The power displayed by the three Servants was indeed comparable to modern weaponry, perhaps even surpassing it. After all, while Lancer might be fighting at his full strength, Artoria and Ailin were not.
Lancer, summoned in the Lancer class, wielded two Noble Phantasms effective against individuals. While powerful, they couldn't cause widespread destruction. Artoria's Excalibur, however, was a weapon capable of leveling cities. A single strike, unleashed at its full power, could obliterate the entire port.
Ailin, too, possessed similar destructive potential. He even had Zanpakutō capable of destroying the entire city of Fuyuki.
Attributes, skills, and combat prowess determined a Heroic Spirit's baseline strength. But their Noble Phantasm defined their upper limit. Gilgamesh, for example, wasn't the strongest in terms of attributes, skills, or swordsmanship. But he was considered the strongest Heroic Spirit because of his Noble Phantasm, Ea, the Sword of Rupture. It was a weapon capable of severing the very fabric of the world, returning it to primordial chaos. While Gilgamesh couldn't unleash its full power, even its partially unleashed form was enough to place him at the pinnacle of Heroic Spirits.
Compared to a magus like Irisviel, the power displayed by Ailin, Artoria, and Diarmuid was comparable to a modern army, perhaps even exceeding it. In fact, a modern army attempting to subdue a Servant would likely suffer heavy casualties with little to show for it. While not at their full power, Servants were still Heroic Spirits, their strength amplified by "mystery."
"Mystery is lost in the face of greater mystery." The converse was also true. In the face of greater mystery, lesser mystery was simply… mundane. Modern weapons, their workings widely understood, had lost their "mystery." Against a Servant, imbued with greater mystery, they were ineffective.
Ailin recalled the Fourth Holy Grail War, where Gilles de Rais' summoned sea monster had been attacked by fighter jets and missiles. The attack had been futile. Only after Lancelot, fueled by Mad Enhancement and his "Knight Undying With Empty Hands" skill, imbued a missile with "mystery," transforming it into a C-rank Noble Phantasm, had Gilgamesh been injured.
…
On the red steel arches of the Fuyuki Bridge sat a large, muscular man with fiery red hair. His red cloak billowed in the wind.
"Rider, shouldn't we go somewhere… safer?" a timid voice beside him asked.
They were Waver Velvet, and his Servant, Iskandar, the King of Conquerors.
"Hahaha, my boy, it seems your courage still needs tempering." Iskandar laughed. While his Master lacked bravery, Iskandar, as a king, was a skilled judge of character. He saw potential in Waver, the raw material for a future advisor.
"Boy, as my Master, the first thing you must learn is to trust me. Even if you fell from here, this height is nothing. I can catch you before you hit the ground. You wouldn't be harmed."
"Even if you say so…" Waver began to retort, then stopped, meeting Iskandar's gaze. Despite his boisterous demeanor, Waver had learned, over the past day, to trust the King of Conquerors.
He grumbled under his breath, but instead of clinging to the steel arch, he straightened up and sat astride it.
Iskandar smiled. He knew his Master wouldn't be an ordinary person.
He looked towards the port. There, three heroes from different eras were engaged in a fierce battle of skill, a display of power beyond the comprehension of modern man, a glimpse into a bygone era of legends and myths. The sight filled him with excitement.
Every Servant summoned by the Grail had a wish they desired to fulfill. Iskandar was no exception. But his wish was a grand one, one he couldn't achieve alone. He needed the help of these heroes, these legends from across time.
"I thought Lancer and Saber's skills were unparalleled, but to think… such swordsmanship exists in this world…" he murmured, observing Ailin holding his own against both of them. He wasn't confident he could defeat either Lancer or Saber, not without using his own trump cards. But he didn't shy away from acknowledging their strength. As a king, the ability to command those stronger than himself was a mark of true leadership.
…
Through his sniper scope, Kiritsugu Emiya observed the battle at the port. His eyesight, however, wasn't keen enough to discern the details of their fight. He'd have to use his "Time Alter" magecraft to accelerate his perception of time, to clearly see their movements.
