Saber gripped the golden-radiant Holy Sword with both hands and crooked the corners of her mouth upward.
"Don't hold me back... I'll return those exact words to you.
Demon Sword Wielder, if you can't keep up, remember to tell me. I'll make up for your share of the work."
"Worry about yourself. Holy Sword Wielder."
Shirou and Saber charged toward the countless monsters while trading barbs.
"------!"
Golden starlight and black auroras illuminated the forest in the darkness in an instant.
"...Amazing."
Irisviel stared wide-eyed at their blood-soaked figures.
The Holy Sword and Demon Sword swept through the monsters like scythes through grass, annihilating wave after wave of otherworldly fiends.
Hordes of tentacled monsters surged forward endlessly, only to be cut down the instant they approached the two.
Having just fought the monsters herself, Irisviel knew very well that these misshapen creatures were not enemies that were useless beyond their numbers.
They were brimming with vitality and mana, built more like weapons than living things, with lethal teeth and suckers covering their bodies. They were demons born to ravage humanity.
Yet before the Holy Sword Wielder and Demon Sword Wielder, the monsters could only become the ones being ravaged.
Several minutes later, the forest had been transformed into a filthy mire.
They fell in swathes like harvested wheat. Layer upon layer of corpses and hills of flesh mixed with entrails and bodily fluids scattered across the ground, forming a chaotic scene more horrifying than hell itself.
The monsters' organs gave off a nauseating stench of rot while producing a poisonous miasma. Any human without magical aptitude would probably die of lung decay after inhaling even one breath.
With the projected "Excalibur Morgan" and Lady Avalon's magecraft, Shirou had received an immense enhancement.
But he had not used his trump card, "Dead Count Shapeshifter." In terms of physical ability, Shirou still fell far behind the Three Knights, with a gap he could not bridge.
Even so, relying on his swordsmanship and experience, Shirou displayed battlefield prowess that was in no way inferior to Saber's.
What was most astonishing was the tacit cooperation between him and Saber.
Yet this was their first time working together. In fact, they had only spoken for the first time today, but they seemed like comrades and fellow warriors who had fought side by side for many years.
Every movement and every act of covering for each other flowed smoothly, perfectly seamless, as if they had rehearsed it beforehand.
To Irisviel, it was practically the latest Hollywood action movie.
As for the two involved, they felt that mutual understanding even more deeply.
Beneath Shirou's bone mask.
Above Saber's dignified beauty.
Both of them wore faint, nearly imperceptible smiles from the pleasure and exhilaration of battle.
In just over ten minutes, they had destroyed more than five hundred monsters.
Even so, the number of tentacles showed no sign of decreasing.
Even after fighting to this extent while drenched in blood, Artoria's elegant beauty had not suffered the slightest blemish.
Shirou's mask made his expression impossible to see, but judging by his natural breathing, he was under just as little pressure.
Saber leaped backward and spoke with her back against Shirou's.
"Have you noticed, Demon Sword Wielder? It's that Grimoire in Caster's hands.
As long as he still holds that Grimoire, the monsters will continue multiplying without end."
Shirou nodded and uttered, "Mm."
While cutting down the monster pouncing on Shirou's left, Saber playfully raised the corner of her mouth.
"Looks like you failed to notice, Demon Sword Wielder."
Shirou swung his sword and severed the monster on Saber's right at the waist, refusing to yield.
"Looks like you're so tired you've started talking nonsense, Holy Sword Wielder."
Shirou had actually discovered the truth long ago.
It would be more accurate to say that he had understood the principle the moment he first saw Caster.
That human-skin Grimoire of Caster's was essentially a Mana Core.
Like the "Dead Count Shapeshifter" on the back of Shirou's hand, it not only stored an enormous amount of mana but also had preprogrammed spells embedded within it.
Caster himself could not even use magecraft. He had always relied on that book to cast spells.
Before this, he had opened a passage to another world in the forest through a living-sacrifice ritual.
As long as the Grimoire continuously supplied the mana needed to maintain the space-time passage, it could summon monsters indefinitely.
That was the truth behind Caster's inexhaustible generation of tentacles.
"Now that we know the secret behind the monsters' endless reproduction, there's only one thing we can do."
Saber turned her face aside and spoke to Shirou in a provocative yet expectant tone.
"Since you're holding that sword, you should be able to do the same thing I can, right?"
Saber's words were vague, but Shirou immediately understood her intention.
"You'll clear the monsters from the path, and I'll deliver the final blow to Caster."
Saber nodded. "Mm. Let's do that. Show me your aurora once again."
They did not even exchange glances. With their backs pressed together, they confirmed each other's intentions.
"What are the two of you whispering about? Prayers before death?"
Caster stood about a hundred meters away from them, constantly hurling taunts their way.
The opponent fighting Shirou and Saber now could be said to be his Noble Phantasm, "Tome of the R'lyeh," rather than Caster himself.
