"Black" Caster swayed on the golem's back as it sped through the Hanging Gardens.
Despite his innate frailty, which rendered his physical abilities as a Servant extremely low, by using golems as his legs, he could move at speeds rivaling Servants with first-rate close-combat capabilities.
It would be a lie to say he felt no regret at all about betraying "Black."
Though there was no way to excuse it now, he felt a normal level of guilt. But that was that. He was a mage before he was a human. And before he was a Servant, he was merely a golem maker. What he sought was the Kabbalist's fervent wish: the recreation of humanity's progenitor, for which he had devoted his life.
Now, summoned as a Servant, he possessed the power to realize the dream he couldn't in life as his ultimate Noble Phantasm.
The Anti-Army Noble Phantasm, 'Golem Keter Malkuth - The Radiant Crown of Wisdom.'
Unlike the Noble Phantasms of many Servants, this was an unknown entity, not even completed by Caster in life, and he had never seen it in motion.
However, as his own Noble Phantasm, he understood its performance and power perfectly.
The problem was not defeating the enemy or obtaining the Holy Grail.
It was purely whether 'Golem Keter Malkuth' was the supreme masterpiece Caster had pursued.
He was prepared to be hated.
He might lose his life.
But such things were trivial before the noble ideal of activating the Noble Phantasm.
Caster now used telepathy to contact his former Master, Roche, from whom the connection was severed. Roche was unaware of the circumstances. He didn't know that "Black" Caster had defected to the "Red" faction and was now about to turn his fangs on the "Black" faction.
He had to draw Roche away before the other "Black" Servants informed the Masters of his betrayal.
If something happened to Roche, his hard-won betrayal would come to nothing.
Feeling sorry for Roche, who still called him 'teacher,' Caster conveyed the matter dispassionately.
Having betrayed his side, "Red" Saber nonetheless showed no intention of cooperating with the "Black" faction. Once he judged they had escaped enemy pursuit, he disappeared somewhere, taking his Master with him.
They would have liked to fight together if possible, but there was no time to stop and negotiate.
Caster's betrayal, the loss of the Holy Grail, the enemy leader being Amakusa Shirou Tokisada, the Ruler survivor of the Third Holy Grail War, who had brought all the "Red" Servants except the lone Saber under his control... For the "Black" faction, this was the worst imaginable situation. They had to formulate some countermeasure.
Emerging from enemy territory, they saw the Hanging Gardens had moved from its original position and was distancing itself from the Millennia Fortress. Despite the "Black" Servants' assault, it seemed "Red" Assassin had begun retreating with her entire territory.
"Phew, that was refreshing, Archer. Felt like we got a good shot in at that smug priest."
"Black" Rider smiled cheerfully, pleased that "Black" Archer had rejected the enemy's offer.
"I merely followed my own ego."
"Yes, but the question of what is important to humanity should be answered through humanity's exhaustive discussion."
Ruler firmly expressed her agreement with Archer's words.
However, both Archer and Ruler agreed that if humanity's salvation could be realized, nothing could be better. There had been hesitation. As humanity was now, bloodshed was inevitable in the end. To avoid that, removing the root cause was a logical approach.
But Archer could not waste the feelings of those who had overcome tragedy, and Ruler saw hope in humanity's future.
Humanity's salvation should be achieved by humanity's collective will, not forced by the ego of a single individual, and one from the past at that.
On the other hand, Shirou was convinced that leaving humanity as it was would never achieve peace.
This battle had already shattered the framework of the magical ritual based on the simple "Red" vs. "Black" structure. With Amakusa Shirou's appearance, the clash of faith and distrust in humanity itself had become the essence of this Great Holy Grail War.
"Archer. I can assert that the Great Holy Grail War has now completely deviated from its original course. If this continues, there is a high probability of a calamity on a global scale. Although it feels somewhat awkward to side with a specific faction, may I request your cooperation with the 'Black' faction?"
"That's reasonable. With Darnic gone, my Master will likely lead Yggdmillennia. I can't decide, but I'll sound out my Master in that direction."
"Please do."
At Servant speed, they could return to the Millennia Fortress without taking too much time.
However, even for Servants, moving on foot wasn't much different from humans. And generally, running speed was inferior to vehicles.
"That is...!"
