17 The final enemy, the impregnable guardian

[Shirou POV]

"...Hey Tohsaka, is it really hopeless?"

"You, take a good look at your condition and think about it. It's impossible. It's out of the question."

"It would be a problem if you did something reckless again."

I guess it's really hopeless. We defeated Berserker. But, the cost was great. My body is no longer in a state to participate in the next battle. Right arm broken, multiple lacerations, and the toll of the past few days of overexertion...

Tohsaka and Luvia have given me a notice of removal from combat strength, or rather, a prohibition on combat. Furthermore, with tearful Illya and Miyu joining in, I had no choice but to restrain myself. Now, I'm lying in bed.

"I've also pressed the housekeeper, so give up."

"Not only the physical damage, but you also have to rest your magic circuits, right?"

"Onii-chan, Miyu and I will defeat the last enemy, so you really have to stay still."

"You must stay absolutely quiet."

"Okay, okay! I got it! Everyone doesn't have to tell me, I understand, so give me a break."

Tohsaka and Luvia's treatment was naturally carried out, but it can no longer fully heal me, and I had a proper treatment at the hospital this morning. The bone was healed with magic, but it is also immobilized with a cast for the time being.

I can't move even if I want to. Archer's card was taken away, and I was immobilized in bed with restraints. I thought there was no need to go this far, but I was glared at by everyone, including Sella, and my objections were completely silenced.

I don't know what kind of enemy the last one is, and I am anxious... well, we agreed that there probably isn't anyone stronger than that Berserker. According to the group of magic specialists, that was quite an extraordinary case.

"It should have been a very famous heroic spirit. The only thing I can say is that it was unfortunate to have to fight such a thing."

"Heroic spirits with such a high spiritual level are few and far between. Therefore..."

"So, we won't have to fight anything like that anymore?"

"Probably not. I can't guarantee it completely. If something unbeatable appears, we'll retreat immediately."

I see. That's reassuring. Tohsaka and Luvia are also with them. Illya and Miyu seem to have become quite friendly after yesterday's incident. If the two of them combine their power, they'll surely be fine.

"Well then, we'll be going now. We have to prepare for tonight's battle."

"Indeed. Emiya Shirou, take care."

Sapphire:『Miyu-sama, I want to talk to Shirou-sama alone for a bit, so I'll stay here.』

"Sapphire? ...Okay."

Tohsaka and the others left, and Miyu, who was about to leave last, was told such a thing by Sapphire. Miyu looked a little puzzled, but she didn't pursue it and just left. Only the two of us remained in the room.

"...What do you want to talk about, Sapphire?"

Sapphire:『Yes, I have a little question. I thought I'd ask Shirou-sama about it.』

"A question?"

Sapphire:『First of all, who is the Archer heroic spirit that Shirou-sama uses?』

"...To be honest Sapphire, even myself Dunno about archer true Identity, I'd like to know that myself."

Who is he? There's no way I can know that. He and I only have the barest connection. I got a little closer to him yesterday, but that's only because he got closer to me. I can't do the reverse.

Sapphire:『Who is this heroic spirit who uses such a True magic as a [Reality Marble], and has many types of Noble Phantasms swords and is very strong as well as having the ability to unique each Noble Phantasms sword he owns?』

"..."

Sapphire:『Yesterday, Shirou-sama used a Noble Phantasm called [Phantasmal Greatsword, Felling of the Sky Demon Balmung]. That is said to be the sword of the hero Siegfried, the Dragonslayer. However, he is not Siegfried.』

"Why are you so certain?"

Sapphire:『If he were Siegfried, there's no explanation for his ability to use such a True magic as a Reality Marble. Most importantly, he lacks the greatest characteristic of the hero Siegfried: immortality.』

"Due to bathing in dragon's blood, right? If I remember correctly, his only weakness was his back?"

Sapphire:『Yes. So, that Noble Phantasm is not the real thing. Considering our battles so far, it seems to be a replica produced by projection. That is to say, all those myriad sword Noble Phantasms are fakes.』

"... Fakes."

