Chapter 60: Day 11 ④

I accompanied Illya and followed Rin into the room. I had been told to "provide support," but the most I could do was open and close the door for them.

Rin pulled out the desk chair and sat down, while Illya, prompted by Rin, sat daintily on the edge of the bed. Since I was there to support, I decided to sit beside Illya.

"Now then, to get straight to the point, what I want to ask Illya is about the 'method to restore a human who has been parasitized or possessed back to their original personality.' I’ve mastered most fundamental Magecraft knowledge, but this isn't my specialty. I figured you might be well-versed in it."

Rin waited for Illya and me to settle in before tossing out the question. Her tone was light, but her gaze was devoid of any insincerity. In response, Illya let her eyes wander as she entered deep thought.

"In terms of 'knowledge,' what I have isn't much different from what Rin knows. My Magecraft is the kind where, even without specific steps or formulas, if a result is possible, the 'logic' constructs itself to produce the outcome. However, I have actually performed such things before, so I might be able to tell you a few things."

"Please," Rin replied solemnly, leaning forward. Illya straightened her posture in response. As the atmosphere grew tense, I felt a lump form in my throat.

"...Very well. If you want to restore someone, the simplest way I know is to 'Exclude' the foreign substance that has mixed in. If that isn't possible, then you must 'Alter' the foreign substance itself. There is also... though it's difficult, having the original personality mentally overpower the new one."

"Tell me about those in as much detail as possible."

"Let's see. First, 'Exclusion.' This involves removing the core of the spiritual body that entered later directly from the physical body. Using Spiritual Surgery (Shinrei Shujutsu) or something similar to physically exclude it; as long as the 'insides' haven't been devoured, the person should return to normal. Second, 'Alteration.' This involves interfering with the core of the new personality's spiritual body from the outside, making it unusable as a vessel for consciousness. You can physically destroy it, or change its nature so the compatibility between the core and the new spirit shifts—or you could simply erase the dwelling spirit itself."

Illya raised one, then two fingers as she explained, before holding up a third.

"Third, 'Recurrence.' If you call out to the original personality and give them a will of equal strength to the new personality, an exchange of personas should occur. In this case, I don't know if the new personality will vanish. If it remains, it might cause some sort of lingering ill effect."

"...I see."

Since this almost perfectly aligned with the conversation I had with Lia last night, it was quite easy to digest.

If I were to use my own case as an example, 'Exclusion' would be removing the 'Sheath'—my core—from this body.

'Alteration' would be destroying the 'Sheath' or severing my connection to it. Or even just erasing my consciousness from within the 'Sheath.'

'Recurrence' would be awakening Lia's consciousness, which should be sleeping within this body, and pushing myself out. In that case, since the 'Sheath' would remain, it would be a fifty-fifty chance whether my consciousness would be devoured or not.

"Regardless of the method, what you must watch out for is the presence of the original personality. Even if the new personality vanishes, if the original has been extinguished or has lost the will to live, they will simply become a vegetable. Eventually, the body will die as well. And a potential concern is a 'double suicide' involving the physical body initiated by the new personality. To the person trying to get them back, the old personality is a hostage. It wouldn't be strange if the new personality has set up a 'Device' as a countermeasure. For instance, something where the body dies along with the extinction of the new spirit."

I had been mentally constructing a procedure to save Sakura based on the information provided, but those last words wiped it all away.

"Then... even if we devise a way to save Sakura, we can't recklessly make a move from our side?"

Several methods had been suggested, but that final point effectively blocked every path. And the opponent was a monster—a Magus who had lived for generations. It was hard to imagine he hadn't constructed a means of self-preservation.

"Yes, exactly, Alto. Just as you said, the moment things fell into this state, our loss was practically guaranteed. Since the girl named Sakura is already 'The Property of Makiri,' it’s only natural that trying to steal someone else's property carries nothing but risks, right?"

I almost raised my voice at Illya's words. I nearly reacted to her treating Sakura like an object, like "property." However, I stopped myself at the last second. I realized Rin was staring at me intently.

"Alto. Do you have any ideas? Anything with minimal risk and a high success rate?"

"N-no. Nothing that could be a deciding factor. Rin, do you—"

I turned to Rin as if clinging to hope, but she shook her head before I could finish, leaving me speechless. Rin opened her mouth slowly, as if exhaling her agony.

"With the means I have on hand, they're all much of a muchness. At worst, the 'Device' is an issue we can't even get to. Illya, what about you? You, who can reach the same result even if the steps are different."