"Black" Saber's eyes widened slightly as he looked at the fortress. Or, more accurately, at the giant figure standing erect on the fortress roof, and he was dumbfounded.
"'Black' Caster!?"
Ruler ground her teeth, her face grim.
The defected Caster had reached the Millennia Fortress ahead of the "Black" Servants.
"Red" Saber's Master, Shishigou Kairi, was pale-faced, propping himself up on the ground with his arms.
Above them was the departing 'Hanging Gardens of Babylon.' Although it had been flying relatively low to seize the Grail, for a human, it was still a considerable height. As a first-rate mage, Shishigou could indeed have managed to survive jumping from that height using airflow manipulation, gravity control, etc., even in his current attire. But Saber had involved him in a jet-like descent using 'Mana Burst.'
It was no figure of speech—he thought he would die.
"Saber, you..."
"Don't be so stiff, Master. Momentum's important, right?"
"Mentally, yeah! Not physically!"
"If you can yell that much, you're fine."
It proved that Shishigou's nerves were steady enough to shout after experiencing a bungee jump or jet flight without a safety rope. Health-wise, he was also fine.
"So, Master. What now?"
"What do you mean 'what now'? We gotta settle this. To get the Grail, we gotta team up with the 'Black' guys no matter what. Otherwise, it's pointless."
Even with "Red" Saber gone, the enemy was still overwhelmingly powerful. The situation was changing too rapidly to keep up, but to achieve the supreme objective of obtaining the Grail, establishing cooperation with "Black" was absolutely essential.
That was why he had pushed Saber to charge in recklessly. Now, the crucial point was the timing of contacting "Black." It would be best to form an alliance on as equal terms as possible, without letting the other side see their desperation. Fortunately—or not—"Black" was likely also in disarray due to Caster's betrayal. "Red" Saber, a powerful asset, would undoubtedly be highly valued as a replacement for "Black" Caster. Therefore, timing their approach to maximize their value was paramount.
"In that case, shouldn't we head to their place right now?"
"What?"
"That Caster guy, he's already gearing up for something."
"What!? Say that sooner! We'll fall behind!"
Shishigou's expression turned stern as he stood up.
Then, he stopped just as he was about to start running.
"Saber, what about the other 'Red' guys besides 'Black' Caster?"
"Huh? I'm here, aren't I?——Ah, I know, just kidding, don't make that scary face. Only Caster left. What can a mere mage do alone?"
Shishigou was slightly wounded by the word "scary face" that stuck in his mind but pondered Saber's words.
Then, shaking his head, he said:
"No, Caster originally belonged to the 'Black' faction, so it's very likely he knows the fortress's weaknesses. Also, we don't know how far the information about his betrayal has spread. And most importantly, him moving alone means he's that confident."
In Holy Grail Wars, the 'Caster' class is generally considered disadvantageous because the magecraft they excel at is easily negated by other classes with 'Magic Resistance.' However, on the flip side, a 'Caster' who has meticulously prepared and accumulated power can be extremely formidable, far surpassing modern mages. Thus, next to 'Assassin,' it's a class that could be called a Master's natural enemy.
"Black" Caster was also a golem maker. Golem attacks are physical, so the 'Magic Resistance' skill is almost meaningless against them. And regarding the aforementioned meticulous preparation, belonging to the "Black" faction, which had a longer preparation period than the Mage's Association's "Red" faction, he likely had ample time.
His Noble Phantasm was probably some form of powerful golem.
"Alright, let's go, Saber."
If "Black" Caster stirred up trouble for the "Black" faction, it would create bigger opportunities for them to intervene. To observe the situation and time Saber's entry, Shishigou decided to approach the Millennia Fortress.
In the Millennia Fortress, left behind after all Servants except "Black" Berserker had departed, were five Masters and the homunculi kept for miscellaneous tasks.
Although they had somewhat grasped the situation inside the Hanging Gardens by sharing Archer's vision, the feed had cut off during the battle with "Red" Rider, and telepathy also ceased. Fiore hurriedly checked her connection with Archer.
Archer hasn't been defeated.
Fiore's magical energy was still being supplied to Archer.
She knew the enemy's stronghold, the aerial fortress, likely had various mechanisms to prevent internal surveillance. Interference was expected, and observing the situation through "Black" Archer's eyes was now impossible. She asked Gord and Celenike as well, but they seemed equally preoccupied.
