by one. There was so, so much that he could do! He had to get into the workshop and figure out exactly how these things worked. Maybe leaking was part of their functionality? If the half-processed energy that would drip out of the ink partway through were core to the functionality, that would mean he could tap into a whole new field of possibilities!
Despite looking simple, the charm was meant to repel spirits, so presumably it tapped into some complex prebuilt weaknesses built into them. After all, if it were something simple, it could be triggered accidentally, and the fact that it repelled vermin as well was curious. Was the weakness also built into them, or did it function on different principles there? There were so, so many questions, and he couldn't wait to get to testing.
"It's all the same, Yuki," he rambled as the kitsune presumably dried herself off, a flash of light and heat washing out from under the door. "I don't know why I didn't suspect it before. Of course there were underlying mechanics that the charms the priests make. Why did I ever think it would be entirely arbitrary?"
The door slid open, and a mildly fluffier-than-usual Yuki stepped through, smelling of lavender, which was strange given he certainly didn't have any lavender soap, towering over him as she watched him with a curious eye. "I expected to have a bit more time to soak before you came over," she calmly commented. "You must have learned something rather interesting watching the priest make an ofuda."
John quickly nodded, holding the talisman up to Yuki to examine.
Gently, she took it from his hand, reading the text with a furrowed brow as if it were some dense philosophical treatise. "This is a blessing to keep pests like akaname and rats from a household while the owner is away," she stated. "I don't see how it's so special."
"See this at the top?" he asked, tapping the aforementioned section. "It's familiar. Very familiar. It's almost like an inverse of what I did with the filter that makes sure only earth-aligned magic goes into the correct capacitor on my early gauntlet designs."
The kitsune's pupils widened as she beheld it with a new reverence. "I was never a great scholar of priestly matters… at least to my memory, but what does that mean to you?" she asked.
"This might be the key to everything!" he rambled, starting to pace. "You've surely noticed that all my creations use the most 'basic' forms of magic, yeah? I doubt that something as complex as a barrier with an allow list uses only those; it's my chance to figure out how to use something more complicated and move into esoteric magics! Even if that's out of the cards, that means there's a millennia of practices and knowledge that I can draw on, once I get examples to pick apart!"
Yuki's gaze intensified to the point where it almost looked like she was trying to burn a hole through the paper. "Do you think you could turn a repelling ofuda into a focus? With only Rin and I allowed to exist within its confines unimpeded, we could run roughshod over a great many things."
"Maybe, I thought of the same thing," John stated. "I'll need a proper example, then I'll have to work on it. It might depend on how content Kiku is to sit back and try to play around us, but I'm not sure we have that time. Fighting the Nameless in the winter seems like a nightmare, and the village will be suffering badly by then, even if we subvert the defences to work with us rather than against us."
His grin twisted into something harsher, more vicious. "But I can certainly think of a weakness or two a static setup based on my filter system would have," he continued, ideas dancing in his mind. "Quick quiz, Yuki, how does this differ from a focus slotted into my gauntlet?"
A sly grin flickered onto Yuki's face as she looked him up and down, batting her eyes and flipping her hair. "Oh? Does the wise and mighty John have a lesson for me? I thought you had forgotten all about teaching me after you got your new, younger student," the kitsune teased, faux pain in her voice as she put a hand over her heart.
The man snorted, shaking his head at the kitsune, a faint pink colouring his cheeks. The adrenaline high of a new discovery slowly left his system, his former excitement replaced by a steadier thrum as his brain ground to a screeching halt. "Yuki…" he complained, his tone perhaps a bit too high-pitched.
"I suppose I can guess," she soothed, the hand over her heart rising to instead tap a single finger on her lip as she thought it through. Yuki's eyes narrowed, and her smile widened as she wordlessly turned to stare down at the sheet, silence hanging in the air as the wise kitsune gathered her thoughts. "There are many things. An ofuda isn't portable and must be attached to a host structure to take effect. The effect can only slightly be modified after the charm is created, while your foci have little levers you can pull in real time. One of these ofuda operates continuously without oversight, at least until the environment and decay taint the charm, while your gauntlet requires active use. On top of all that, your foci can accomplish far more direct effects easily, while charms like this specialize in the slow and subtle."
Oh, she was so close; she could almost reach out and touch the answer!
"One of those things is very, very important for solving our current problems with locating the priest's little traps," John cheerily stated.