"I can't even lay a hand on it. My Magecraft is for a different purpose to begin with. My current Magecraft is nothing more than a fragment of an incomplete Wish-Granting Machine."

A few words in Illya's response caught my attention, but I didn't have the luxury to worry about them now.

Was this a stalemate? At this rate, even if we stormed the Matou estate, we would have no choice but to strike down Matou Zouken while he wore Sakura’s face.

"...Let's review the conditions from the beginning. There might be a loophole somewhere that we've overlooked."

Rin said this, but looking at the situation, it was clearly desperate. Rin herself likely knew that. Her asking Illya was probably a last-ditch effort. She seemed disappointed, but it felt like it was within the range of what she had expected.

"If it's 'Exclusion,' that fake priest could perform Spiritual Surgery... no, there's little grounds for success, so I can't fully trust him. Then 'Alteration'? If Matou-kun's story is correct, the core is likely a Worm, but we’d have to identify the Thaumaturgical Foundation first. As for 'Recurrence,' we don't even know the trigger, and without grasping her mental state..."

"If the core of Makiri Zolgen is a Worm, Spiritual Surgery would be difficult."

"Then if we're betting our chips, it would have to be 'Alteration.' If we can analyze the host worm and eliminate it with pinpoint precision... No, that's no good. I don't know if we'll have the luxury to analyze it, and our intentions would be exposed the moment we tried. Besides, it's unthinkable that he hasn't planned countermeasures for a method this obvious. He's likely planted a dummy or set a trap triggered by that. Maybe a combination... Then, what about injecting Prana to temporarily jam his control? Given he’s participating in the War, I doubt he'd easily counter other sources of Prana. It would cause Sakura pain from magical resistance, but the burden shouldn't be too great. The problem is whether we can paralyze Zouken's consciousness inside. Even if it goes well—no, there's no follow-up. If a trap activates independently of the worms, I don't know if our response would be in time. Then, what about breaking the contract—likely a high-level Familiar contract—between the worms and Zouken? But to intervene in a Magus's contract, we lack the time, the skill, and the Prana. We just don't have that kind of time, do we?"

I could only watch as Rin scratched her head in frustration. I tried to think as well, but for every step forward, two or three more problems arose. Amidst Rin's constant muttering, she suddenly snapped her head up and looked at me.

"Alto, how was it for you last time? You didn't say anything about this problem, but was it resolved?"

"...No. To begin with, this specific problem never surfaced. It was likely a situation that could have happened there too, depending on the conditions. No... perhaps it was something that actually happened after that. Regardless, it is impossible for me to know now."

I met her challenging gaze head-on. For a while, we stared each other down, and when I didn't look away, Rin let out a sigh.

"I thought so. It's hard to imagine you intentionally withholding information. Let's change the angle then—among the weapons in that Golden King's collection, were there any swords or spears strong in this area?"

"No... within that collection, the only things that might be effective were a curse that delays the perceived time of the target, or something that induces paralysis. Both could be considered Noble Phantasms, but since their True Names cannot be released, the effects are short-lived and limited in scope."

"I see," Rin whispered, falling back into thought. She was likely tracing back her memories; judging by how her murmurs occasionally mentioned the Ryuudou Temple and Caster, her previous question was definitely about the events a few days ago.

"............Wait a minute. I was so focused on the 'last time' that I completely forgot. What did you do four days ago?"

She widened her eyes and stopped dead.

"Four days ago... you mean the incident with Rider's Bounded Field at the school? But why bring that up now?"

"Just answer. It’s necessary. At that time, the effect of the Bounded Field definitely weakened. I’ll ask again. Why were you late?"

I didn't know what she meant, but it was unusual for Rin to act this way. I cast aside all doubt and prepared the answer in my head.

"I was late because I attempted to dismantle the Bounded Field. However, in the end, I could only weaken it before rushing to the scene."

"How? No matter how much it was being supplemented by Prana, that thing was constructed with proper procedures. It wasn't something even I could handle."

"The Bounded Field itself was a Noble Phantasm, so there was nothing I could do. To dismantle it quickly through external interference is difficult. However, the Magical Formula drawing from the land was different. Once I realized that, I simply analyzed the school building and went around crushing the anchor points of the Magic Circles. As a result, it could no longer maintain the Prana required to stay active, and its scale shrank."

"What I want to know is the 'method you used to crush the anchors.' Even if the Magic Circles weren't Noble Phantasms, I—no, unless it’s a Magus on the level of Caster, there's no way to erase Magecraft linked to an activation in such a short time."