Sapphire:『also more surprising about the blue and silver holy swords that shirou-sama project is very powerful in the last attack defeating the berserker, I did not expect heroic spirit archer to have Noble Phantasms like that and even he was able to unleash the power of the blue and silver holy swords just like that. Shirou-sama if the holy sword is used outside of the dimension it is capable of destroying a city of fuyuki in my estimation, the energy produced by the holy sword is very abundant and powerful.』

Sapphire's assertion is likely correct. I don't fully understand, but I did realize they were imitations based on the real things. That's why I couldn't recreate that Blue and silver holy sword. In that case, he...

Sapphire:『I'm very curious about his true name. His ability is, in a sense, exceptional. Even though they are fakes, he can reproduce up to the true name of Noble Phantasms he copies and unleash of Noble Phantasms true ability like nothing. He has also managed to kill that Berserker multiple times.』

"Is that all you wanted to ask?"

Sapphire:『No. In a way, this is the main issue. It goes without saying that the heroic spirit of that Archer is a unique entity, but to me, you, Shirou-sama, appear to be an even more extraordinary being. It has been on my mind.』

What is Sapphire trying to say? Is it about my transformation using that card? But that's...

"The heroic spirit transformation is probably because he... he's lending me his power..."

Sapphire:『That's not it. No, I am curious about that too... but what I find most peculiar is regarding your magical energy.』

"About my magical energy?"

Sapphire:『Yes. Shirou-sama, you have fought many times. shirou-sama have continually consumed a considerable amount of magical energy day after day. Despite this, shirou-sama magical energy decreases and a few hours later shirou-sama magical energy charges rapidly as if someone is supplying magical energy to shirou-sama, It's as if... just like us Kaleidosticks...』

Even after hearing this, I, a novice in magic, do not understand what she's talking about. Is it really that peculiar?

Sapphire:『It's strange. It really feels as if you're being supplied with an infinite amount of magical energy from somewhere.』

Sapphire's serious voice alone echoed in my mind. Indeed, it might be a little eerie...

.........…

[Illya POV]

"The final enemy is here?"

"Yes, there's no doubt."

How many times has it been? We gathered at midnight. This is the gate of Ryudou Temple, the house of one of my brother's friends, Ryudou Issei. Considering the time, I don't think we'll be found by the people in the house...

"So, we don't know what kind of opponent we're up against?"

"We don't have any specific details. All I've heard is that it feels a bit different from the other Servants."

"Huh."

That might be a bit scary. But Miyu is here, so it should be fine. After the battle with Berserker, Miyu and I have become true friends. With Miyu by my side, I had a sense of security that we could defeat any enemy.

Ruby:『Hmm, this Mirror World is different from the previous ones, isn't it?』

"The card inside may be influencing it. Sapphire, analyze it."

Sapphire:『Understood. I will begin spatial analysis. Please wait a moment... What is this?』

"What's the matter, Sapphire?"

Just as I was thinking, Ruby and the others started discussing something. It seems this Mirror World is somehow different from the previous battles. Sapphire, who had been analyzing it, let out a puzzled voice.

Sapphire:『...I can't quite understand. For some reason, this space is strangely stable. It feels as if it's turning into something else. It's like a large barrier... no, it would be better to say a fortress.』

"What's that?"

Sapphire:『It's like it's trapping something inside and protecting it... once we enter, we may not be able to leave. Probably, if we defeat the heroic spirit inside, it will return to a normal Mirror World, but...』

"Can we get in?"

Sapphire:『I think that should be fine. This fortress doesn't seem to be repelling outside intrusion.』

"That's strange. Normally, a fortress is meant to repel outsiders."

Indeed. I understand what Rin-san is saying. Why is it like that? Since we can't figure it out, we decided to jump into the Mirror World for now. It seems we might not be able to get out.

Sapphire & Ruby:『Dimensional reflection pathway formation, Mirror World Corridor, partial inversion! [Boundary Jump]!』

.........…

"...What, is this...?"

We who had jumped into the Mirror World stood stupefied. It was clearly different from the Mirror World we knew before. The previous Mirror World had been an expanse of scenery identical to the original space. But this, this was completely different.

"...A castle?"

"This can't be... What is this..."

Before us was a huge white castle. Unbelievably vast. And large. The mountain gate of Ryuhodo Temple had disappeared, replaced by a huge castle gate. And the temple that was beyond the gate had become a castle.