"It isn't that it isn't portable, at least not entirely, because that on its own doesn't reveal any inherent vulnerability more than a hidden guard tower. The rigidity is a possibility; if you locate one, you can locate them all through the same method, but that does not provide the answer by itself…" Trailing off, the kitsune fell deep into thought. Not for too long, perhaps for a minute, but it was longer than she usually took to come up with an answer for, well, anything. Suddenly, her eyes shot wide open, and she inhaled sharply.
"I see." Her words were quiet, her tone airy. "It's an effect that continually works, and it has no way to store power as your gauntlet does, so it has to be constantly drawing magic from somewhere to maintain it." Her eyes met his, warm as a summer sunrise. "Very nicely done," she praised.
He eagerly nodded, a broad smile splitting his face. "Right, so!" he called out, rubbing his hands together. "The difference is going to be marginal, but as it works, it's going to have to pull in power, and the magic detectors? They aren't purely binary—Uh, they aren't purely yes-no. If I were to point one at something like you, it'd respond more strongly than if I pointed it at Rin. I just have most of them connected to something a bit more yes-no right now. What that means is that I can make a device that can tell us which side has slightly less dense ambient magic…"
"Pointing us directly to the nearest thing consuming magic from the very air. If I were in a better shape, I could do something similar, but this is a clever workaround," Yuki hummed, something thoughtful lurking behind her eyes. "It won't be easy, you know. The difference between a talisman and the great tide of magic washing over the world will be fractions of a drop. You won't be able to search from your flying disc, either, and I would wager the emanations of power from either Rin or I holding onto whatever you make would throw it off entirely."
"Maybe not," John admitted, "but we only really have to find one, don't we? Then, we can make something more specialized with that example. I mean, I'm still going to rig a detector with the ofuda that our priest is making, but I doubt it's going to work now that I know how they actually work."
"Our priest?" Yuki mimicked, raising a curious brow as she stared him down. "Are you planning on adopting him, too?"
A full-body shiver wracked John at the thought, all the hairs on his arms going straight as goosebumps covered him. "Ugh. No. Never," John groaned. "The guy isn't the worst person I've dealt with, but that's not a high bar. He's still one of the local priests."
The throaty vulpine chuckle that came from Yuki was equal parts comforting and positively infuriating, especially when she added insult to injury by gently patting him on his head.
Having nothing nice to say, he said nothing at all, looking away with the most put-upon expression he could manage.
The hand trailed down to his shoulder, resting easily rather than mussing up his hair even further. Fuck, he could use a good soak after today, but it was still early in the morning. Maybe, if he hit a wall with his other projects tonight, he would set aside an hour to relax in a nice, hot bath.
"If you'd like, I could take over your duties and see to Takuto while you go to your workshop," Yuki offered easily.
John stiffened.
Well, he supposed he couldn't stay too mad at her.
"Thanks, Yuki!" he beamed, starting to scurry off outside, before pausing, and making a brief trip through the building to collect a few of the motion-magic detectors he had placed around the house first, although leaving the ones right by his room. To be honest, if anything got by all his external defences, Yosuke, Rin, and Yuki without raising any sort of alarm, he'd probably be pretty screwed anyhow, and he needed those right now for a more important project.
Ugh, if only he had some form of passive defences to draw on beyond just detection, something that would keep people out! Landmines were an obvious no-go, but could he figure out some sort of non-lethal trap around the perimeter?
Another project to add to his constantly growing backlog, he supposed. Here we thought getting dumped in another world would free him from crunch, but some things were universal, like taxes and petty spite.
Say, if—when the Nameless were dealt with, he probably should put a portion of their wealth aside for "back taxes" he may owe to hopefully less borderline demonic tax collectors. Perhaps Unbound got some sort of exemption due to the risks of collecting from them? John could only hope and pray for that, because the thought of trying to navigate whatever tax code this nation held threatened to give him conniptions.
He was getting sidetracked again.
With his materials collected, he hurried out the front door, ignoring the baffled stare from Takuto as he rushed past the room like a breeze through the trees, only stopping to take a glance at the sheet he was working on. It looked like he hadn't actually drawn any more ofuda yet. Drat, John would have loved more examples to take with him in case inspiration struck. "Oh, Yuki wanted to talk to you, bye!" he shouted on his way by, jogging over to his workshop, hurriedly unblocking the door, and going to work.
Alright, first off, he had a rough idea of how to make the tool he needed, but he needed to get the exact details for its implementation sorted out. It wouldn't be the most precise, but, honestly, it didn't have to be. Once they got close enough, he could bust out the magic detector, and that would be that.
Hmm, but what if the active deterrence field interfered with it? After all, it had to be putting out something over the entire area. He couldn't just rely on the local magic being background level; he'd probably get loads of false positives.
