After Shirou's group entered what appeared to be a mountainside but was actually a cavern, both Rin and Illya immediately took out their Mystic Codes and magical tools, ready to launch an attack at any moment.
Shirou still took the lead.
He was wearing a blue-and-white long-sleeved shirt stained with traces of blood. The sleeve covering his right arm had been torn apart when he removed the Shroud of the Holy Remains earlier, making him look thoroughly disheveled.
Yet despite his appearance, he looked calmer than anyone else present.
Even though releasing the arm had filled his mind with countless memories that did not belong to him, along with other things he could not even begin to describe.
Shirou did not pay much attention to any of it.
If he could not think clearly, then he would simply stop thinking.
Right now, there were only two things he needed to do.
Defeat the enemy.
Protect the two people behind him.
Nothing else mattered.
He only needed to accomplish those two things.
No one understood his condition better than he did.
Having all sorts of things forcibly crammed into his body was an incredibly painful experience, especially because every time he needed to use that power, he would inevitably be in the middle of a battle.
The more he drew upon the arm's power, the more Shirou felt as though his body was no longer his own.
Yet at the same time, he could clearly feel his strength growing at a visible rate.
This was the price of obtaining tremendous power in a short period of time.
But he did not become intoxicated by it.
Shirou understood exactly what this power was meant to be used for.
That was one of the main reasons its original owner had entrusted this arm to him.
It was also what he himself wanted.
And yet...
He did not understand why he wanted it.
Compared to the memories contained within the arm, the existence known as Emiya Shirou was simply too insignificant.
Emiya Shirou was merely an ordinary person.
A boy with an idealistic dream who continuously strove toward it.
But Archer was not ordinary.
Whether it was magecraft, ideals, logic, or conviction, he surpassed Shirou by an immeasurable margin.
After all, Archer had become a Counter Guardian.
A Heroic Spirit.
A being who had reached the destination Emiya Shirou had always sought.
...
What destination?
Whether intentionally or not, the overwhelming flood of memories was gradually washing away one particular memory.
If given enough time, he felt that he could probably recall it.
Unfortunately, he no longer had the luxury of spending time wondering what that lost memory was.
"Saber."
Looking at the figure before him, Shirou quietly spoke her name.
She had removed the visor covering her eyes.
With her eyes closed and both hands resting atop the hilt of a sword planted into the ground, she resembled a devoted guardian standing watch.
"So you have come."
Upon hearing Shirou's voice, Saber opened her eyes.
In the darkness of the cavern, her pupils seemed unusually bright as she fixed her gaze directly upon him.
Grasping her sword and pulling it from the ground, she continued,
"The only order I received was to stop you, Shirou."
"Yeah... That is probably the first piece of good news we have had in a while."
The moment Rin heard those words, she immediately understood their meaning.
Though she called it good news, she knew perfectly well that for her, it was actually the worst possible situation.
"Come on, Rin."
After examining Saber and then glancing toward Shirou, Illya was the first to move forward.
Fighting alongside him was impossible.
She knew very well that, at this moment, the only person capable of facing a Servant was Shirou.
Even Rin, armed with their trump card the Jeweled Sword, might not be able to fight Saber directly.
Since Saber was allowing them to pass, they naturally chose to accept that kindness.
When she reached Shirou's side, Illya stopped briefly.
"Shirou... Do not die, okay?"
She did not look at him.
She understood better than anyone how terrible his condition currently was.
"Otherwise, all that black mud inside the Grail will spill out. And then a lot, a lot of people will die."
At this point, there was no turning back.
Rather than trying to persuade him otherwise, she chose to provoke him with her words and push him forward.
Perhaps...
That might give him the slightest chance of victory.
"And there is still at least one more Servant waiting ahead. So hurry up and catch up with us, Shirou."
The moment Rin heard Illya's words, she understood exactly what she was trying to do and added her own remark.
Saying such things at a time like this would only place additional pressure on him.
But Rin knew Shirou well enough to understand that he would not be crushed by something like that.
On the contrary, as long as there remained something that only he could accomplish, he would find a way forward no matter what.