But even without seeing the specifics, the glimpses he caught of the three Servants were enough to tell him that the Servant who had killed Maiya was stronger than even Saber. This solidified his resolve. To win this war, he'd have to rely on his own skill and eliminate the other Masters one by one. Saber's strength alone wouldn't be enough to secure victory. The Berserker-like Servant, and the Archer he'd fought, were far too powerful for her.
He looked away from Irisviel, suppressing the urge to test the defensive barrier surrounding her. He scanned the area around the port, searching for the Masters of Lancer and Berserker. If he could eliminate one of them tonight, it would reduce the competition. He also hoped to contact Berserker's Master, to propose an alliance against Archer.
Compared to a proper magus like Kayneth, Kariya Matou was a mere amateur. And having lived in the mundane world, his sense of danger was underdeveloped. Even Ailin's attempt to conceal him in an inconspicuous location was futile against a seasoned assassin like Kiritsugu.
He quickly located Kariya. Unable to find Lancer's Master after a thorough scan of the area, Kiritsugu packed up his sniper rifle and jumped through an open window into a nearby building. It was one of the safehouses he'd prepared for Maiya Hisau. It was a bitter irony that he was now using it himself. Maiya was gone, lost to him forever.
He concealed the rifle and took the elevator to the underground parking garage. He picked a random car, hotwired it, and drove away.
…
"Berserker seems to be enjoying himself…" As Ailin's Master, Kariya, thanks to their high compatibility, could sense flickers of his Servant's emotions through their magical link. And right now, he sensed excitement.
Ailin was indeed exhilarated. Within his Unlimited Blade Works were Zanpakutō forged from the "sword element" of both Excalibur and Diarmuid's twin spears. With each clash against the genuine articles, his understanding of their abilities deepened. He felt that once his analysis was complete, he could fully integrate their powers into his own Zanpakutō, creating blades that rivaled, perhaps even surpassed, the originals. These enhanced blades would, in turn, amplify his own power. How could he not be excited?
Having gained valuable experience from Artoria and Diarmuid, Ailin now looked forward to his next encounter with Gilgamesh. In this world, his Unlimited Blade Works couldn't automatically collect the "sword element" of all past, present, and future blades. He knew this was because he hadn't yet reached the Root of this world, hadn't connected his Unlimited Blade Works to it. Once he did, he could collect the "sword element" of every blade in this world, just as he had in the Soul Society.
Until then, he'd have to rely on his own observations, collecting the "sword element" of any blade he encountered, storing it within Unlimited Blade Works, waiting to be forged.
And in this Grail War, who possessed more "swords" than Gilgamesh, the King of Heroes?
This was why, during their previous clash, Ailin hadn't relied on his swordsmanship. He'd used his Unlimited Blade Works to goad Gilgamesh into unleashing more Noble Phantasms, to collect more "swords." Unfortunately, their fight had been interrupted by Maiya. If not for her interference, he wouldn't be here now, fighting Artoria and Diarmuid. He'd be in his inner world, forging the "swords" he'd copied from Gilgamesh.
BOOM!
Having completed his analysis of Excalibur and Diarmuid's twin spears, Ailin unleashed the full power of his dual-blades as he pressed his attack against Artoria and Diarmuid.
While he hadn't specifically trained in dual wielding, his Unlimited Blade Works contained the skills of many dual-wielding masters, such as Shunsui Kyōraku and Jūshirō Ukitake. By synchronizing with their Zanpakutō, he'd absorbed their mastery of dual wielding. Combined with his technique of amplifying his slashes, he single-handedly suppressed both Artoria and Diarmuid.
…
As Ailin's fierce battle continued, Kiritsugu Emiya arrived at the building where Kariya Matou was hiding. Without hesitation, he took the elevator and navigated the corridors until he reached Kariya.
"Kariya Matou, Master of Berserker," Kiritsugu said. "Hello."
"Who's there?" Kariya jumped, startled by the voice behind him. He turned to see a middle-aged man in a black suit whose face was covered in stubble.
Despite the man's disheveled appearance, his eyes were sharp, focused. It was a look Kariya recognized, a look he'd seen in his own eyes the day he'd resolved to save Sakura. It was the look of a man who had made a difficult decision.
Seeing Kariya's reaction, Kiritsugu's confidence in his plan increased. He was certain that once their alliance was formed, victory in the Grail War would be his.