The Archangel Metatron was a being renowned for her sheer enormity.
It was said that she possessed ten graces, 1,365,000 blessings, seventy-two pairs of wings, 365,000 shining eyes, forty-nine gems, and a crown.
This most exalted angelic form, one that pushed human imagination to its limits, was the being closest to God, praised as the Scribe of God and the Chancellor of Heaven.
Over the course of a week, the "Hanging Gardens of Babylon" had been completely transformed into a true throne of God.
The idea that the Queen of Assyria, Semiramis, had built the Hanging Gardens existed only as a legendary anecdote. The true builder of that marvel was Nebuchadnezzar II, the legendary monarch of Mesopotamia.
In the Old Testament, Nebuchadnezzar II is described as the instrument God used to punish the Jews who had rebelled against Scripture and strayed from the faith, and the Hanging Gardens he built are regarded as the prototype of the Tower of Babel.
In his later years, this king was punished by God for his arrogance and transformed into a mad Beast. That experience is also considered the original source for the fallen angel Lucifer.
Surrounding the newly born divine throne were countless angels brought forth by Metatron.
After a week of proliferation, the Angelic Host had reached the number of one million.
How to break through that million-strong army of angels was the greatest problem Shirou and the others faced.
Time turned back to the early morning three days earlier.
In a conference room inside the Fortress of Millennia, the participants of the Great Holy Grail War sat around a huge round table.
"What is this...?"
Lying across the table was an "unidentified creature" whose body was tightly bound by dark green chains, its palms and ankles pierced and pinned down by pitch-black arrows.
It stood over twenty-five meters tall, and its faceless body was covered in muscles so developed that even Spartacus would not surpass it by much.
Pure white skin, snow-white wings, and a golden halo.
Shirou said, "This is an Angel."
"Eeeeeeeeeeeeeeeeeh!?"
Everyone screamed.
"An-An Angel?"
"Why is an Angel here?"
"Saber, did you capture this!?"
Shirou nodded. "It wasn't just me. Archer and Assassin helped too.
Without their assistance, there's no way I could have done this alone."
Atalanta Alter stood there gallantly with one hand on her hip, looking as if it were only natural. Semiramis, meanwhile, crossed her arms beneath her chest, snorted, and turned her face away.
Everyone suddenly understood.
So that was it. The greatest female hunter of Greek mythology, together with the demigod Empress of Poison. If those two worked together,
Then yes, even capturing a higher-dimensional being like an Angel was not impossible.
Fiore covered her mouth in surprise. "So that's why Saber-sama snuck out with the two of them last night. I thought..."
What did you think we were going out to do?
"Saber, why did you capture an Angel?"
Kairi Sisigou asked with a puzzled look. "Even if you capture one or two Angels, it doesn't mean much, does it? There are a million of them."
"When I first saw these things, I came up with a certain hypothesis. Capturing one was to verify that hypothesis."
As Shirou spoke, he projected a strangely shaped knife into his hand and sliced open the Angel's pure white skin.
"These things are robots."
"What!?"
Everyone stared in shock at the Angel's insides. What lay within was not living flesh and blood, but mechanical cables and circuits.
"I can't believe it... So the truth about Angels is that they're machines, vessels loaded with the Authority of God..."
"But that does explain why so many Angels in religious paintings look like monsters with strange forms."
"I heard the modern image of Angels was influenced by Greco-Roman mythology in the first place. It wasn't Cupid who copied Angels, it was Angels that copied Cupid's appearance."
"No wonder some Angels look like wheels. They really are the vehicles of Heaven."
"Ahh, Angel-sama, please forgive our disrespect and pardon Master's sin..."
The Magi threw in comments one after another, discussing the matter heatedly, while Leticia shrank her shoulders and prayed in terror.
The Rider of "Red" observed the Angel pinned to the table and said, "That helps a lot. Since we know the enemy is mechanical, it'll be much easier to understand how to fight them."
Shirou glanced at him. "Rider, are you an idiot?"
"Hah? You want to fight?"
"All right, all right, stop arguing."
Caules stepped between them with a wry smile.