"Yeah. I understand."
Shirou answered simply.
He did not spend much effort thinking about what they had said.
Or rather, he was incapable of doing so.
At that moment, the only thing visible in Shirou's world was Saber standing before him, gripping that black holy sword.
Defeat her.
The thought repeated endlessly in his mind.
Both he himself and the other presence within his head shared that same conviction.
After all, this battle would determine whether he could continue moving forward.
And it was also something he had to do as Saber's former Master.
As her friend.
Only after Rin and Illya had disappeared from sight did Shirou take a deep breath.
Then he began unwrapping the Shroud of the Holy Remains.
This time, Shirou even removed the bindings around his wrist.
The crimson Shroud of the Holy Remains fluttered in the wind flowing through the cavern, drifting through the air before slowly, very slowly, falling to the ground.
The instant it touched the floor, a pair of black-and-white swords appeared in Shirou's hands.
They were the weapons he currently considered the most efficient and practical, Kanshou and Bakuya.
Without hesitation, he launched the first attack.
The moment Shirou took his first step toward her, Saber raised her sword and swung it down at him.
Twin blades and holy sword collided.
Once.
Twice.
Three times.
He projected another pair of blades and clashed with her again.
Shirou knew exactly where his limits lay.
In terms of strength and speed, he could not compare to the Saber before him.
As for magical energy, there was no need to mention it.
Although Illya and Rin were supplying him with some mana, it was nowhere near enough to match Saber, who was directly connected to the Grail.
A prolonged battle offered him no advantages whatsoever.
The optimal solution was to fight with everything he had and end things as quickly as possible.
Every minute that passed drained more of his stamina and magical energy.
The longer the fight lasted, the worse his disadvantage became.
Faster.
Shirou continued accelerating.
With every projection and every swing of his blades, he could clearly feel something filling his body.
The speed and precision of his projections improved.
The speed of his swordsmanship increased.
The existence known as Emiya Shirou was gradually moving closer and closer to becoming the Heroic Spirit Emiya.
"Archer's arm... I see."
As his opponent, Saber naturally noticed the changes.
At first she had been able to fend him off effortlessly.
Then she needed to devote some attention to defending.
Now she had begun channeling magical energy simply to keep up with his attacks.
The dissatisfaction and confusion she had felt earlier when Shirou chose to project Archer's weapons instead of a stronger holy sword finally had an explanation.
"Hah!"
Without saying anything further, Shirou slammed his battered twin blades against Saber's sword and used the recoil to propel himself backward.
While still airborne, a black bow and arrows materialized in his hands.
He immediately fired toward Saber.
"Pointless."
Facing the barrage, Saber did not even bother to dodge.
She allowed the arrows to strike her armor before falling harmlessly to the ground.
Yet in the very next moment, the arrows lying on the floor began to glow.
Then they exploded.
Dust and debris engulfed Saber's position.
Shirou did not lower his guard.
He immediately fired several more arrows into the smoke before projecting Kanshou and Bakuya once again.
"Haa... haa..."
As he struggled to regulate his breathing, his gaze remained fixed on the cloud of dust.
Whoosh—
The sound of a sword cutting through the air echoed through the cavern.
The smoke surrounding Saber was instantly blown away.
Her armor bore visible damage.
But only her armor.
Nothing more.
"Is that all?"
Holding her sword in one hand, Saber looked at the heavily breathing Shirou.
"Are you already finished?"
She understood perfectly what price Shirou was paying to continue fighting.
For swordsmen, the best way to communicate was through their blades.
"Of course... not!"
Gritting his teeth, Shirou tightened his grip on his twin swords and charged once more.
There was not much time left.
Although magical energy was still being supplied to him, most of his stamina had already been exhausted.
And...
At some point, black mud had begun flowing into the cavern.
To Saber, it was an ally.
To him, it was a deadly poison.
It seemed that neither timing, terrain, nor fortune was on his side.
But retreating was impossible.
Even if he shattered his teeth from clenching them, he would still keep moving forward.
The pain from overtaxing his stamina, magical energy, and Archer's arm continuously assaulted him, forcing him to remain painfully aware of every moment.