Idea!
He ran over to his storage jar for the very same insulating sap he used to seal his foci, grabbing a small sheet of metal along the way. Quickly popping the lid off the pottery, he ladled a tiny dollop of the gooey substance onto the sheet before rushing over to his open-air vacuum bench.
Flipping a series of switches on the underside, the workbench let out an ominous droning hum, and a pair of white lights flicked on. Neither were essential to the device's function. Of course, if something created an invisible field of suffocation, you damn well wanted to know when it was running before you leaned a bit too far forward and had your lungs depressurized.
From there, he put on the specialized, infused gloves to protect himself and gingerly placed the sap in the airless field, immediately removing every bit of air from the clear-ish substance. John smoothed the pliant sap into a thin sheet before taking his magi-welder and hitting it with a burst of order to forcibly crystallize it.
Unfortunately, it left the material terribly brittle, and it threatened to crack as he lifted it. It'd be no good for anything beyond laboratory use as is, sadly.
Thankfully, he had some leftover glass around! He wasn't sure what it was originally supposed to be, given that it was found broken on a cart tossed into the river, but shards worked just as well for his purposes. It was quick and easy to melt them down, too, which he then poured into a circular mould to make a slightly thicker circular sheet, although he still wouldn't want them to take a hit. With a steady hand, he trimmed the sap and transferred it from the metal to the glass, then placed another chunk of glass on top, sealed the sides with a thicker layer of the magic-repelling goop to prevent any magical energy from leaking in from the inside and bypassing the filter. All in all, the construct was perhaps half a centimetre thick.
He had plenty of time to think about the design for the… other device he needed to name while he worked on the following three lenses with varying thicknesses of sap between the glass plates.
The more complicated design work began.
In theory, all he had to do was compare two outputs, figure out which one was greater, and then put out energy only to the correct side. It was an easy problem under most circumstances, but the question was more about how to do it fast with the parts he had on hand. Making an electrical comparator would be ideal, but he certainly didn't have anything like that on hand.
The simple answer was something mechanically antagonistic, but he wasn't sure what he had that would work. Hmm. Maybe something with two pulleys fighting over a string? Eh, but then that'd run into issues if one side was "dominant" for too long, risking quickly burning out from strain or snapping the string, causing false readings.
…He was an idiot. He could just make a tiny wooden tube and throw an iron ball bearing in the middle. Slap a simple electromagnet made with a nail and some copper wire, fed by a detector, at either end of the tube, and the ball will be pulled towards whatever side is stronger, creating a simple switch once it can detect which side the ball is on.
That could be done with a simple pressure switch; he'd just have to attach a level to the top of the device, which he could "borrow" from one of his construction tools.
Yeah, yeah!
Then all he needed to do was find a way to rig the detectors to detect all around, which was honestly as simple as stripping the coating off them.
From there, he could stack a few rows of tubes into an asterisk shape, and he had a bona fide magic compass!
With a smile, he continued his work, quickly finishing up the sheets and beginning the main project itself.
Oh, they weren't going to know what hit them! He even had a few ideas about what to do once they found the ofuda. After all, the charms only activating once they were "rooted" was an interesting fact…
First, though, John had to finish his "Wizard Compass".
Comments
Trevyn Lane
John was accidentally discovering how to make ofuda over a decade, and refined them to the point that he can compete with most unbound and yokai in a straight fight. The irony is not lost on Yuki... and she finds it hilarious, I bet.
Lilim Lilim
No, it's not a cosmic restriction: unbound don't know they have to protect the Ofuda from their aura. Only reason John can't become unbound is because of his status as an ordinary human who has never made the Grand Deal, an event long in this world's history that blended human and yokai by... probably in the range of 5-10% for most, 50-70% for unbound. No Deal, no innate magic, no magic to unbind.
Lilim Lilim
I NEED to see a 'design' episode from Yuki's perspective someday, seeing John go from "traumatized gloomy foreign wizard" to "gnome on a caffiene high" has to be a treat
TACNUK3Z
The way that Yuki treats John as some halfway between that one scared streetcat you’re way too invested in and a precious little baby to pat and protect is very cute. Great dynamic.
K. William Klaassen
If only mortals can make Ofuda, and John's devices work like Ofuda, does that mean John can't become Unbound?
Venno Unthammer
I found myself reading this chapter faster and faster to keep up with the manic energy John wad oozing from his very being.
K
Heh. He's gaming again. Yuki is also doting on him and he doesn't even notice in his excitement. Thanks autocorrupt. Fixed.