Shirou said mockingly, "Are you seriously planning to go hand-to-hand with a million Angels?"
Monotheistic legends did speak of saints, or superhumans, who fought a million Angels and won, but those were exaggerated accounts from later generations.
Angels were vessels of the Lord's power.
If they were only Angels of the Ninth through Fourth Ranks, it would still be manageable. From the Third Rank onward, however, they were already true deities, giant-like beings in every sense.
In fact, even with Shirou, Atalanta, and Semiramis working together, they had only succeeded in capturing a Fourth-Rank Angel. They could not capture a Third-Rank Angel without destroying it.
Shirou said, "I didn't go to all this effort to capture and dissect this thing just so we could study how to fight it."
"Then what are you planning to do?"
"You don't even know that?"
Shirou narrowed one eye smugly, and everyone suddenly felt that today's Saber was especially punchable.
"I'll give you a small hint. The answer is right here."
The red-haired boy pointed toward the Angel's head.
Above its thick chest and shoulders, and below the enormous angelic ring, there was no head. In its place was an oval recess shaped like a wok.
"It clearly imitates the structure of a human body, yet it alone has no head. In other words..."
Fiore's eyes widened. "These Angels don't have the ability to think!"
Shirou nodded along. "Exactly. These mechanical lifeforms have no capacity for thought. Perhaps vessels for the power of God don't need self-awareness.
They're connected through a thought network, carrying out patrol and combat duties.
The oval recess on their shoulders is a signal receiver. Doesn't it look just like a TV signal receiver?
And the halo above this one's head serves to amplify the signal and relay it to its companions."
Under everyone's stunned gazes, Shirou revealed the truth of the Heavenly Legion.
"The command center transmitting orders to one million Angels is none other than Metatron's throne.
But even an Angel's throne can't fully coordinate one million individuals by itself. The Angels relay signals to one another through their halos.
The Nine Orders of Angels are not a classification of how strong their Authority is. They represent the network layers of the Angels.
What we need to do is hack into their network, then force the angelic army to kill one another."
Leticia blinked. "So that's why Archangel Metatron gave us a final seven-day limit. It wasn't mercy at all..."
Archangel Metatron had already fully manifested, and her power had reached its limit. If she wanted to summon one million Angels at once, she could do it.
However, Angels summoned abruptly were only vessels that stored the power of God. She first needed to construct the angelic command network, which was why she left them seven days.
"You say we're going to invade the enemy's network, but even if they're machines, Angels are still higher-dimensional beings!"
Gordes shouted excitedly, "Can we really do something like that...!?"
"I may not look it, but I'm something of a mechanical expert."
After saying that, Shirou rubbed beneath his nose. At last, everyone understood why he had been acting so smug today.
Fiore said, "T-That's the first I've heard of it, Saber-san. Do you have experience modifying mechanical lifeforms?"
Shirou said, "No. I can repair electric heaters and motorcycles."
Fiore said, "???"
At this point, they could only trust Shirou's judgment and confidence.
Come to think of it, all of them had survived until now because he had saved and helped them.
Although they acted unimpressed, everyone believed in this Holy Sword User from Britannia from the bottom of their hearts.
Seeing that no one objected, Shirou announced, "The final operation against Metatron's army... Operation Code, 'Achilles' Heel.'"
"Hah?" Rider, Achilles, frowned.
The reason for that name came from a Hollywood movie Shirou had once watched.
For a while, Irisviel had been obsessed with science fiction films, so she dragged Shirou, Sella, and the others along to watch them with her.
The subject was the familiar story of humanity resisting an alien invasion. Faced with an alien army whose civilization far surpassed Earth's, modern armies were defeated again and again.
The gap in strength was so overwhelming that it drove the audience to despair.
But in the middle of that unsolvable situation, the human protagonist would accidentally discover the weakness, or rather, the vulnerability, of the seemingly invincible aliens.
At the end of the film, humanity successfully exploited that fatal vulnerability to turn defeat into victory, repelling in one stroke an alien army a million times stronger than itself.