"Ah..."

Then, it finally occurred to me. The specialized Anti-Magecraft Noble Phantasm I used then. Was this the factor Rin was looking for?

"——Projection, Complete. Trace Off. Rule Breaker: All Spells Must Be Broken."

A lightning-shaped blade. A sinister color. What appeared in my hand was the Noble Phantasm of the Witch of Betrayal. At the sight of that familiar dagger, Rin's face stiffened.

"This is... Caster's...? Alto, you mean you can even Project the Noble Phantasms of other Heroic Spirits?!"

"It's not particularly restricted, but... uh, had I not mentioned it?"

"I didn't hear a word! I completely thought you could only Project things other than Noble Phantasms!!"

Looking back, I certainly don't remember talking about it, and during our previous talk about producing weapons, I had only shown harmless things.

As for Gilgamesh’s treasures, since I didn't call them Noble Phantasms myself, she likely thought they were just subordinates to them and thus projectable. But the treasures are indeed capable of being Noble Phantasms, their power no different from their legends. Containing mystery, those treasures are a world apart from ordinary weapons and, as said before, can be called Noble Phantasms.

"At any rate, this Noble Phantasm boasts unparalleled superiority in matters of Anti-Magecraft. Excluding other Noble Phantasms, anything related to Magecraft can be returned to its state before it was created—back into Prana."

"—How absurd. No, in this case, your Magecraft is even more absurd than the dagger. But with this, things have taken a slight—no, a massive turn for the better. Now we just have to worry about whether there are any extra traps..."

"............Hey, what is going on? Why can Alto use the same Magecraft as Onii-chan?"

...Both Rin and I must have been quite desperate. We lacked the composure to pay attention to our surroundings.

Despite Illya being right there, we had brought up the 'last time,' and I had even gone as far as chanting the Magecraft activation spell out loud instead of just thinking it. Having told Rin everything, my guard had simply dropped too far.

"...How do I put this? It's impossible. It's like two or three miraculous coincidences happened all at once. It's less like walking a tightrope and more like walking a thread."

In the end, we had no choice but to tell Illya everything. Illya's reaction after the story was something else. Her mouth was agape, her eyes wide. She stood motionless as if she had forgotten to breathe. And the words that finally came out were these:

"But, I've wondered about it for a while. Lia and Alto have different 'colors.' Even though the shapes are the same, Alto has more of a warm-toned color, I guess?"

I think she wasn't talking about physical appearance. I didn't quite grasp the details, but it seemed the seeds of doubt had already been planted in Illya's mind.

"Er, well, to be honest, I don't really know why I'm like this either. Lia and Rin know my true identity, so that's one thing, but I haven't told Shirou yet. It would be a big help if you could keep it a secret."

"Yeah. Okay. Hehe, but I never thought Alto was actually Onii-chan. ...Wait? Would that make you Onee-chan?"

"...Could you just stick with calling me Alto? There's already enough of 'Emiya Shirou' with just the Shirou of this world."

More than anything, I felt nothing but resistance to being called "Onee-chan." Since I'd somehow stopped feeling any strangeness about being treated as Lia’s younger sister, I might eventually get used to it if she called me that, but I'd rather pass on that kind of familiarity.

"...Alto, you really are distorted, aren't you?"

While I was struggling with the persona I hadn't used since last night, Illya was quietly staring at me.

"Eh? Did you say something, Illya?"

"No, nothing. More than that, it's actually kind of funny seeing you talk like Shirou in that form."

Mph. I had reverted my speech pattern because I thought it would be easier for her to understand.

"...I thought this would be faster for you to grasp. Since you understand now, I shall return to my usual manner."

As I switched back, I realized once again that this "Saber-like" way of speaking had started to feel more natural. At this point, the "male" speech pattern was more likely to slip up, which left me with complicated feelings.

"That's better. This Alto is easier for me to get used to."

"Even if you say 'this' one, I am the same person regardless."

"Well, I can see where Illya is coming from. Along with the speech, there's an illusion that even the atmosphere around you changes."

Rin’s expression had lost some of its edge. It was likely because a path to rescuing Sakura—however small—had finally appeared. I, too, felt my spirits rising compared to the pitch-black darkness of a moment ago.

"Now then, that's enough small talk. Let’s finalize the plan, including the raid on the Matou estate."

Receiving Rin’s energized words, I looked her straight in the eye and nodded.