Ruby:『It's likely due to the effects of that guy's Noble Phantasm,』 Ruby theorized.

At Ruby's words, we saw it. The silhouette of a person standing in front of the gate. Cloaked in armor, holding a large shield in his hand. A Heroic Spirit, holding a large cross-shaped shield, was standing there. The figure was unmistakably, a gatekeeper.

"A darkened Heroic Spirit. No mistake, he's the enemy."

"A shield, you say? I understand why it feels different now. Not attack, but a power of protection."

Sapphire:『In other words, would it be appropriate to call him a Shielder?』

Though he had a sword at his waist, what caught the eye was the gigantic shield. The name given by Sapphire was indeed apt. But it was somehow different from the previous darkened Heroic Spirits. After all, he didn't charge at us.

"He's not moving."

"I think he's probably guarding that gate. I bet he'll attack if we try to cross it."

"I see... I understand why from what was said earlier. His role is to repel intruders from the outside, not the space itself. He prevents those who have entered from leaving, so that the same foreign enemy doesn't enter twice."

Ruby:『So that's it. The space is a catalyst for creating that castle.』

Ruby:『Is that castle really so important?』

This entire space is being used to create that castle. And he is acting as a shield to protect it all. The fact that he went so far to create that castle certainly suggests this.

I guess what Ruby is saying is right. That determination strongly struck my heart. That means, that castle is something he wants to protect even without reason. It's just like how my older brother is to me.

"Either way, we can't get out of here unless we beat him, so we have no choice but to fight!"

"Let's do this!"

We all charge. Sensing our intent, the enemy raises his large shield, ready to intercept. The enemy doesn't move from in front of the gate. We all launch an all-out attack on the immobile enemy.

"Fire Cannon!"

"Shoot Cannon!"

"Five-Row Wind Bullet!"

"Seven-Row Explosion Bullet!"

A rush of magical bullets towards the enemy. Against our all-out attack, the enemy raises his shield to defend. At the moment of impact, a huge explosion occurs, and smoke rises. Eh, is it over? I thought so. But...

"No, you're kidding!? Unscathed!?"

"It was supposed to be an A-rank attack..."

Ruby:『This is amazing. He's not just holding a big shield for show.』

Sapphire:『Analysis complete. It appears that the enemy is doing the same thing as that Saber. However, his defensive power is far greater than Saber's magic output. While Saber used most of his magic for attack, he seems to be using all of it for defense. Perhaps a barrier field of magic?』

So, it's incredibly tough. How are we supposed to beat it? As I thought this, the enemy charged towards us. It seems that he got into his attack range.

"Waaah!?"

"Ilya!"

I wondered how he would attack, and he swung his large shield at me. I block it with Ruby, but his power is stronger. I was blown back, flying backwards. It, hurts. It's subtly painful.

Ruby:『He's got a good strength. An attack power that just penetrates physical protection. Ah, Miss Ilya. You've got a big bump on your head. Pukuku... You're tearing up. How funny is this.』

"Ruby, be quiet! It's coming back!"

"I won't let it."

Ruby is as usual. As we engage in our usual comedy-like exchange, the enemy swings his large shield and attacks again. That attack is intercepted by Miyu who appears from the side with a magic cannon.

But, even that surprise attack from the side, he skillfully moves his shield and deflects it. The magic cannon shot by Miyu bounces back towards Miyu. Miyu somehow avoids it, but our attack is blocked.

"Damn, this guy is more troublesome than I thought. Reflecting attacks with a magic barrier."

"If it comes to this, Miyu! Use the Noble Phantasm. If it's the Lancer card, he shouldn't be able to defend."

"Understood."

Following Luvia's instructions, Miyu nodded and pulled out the Lancer card. Then Rin's instructions flew at us. We create an opening for Miyu's attack. I nodded at the instruction and approached the enemy.

"Mid-level... Scatter Shot!"

I continuously released Scatter Shots. With this, it should be fine even if it's deflected. The enemy once again raises his shield to defend the scatter shot, but we succeeded in stopping him. Miyu took that chance, approached from behind with the cursed spear at the ready.

"Gae Bolg, the Spear that Strikes Death!"

I was convinced it had worked. I'm sure Rin and Luvia must have thought so too. But...

"Huh...?"