Shirou regarded the aliens' weakness in those kinds of movies as their "Achilles' Heel." What they had to do next was exploit the vulnerability in the Angel Network and turn the battle around.
The plane Shirou was riding in had tried to approach the Divine Throne several times, only to be met each time by pillars of flame with firepower equivalent to the Holy Lance.
"Master! What do we do now? At this rate, we'll never get close to Metatron-sama!"
Leticia was growing anxious, but Shirou remained calm.
"From here on, we'll have to rely on your strength."
"Me?" Leticia blinked.
While observing the situation outside the cabin, Shirou asked, "Leticia, do you know Jacob's Ladder?"
The girl nodded. "Of course I do."
In the Book of Genesis from the Old Testament, it was the vision Jacob saw while fleeing from his brother Esau.
He had a dream in which he saw a ladder standing on the earth, its top reaching into Heaven, with God's messengers ascending and descending upon it.
God appeared above the stairway that led to the sky and reaffirmed His covenant with Abraham to Jacob, promising him land, descendants, and blessings.
Leticia looked completely lost. "...So what does that have to do with our situation?"
Shirou placed his hand on the girl's shoulder and said, "The 'ladder' leading to the throne of God is inside you."
"...Eh?"
"Jacob's Ladder... Or perhaps it should be called Jeanne's Ladder. No, Leticia's Ladder would be more accurate."
"Pray, Leticia! Use your power to summon the ladder! Open a path for us!"
"This is way too sudden! Why didn't you tell me about this part of the operation earlier!?"
"If I'd told you beforehand, you definitely would've gotten nervous and frozen up."
"All right, stop worrying over it... Go, Leticia! Humanity's fate rests on you!"
"Eek...♡"
He had only meant to slap Leticia's bottom to encourage her.
Feeling the soft, full sensation in his palm, Shirou was secretly startled. This girl was far too well-developed, wasn't she?
"F-Fine, I'll try... But don't blame me if it doesn't work, okay?"
Leticia muttered unhappily as she knelt on the cabin floor and brought her hands together.
The girl's slender back was bathed in light, and in Shirou's eyes, for an instant, she once again overlapped with Jeanne.
Before long, it was as if infinite light poured out from her small body.
The clouds beneath the throne split open, and radiance spilled down.
Dozens, even hundreds, of rectangular glass panels descended from above in layers, forming a stairway to Heaven.
"It really... worked..."
Even Leticia herself had not expected it to succeed.
Shirou had prepared a Plan B, and he had not been especially confident in it either.
Looking at the staircase of light descending from the sky, he happily ruffled the girl's hair. "Well done."
However, Leticia did not seem pleased. She dodged Shirou's hand.
"?"
"Master, don't keep patting my head. I'm not a little kid anymore."
A faint blush colored the girl's cheeks as she pouted adorably.
"..."
Just an hour ago, she had happily let him pet her. What had changed?
Leaving the girl's worries aside for now, saving the world came first.
The golem piloted the plane near the stairway to Heaven.
A civilian airliner could not hover like a flying craft or a helicopter, so they had no choice but to jump.
Leticia clung tightly to Shirou's waist as she fell with him onto one section of the stairway.
"Safe landing. Phew... I really thought we were going to fall."
Leticia, on the other hand, was deathly pale, her arms still locked tightly around Shirou's waist.
"We're safe now."
Shirou said that, but the girl still hugged him tightly and refused to let go.
"S-Sorry, but..."
It was only natural that Leticia would be too frightened to move.
After all, the so-called stairway to Heaven was made up of hundreds of glowing rectangular glass panels, each suspended in midair with no connection between them.
If she fell, now that she no longer had the Holy Maiden's protection, certain death awaited her.
"Leticia, give me your hand."
The girl looked up at Shirou, then hesitated before nodding and letting go of him.
"D-Don't let go, okay...?"
And so, Shirou held Leticia's hand and climbed toward the throne a thousand meters above.
It's so scary... It really is still so scary...!
Leticia's legs would not stop trembling.
Yet as time passed, that trembling gradually faded.
The warmth and strength coming from Shirou's palm gave her an indescribable sense of security.