Caster was like a spectator watching from a safe zone. All he had to do was put on a relaxed air and occasionally add a curse or two to provoke his enemies' emotions. That alone counted as an attack.
"Taste terror! Sink into the abyss of despair!
You'll be drowned and suffocated by these monsters without glory or honor!
That must be an unbearable humiliation for heroes!
Ah, yes... Let's see that beautiful face of yours twist in pain, Saintess!"
"Unfortunately, I'm not a hero."
"Unfortunately, I'm not a Saintess either."
Shirou and Saber stepped forward almost simultaneously, but the Holy Sword Wielder's girl was the first to unleash her attack.
"Gale Force Hammer!!!"
Brilliant golden radiance erupted. The gale spiraling from the blade compressed the surrounding air into a mana-filled shockwave that shot in a straight line toward Caster a hundred meters away.
Between Saber and Caster stood a wall of flesh formed by thousands of loathsome monsters, but they did not even have time to react before bursting apart beneath the wind shockwave, which struck like a slash.
In the blink of an eye, hundreds of tentacles had been torn apart, yet "Gale Force Hammer" showed no sign of weakening. It continued forward, crushing Caster along with them—
But a mass of enormous tentacles suddenly burst from the ground before Caster.
They were defensive magecraft Gilles de Rais had prepared in advance. There was no way he would appear on the battlefield without any precautions.
"—Bang!"
The tentacles, thick as trees, still could not block Saber's slash of wind.
Although they were blasted into a mangled mess, they served as a temporary meat shield and bought their master time to escape. Caster rolled and crawled out of the range of "Gale Force Hammer."
But—this had also been within Saber's "Instinct."
From the beginning, she had never expected to kill the seemingly mad yet actually cunning Caster so easily.
Breaking through his defensive magecraft was enough.
The rest could be left to the person she trusted.
"Hah... hah... hah..."
Caster had escaped by the skin of his teeth. Supporting himself with both hands on his knees, he raised his head, preparing to continue taunting them, only to see the figure of the Angel of Death.
"Vortigern—"
The air surged, and mana boiled.
Shirou raised the Reversed Holy Sword high and calmly roared the name of Britain's tyrant.
"Vortigern----!!!"
The second impact came after "Gale Force Hammer."
Though it was already night, a color deeper than the darkness appeared.
It was a black aurora that swallowed all light.
Like the Evil Dragon's Breath ravaging an island nation, it savaged the earth and forest, burning everything around it to ashes and turning it into scorched earth.
"Ahhhhhhhhhh!"
Gilles de Rais vanished into the radiance with a scream.
The dragon's breath pierced through the forest and broke into the sky, continuing until it completely merged with the night.
Once the black radiance faded from everyone's vision,
all the otherworldly monsters had been reduced to pools of blood. The army of tentacles from moments ago seemed never to have existed at all.
In the silent forest, only Caster remained, most of his body burned away, along with the "Tome of the R'lyeh" lying on the ground.
"Ugh... It's not over yet. I haven't saved Jeanne yet..."
Perhaps because he had absorbed enough life force from the citizens of Fuyuki City earlier, Caster still had not died despite being reduced to his upper body, with even his Spirit Core shattered.
He stubbornly crawled toward the Grimoire.
Just before he could reach the "Tome of the R'lyeh," Shirou pinned his hand to the ground with his sword, then picked up the evil Grimoire made of human skin in place of the howling Caster.
No matter how loathsome he had been in life, after death Caster still turned into beautiful golden motes and scattered on the wind.
When a Servant returned to the Heroic Spirit Throne, their Noble Phantasm should vanish as well.
Yet strangely, the "Tome of the R'lyeh" did not disappear.
Curious, Shirou decided to study this wondrous Grimoire carefully.
"Let's see. What country's writing is this...? It isn't English. I can't understand it at all...?"
"Hehe, it's Italian."
Shirou turned around and found Irisviel smiling sweetly behind him, her long hair falling forward as she bent over, nearly brushing his cheek.
"You can read Italian?"
"Mm-hm. Are you interested in this book? I can read it aloud for you."
The Silver-haired homunculus placed both hands on Shirou's shoulders and began reading the words on the page.
It seemed to be a book recording strange creatures from ancient times. Its language was obscure, and a strange, inexplicable eeriness permeated every passage.
"Irisviel."
Saber approached with an expression of displeasure. "Are the two of you planning to stand here and hold a book club forever?"
They had just gone through a deadly battle, yet these two were standing amid a mountain of corpses and a sea of blood reading a book. Wasn't that a little too insensitive?
Seeing the displeased Servant, Irisviel covered her lips. "Oh my, Saber, are you jealous?"
"Wha...!"
Saber glanced at the black-haired boy pressed close to Irisviel and frowned. "Why would I have to be jealous of you?"
Before you continue