Miyu's dumbfounded voice reached my ears.

.........…

[Miyu POV]

What was that sensation? I stopped after releasing Gae Bolg. The sensation was different from when I fought against Caster last time. An impossible miss with this spear. What on earth was this?

Sapphire:『Miyu-sama!』

"Eh...ahh!"

Sapphire's cry. The moment I reacted to it, my head was smacked away by the enemy's large shield. I couldn't understand what happened. Was it possible that Gae Bolg, supposedly a sure-kill, didn't bring him down?

"Ugh..."

My head spun. My vision blurred. It seemed I had a concussion. I could feel blood trickling down my forehead. The physical protection from Sapphire was penetrated because I used magic power for Gae Bolg.

Sapphire:『Miyu-sama, are you alright?』

"... I'm okay. More importantly, Sapphire, what just happened?"

Sapphire:『... Probably, he avoided Gae Bolg by shifting the timeline. In other words, at the moment of the attack, the enemy wasn't there. Even Gae Bolg is ineffective if there's no target.』

So he had such an ability. He invalidated the reversal of causality by erasing his existence. In other words, the very result of the spear stabbing the heart was removed. The limited deployment Include ended, and Gae Bolg disappeared.

"What's that! Isn't that cheating?"

"At this rate, we might never reach a conclusion..."

Sapphire:『No, he probably can't use that ability in succession. This means, right now...』

"So, if I use Gae Bolg one more time, we can defeat him?"

"That's impossible, Ilya. We can't use Limited Deployment Include in succession."

"Ehh, is that so?"

Ruby:『You didn't know that, Ilya? It seems to result in an account ban...』

That's the way it is. In other words, I can't use the Lancer card for a while. I can use the Phantasmal Summon Install, but I don't want anyone to see that. Especially not Luvia and the others. That leaves only one option.

"The Lancer card can't be used. But I don't know if any other attack can penetrate that defense..."

"Yes, that's why we'll use the Saber card. If we use that sacred sword, surely..."

"That's a possibility."

Yes, if we use that sacred sword, it should be able to penetrate that defense. But for some reason, I couldn't assure myself of victory. I looked at the enemy again. The enemy was again standing guard in front of the castle gate, as if it was of great importance to him.

"Isn't it easy to attack right now?"

"Indeed."

"... Is it really?"

Despite Luvia and the others' words, I still expressed my unease. Is it really so? This enemy is clearly different from the others we've faced. Most enemies would prioritize attack, but this one uses his defensive power thoroughly.

I can't articulate it well, but I feel something like conviction. The presence of that conviction and its intimidating aura is many times, no, tens of times stronger when he stands guarding the gate of the castle. It's as if he's determined to protect it at all costs.

Sapphire:『But Miyu-sama, if we take too much time, he might be able to use that timeline shift again.』

"... Right."

There's no time to think. I determinedly pulled out the Saber card. There's no other choice if I can't use the Phantasmal Summon. We can't leave this space unless we defeat that enemy.

"Please step back. Class Card, Saber. Limited Deployment Include..."

I had Ilya and the others step back and applied the Saber card to Sapphire. Light filled the space and illuminated the surroundings. The moment I held the sacred sword, known as the strongest, in my hand, I felt as though the enemy was startled.

Even as I tilted my head at that, I glared straight at the enemy. Then the enemy raised his large shield towards the sky.

"It's useless, you can't possibly block the attack of this sacred sword!"

"... Here I go! Excalibur, the Sword of Promised Victory!"

In response to Tohsaka Rin's words, I unleashed the power of the sacred sword. The enemy stood still as the light approached, not trying to escape. It seemed like he was praying for something. And then, he swung down his large shield.

"I stand in the seat of calamity... It is our homeland that heals all scars and resentment... Reveal yourself...!"

The blackened heroic spirit spoke clear words for the first time. Could this be...

"Behold, Lord Camelot, the far-off Castle of Ideals!"

A Noble Phantasm!? The moment the enemy deployed his Noble Phantasm, the castle of white shone brightly. And then, a massive gate of light erected before the enemy. The magnificent gate seemed to be a conceptual aggregate capable of repelling all calamities.

The moment the light of the sacred sword collided with the gate, a tremendous explosion and shockwave wreaked havoc in the surroundings...