Of the five Masters, three—Fiore, Caules, and Gord—excluding Roche and Celenike, had gathered in the King's Hall, which functioned as a command center.
"Sis, where are the other two?"
"Locked up in their workshops because they're safe. Well, I understand the feeling."
The black mage Celenike and the golem maker Roche were both first-rate mages, confident in their skills. Especially Roche, who was utterly devoted to "Black" Caster, a golem maker superior to himself, stubbornly refused to leave the workshop they had built and managed together.
Minutes ago, "Black" Lancer's disappearance was confirmed on the spiritual board. The shocking event of the "Black" faction's standard-bearer being the first to fall made every cell in her body tremble. She couldn't show it on her face. But anxiety swirled within. Darnic wasn't responding either. Considering Lancer's death, the correct interpretation was undoubtedly that Darnic had also perished. If she could have used telepathy with Archer, she could have confirmed it.
Finally, a casualty had occurred among the Masters. And the first to fall was Darnic, the leader who oversaw everything, Yggdmillennia itself.
Who could have foreseen such a situation? A faction where its king and head fall first was nothing but absurd.
If Darnic truly was dead, Fiore would succeed him as head.
Unconsciously, Fiore clenched her fist on the armrest of her wheelchair.
"Sis? Is something wrong?"
"It's nothing."
Asked by Caules, Fiore realized her palms were sweaty. She must have been extremely tense. It was understandable. While magi prepared for death in the course of their magical pursuits, it wasn't that they weren't afraid to die. When starting a Holy Grail War, everyone resolved themselves to death while harboring an unfounded confidence somewhere in their hearts that they would survive. The more excellent the mage, the stronger this tendency. However, when the tide of battle turned unfavorable, and the possibility of disappearing without accomplishing or leaving anything became visible, remaining calm became difficult.
Although half-destroyed, the Millennia Fortress was still the safest place for now.
Militarily, it was unreliable, but having "Black" Berserker was reassuring. Against Dragon Tooth Warriors, with terrain effects and support from Fiore's magical devices, they could be defeated unilaterally. Preparations for interception were as complete as possible, so unless Servants directly stormed in, there shouldn't be a problem.
'Fiore, can you hear me?'
It was a telepathic message from Archer.
Feeling relief at the voice she felt she hadn't heard in ages, Fiore replied.
'Yes, I'm alright. What about you?'
'We just escaped enemy territory.'
'Are you injured?'
'No problem. And I have two pieces of bad news. One is that Lancer and Darnic were both killed. The other is that Caster has betrayed us.'
'What!?'
Regarding Lancer and Darnic, she had already somewhat resigned herself, so it wasn't shocking. Hearing it from Archer was painful and heart-wrenching, but she was prepared to accept it. However, the second piece of bad news was beyond unexpected.
'Wha-what do you mean!?'
'Caster is-'
Snap — the telepathy cut off.
External interference had forcibly severed the connection.
A few seconds later, a tremor that shook the Millennia Fortress ran through the King's Hall.
"Wh-what was that!?"
"Viiiiiiii!"
Berserker roared, grabbed Caules and Gord, and fled the room. Despite her girlish appearance, Berserker was a Servant and a homunculus. Carrying the weight of two grown men was trivial. Following her, Fiore, aided by her enhanced-connection magical device, Bronze-Link Manipulators, followed Berserker.
A section of the castle wall collapsed, and dust surged from behind.
Creating an air mask with magecraft to avoid inhaling dust, Fiore shouted to Berserker, who was dashing down the corridor.
"Berserker, let's get outside from that terrace! The enemy knows our location! We're at a disadvantage indoors!"
Thinking they could confuse the enemy by running around inside was premature. Given that they had been precisely targeted after moving from their initial location to the King's Hall, the enemy could likely snipe at them from outside while they fled indoors. In that case, only their side would be blind, and being inside the fortress offered no advantage for counterattacking or escaping.
"You heard her, Berserker! Outside!"
"Vii!"
Hearing Fiore and Caules, Berserker kicked through the terrace window and leaped outside. Fiore followed without delay, evacuating outdoors. Of course, the attacker would likely be there, but she judged it better than being attacked one-sidedly.