Caster's Factory

Carl quickly grasped the matter of Assassin's informants.

No, rather, she had found inspiration in the manga Tsukahara Meiji had brought over.

Assassin was a Ninja. There was no doubt about that.

Yet as an important part of Japanese culture, how could a country that valued cultural exports so highly possibly overlook it? Carl had suffered a setback from ninjutsu due to her lack of understanding of Japanese culture, so naturally, she had to investigate it thoroughly. However, there were simply too many varieties of ninjutsu, making them far too troublesome to deal with.

But while flipping through the materials—manga—she had inadvertently confirmed a plot point that let her deduce Assassin's identity.

Let's go through the questions one by one.

Assassin's informants.

Were dogs.

The legendary Ninja Dogs.

When it came to Ninja, the two most famous schools were Iga Style and Koga Style.

And among them... Iga Style Ninja possessed the strange ninjutsu known as the Ninja Dog technique.

Though rather than ninjutsu, calling it animal-training techniques might have been more appropriate. It was said that experienced Ninja Dogs could behave with intelligence no different from humans. They could also take advantage of their animal appearances to easily accomplish many tasks humans could not, which was truly terrifying and made one question the value of one's own existence.

Incidentally, Carl did not know whether Koga Style Ninja had Ninja Dog techniques, but it was commonly acknowledged that Koga Style Ninja had a particular fondness for cats. It was hard to imagine a cat lover using dog-driving ninjutsu...

Thinking back on it, Carl and Tsukahara Meiji had heard dogs barking from the moment they got off the plane.

That was obviously strange. Why would there be dogs in a sealed environment like an airport?

After that, too, the two of them could hear dogs barking almost everywhere they went.

Now that she thought about it, what if the barking was treated as a "signal"?

Like ancient beacon towers: once A spotted the target, it would bark into the distance. Upon hearing it, B would immediately bark as well, and then C and D, who heard B... In this way, information about the enemy could spread rapidly.

And dogs were humanity's friends. Many people kept dogs in the city, and with dogs mingling among humans, a few barks might seem irritating and noisy, but they would not feel "strange."

So... he had used this method.

If the Party Secretary's own son had been injured, and managing stray dogs was itself a benevolent act, then pushing it through would naturally be a matter of course.

That way, every dog out on the streets would at least need a leash. Any dog seen without one should be the enemy's Ninja Dog. It was equivalent to exposing the enemy's informants.

Once a spy was identified as a spy, it no longer had any value.

With that in mind, Carl pushed her sensory magecraft to maximum efficiency, ensuring that no one was watching her. After taking several twists and turns through side streets, she slipped back into the shadows.

If... it really was an Iga Style Ninja...

According to Tsukahara Meiji, Ninja culture was widespread, but only three Ninja were truly famous enough to be called gods of Ninja: Hattori Hanzo, Sarutobi Sasuke, and Fuma Kotaro.

Yet of the three, only Hattori Hanzo belonged to Iga Style. The other two belonged to Koga Style—which was said to use cats as Ninja beasts... Of course, Tsukahara Meiji had learned that from manga, so Carl was not about to believe it.

Then... Assassin's identity could probably be narrowed down to those three.

They were all exceptionally capable Ninja.

In the Holy Grail War, one of the worst obstacles was probably an outstanding Assassin.

Especially for Masters like Carl and Tsukahara Meiji, who could not be considered particularly capable, an ambush by Assassin would likely leave them only one path: death.

For now, she could only do everything possible to ensure she would not be tracked.

Thinking so, Carl repeatedly confirmed that no one was following her before yanking open an iron door and vanishing into the pitch-black space beyond it.

This was a factory.

Strictly speaking, it was an automobile maintenance factory, a place for maintaining and replacing parts on civilization's steeds—cars. The more civilized a city was, the more people liked to use high technology instead of walking. Wherever there were cars, there would definitely be automobile maintenance factories.

Otherwise, were people supposed to repair their cars themselves whenever something went wrong? That was obviously unrealistic.

What was Carl doing here?

Breathing in the heavy, mixed scents of various engine oils and metal components, Carl moved through a maze of massive machines. Since this was not along the main route, the only light came from the faint illumination filtering in from the space ahead. It was very dark.

Carl deliberately kept anyone from noticing her as she made her way toward her destination.

It was a warehouse.

With Da Vinci's help, Carl had constructed a small concealment spell here, hiding the warehouse from everyone's sight. And Da Vinci was inside.

The elderly man, his hair and beard completely white, wore a shirt casually draped over his body and trousers below. His thin arms were exposed to the air.

Around him stood machines of unknown purpose, gleaming with cold metallic light. In the corner was a bed crudely assembled from steel pipes. Within this space utterly lacking the style of a Magus, this Caster stood out completely as he examined something in his hand.

These machines, so clearly steeped in the aura of science, had been assembled by Da Vinci himself. In just over an hour, the brilliant scholar had greedily absorbed the knowledge called magical energy from Carl and built himself a Magic Workshop. Or rather, a magic factory.

With this automobile maintenance factory as cover, ordering all manner of mechanical parts would not seem too conspicuous. And when necessary, parts could be taken directly from other machines and fitted into equipment.

"Oh, Master. Welcome to my factory."

The elderly scholar raised his head from his research. Beneath his snow-white hair was an alert, energetic expression. He gave a slight bow to welcome his Master.

"Mm. So, have you made any progress?"

Carl did not stand on ceremony. She casually sat on Da Vinci's bedframe and asked without much expectation.

This had been Da Vinci's proposal, his plan for how to put himself to use in the Holy Grail War.

Whether as a Heroic Spirit or a Magus, Da Vinci was among the worst.

But there were also things only Da Vinci could do.

That was "learning."

This was not self-praise. The name Da Vinci was synonymous with a polymath throughout history. Yes, not a genius, but a polymath. This exceptional ability to learn was his sole Noble Phantasm worth boasting about.

Therefore...

"Yes, there has been progress. This is prepared for you, and that one is for Archer."

As he spoke, the white-bearded old man pointed to a rifle leaning against the wall. Then, like a child, he mischievously produced a pair of gauntlets from beneath his shaggy beard. It was clear that compared to Archer's weapon, these gauntlets were the product he was truly proud of. Like a salesman, he stepped closer with a researcher's enthusiasm and raised the gauntlets for Carl to see more clearly.

They were weapons specially tailored to fit Carl's bones. Their clean, streamlined form carried the savage air unique to striking weapons. Carl imagined it for a moment; without exaggeration, taking a punch from these things on the bridge of the nose would lead to far more than mere pain.

"I tried optimizing the magecraft formulae inside, then incorporated modern electrical science into them. These gauntlets are powered by both science and magecraft. Master, you are the type who prefers close combat over magecraft battles, aren't you?"

Listening to Da Vinci's calm voice, Carl felt as though one massive bomb after another had exploded beside her ears.

(He fused magecraft and science?)

(Hey, hey, is my Servant really okay?)

(Did his brain short-circuit from having too little magical energy?)

(This feels like an ice cream hot pot—one freezing cold, the other scorching hot... They simply can't be compatible.)

(And even if it could be done, he actually did it in less than one night?!)

(Could it be...)

Carl stared at her Servant in disbelief. Carl, known for her composure, had experienced two drastic emotional swings in a single night. In her sea-blue eyes, a tidal wave called disbelief had practically formed a whirlpool...

(Could it be that I actually obtained an incredibly powerful Heroic Spirit?)

Incidentally, ice cream hot pots really did exist in the world. Carl simply had never tried one.