Even if he died here—
He had to defeat the enemy before him.
"Good eyes."
Watching Shirou rush toward her, Saber spoke.
For a brief instant, Shirou thought he saw the corner of her lips curl upward ever so slightly.
"──"
A sharp pain erupted in his brain.
It prevented him from dwelling on the meaning of Saber's expression.
Instead, he surrendered himself to instinct and continued swinging his twin blades.
"Have you already reached your limit?"
Although Shirou's movements had not slowed and the power behind his strikes had not weakened, Saber still arrived at that conclusion.
Shirou had already reached the maximum burden his current body could endure.
If he continued...
Only self-destruction awaited him.
Saber understood this clearly.
Yet she did not stop swinging her sword.
In contrast, Saber began drawing upon even greater magical energy than before.
Since her opponent was fighting with such conviction in his beliefs, she felt she should respond in kind.
"Guh..."
Saber's sudden surge of power caused Shirou to misjudge the limits of the twin blades in his hands, and he took a direct hit from her sword.
Fortunately, he reacted in time and barely avoided the full force of the strike, preventing himself from being cut down on the spot.
It would be more accurate to say that he did not react on his own. Rather, the vast amount of combat experience in his mind that did not belong to him allowed him to evade the crisis at the last moment.
Even so, if the wound from that strike was not treated quickly, Shirou estimated that within ten or twenty minutes he would lose the ability to fight due to blood loss.
Recalling, thinking, searching. Shirou continuously pushed his mind to its limits, trying to break through his current predicament.
Nine Lives?
Rejected. At this distance, the time required to project it would be enough for Saber to kill him first. Besides, she might even be capable of matching the Nine Lives strike he could imitate.
After all, it was only a copy. The burden was immense, and his body might not withstand using it again.
Saber's sword?
Rejected. For the same reasons. Projecting it would be even more difficult than the axe-sword and would exact an even greater price.
Then he could only search through the techniques and Noble Phantasms that Archer himself possessed.
Deploy Unlimited Blade Works?
Rejected, the mana cost too high, and it would not be especially effective against Saber.
Other projected Noble Phantasms?
Caladbolg?
Rejected. If the explosion was too small, it would do no damage. If it was too large, it might collapse the cavern. The reason Saber had not been using overwhelming amounts of magical energy was because a single mistake could bring the entire place down.
...Then there was only Kanshou and Bakuya.
As Archer's most frequently used Noble Phantasms, there had to be a corresponding combat strategy for them.
—Search complete.
Letting out a heavy breath, Shirou projected the black-and-white twin blades and threw them forward.
Such a straightforward attack was naturally dodged by Saber, who immediately charged toward the now unarmed Shirou.
Yet Shirou neither lost heart nor was he panicked. Instead, he projected a second pair of Kanshou and Bakuya and used them to intercept her assault.
Kanshou and Bakuya possessed the property of mutual attraction. As long as one held Kanshou, Bakuya would inevitably return to its side.
Combined with the nature of Projection, this made a continuous chain attack possible. It was a finishing move unique to Archer, or more precisely, to the Heroic Spirit Emiya.
"!"
While focusing entirely on the twin blades in Shirou's hands, Saber seemed to notice something. She glanced backward and saw the white blade flying toward her from behind. While blocking Shirou's attack, she simultaneously evaded the blade streaking toward her back.
"Hmph—"
But Shirou did not stop. He continued pressing the attack.
At the same time, the Kanshou he had thrown earlier returned, flying toward Saber's back.
In that brief instant, Saber relied on her extraordinary intuition to dodge the returning Kanshou with the smallest possible movement. At the same time, she swung her sword with all her might, shattering the black-and-white twin blades in Shirou's hands.
However, the price of dodging and delivering that powerful strike was that her chest was left completely exposed.
Seizing that fleeting opportunity, Shirou projected a third pair of black-and-white blades.
This time they were longer, resembling a pair of black and white wings.
"Sa—ber—!"
Pouring every ounce of strength into a hoarse roar, Shirou raised the twin blades and slashed forward at the opening he had deliberately created.