The violet sparks that suddenly burst into the air were glaringly vivid against the darkness of the night.
Tohsaka Rin and the others, who were watching from the sidelines, had still been reeling from the suffocating pressure of the overwhelming demonic power radiating from Ren Kuroda's body when the crackling, popping thunder abruptly stole their attention once again.
"By the fury of skin-scorching divine lightning—By the authority of the Thunder Star, Rokuzon—Move like Thunder—Rokuzon!"
Many people believe that Rokuzon, one of the Seven Stars, is merely a scholarly star symbolizing official salary and status. In truth, although Rokuzon is indeed classified as a literary star, the meaning it carries is far more severe.
Rokuzon signifies this:Debts must be repaid.Losses must be compensated.Kills must be answered with blood.
The credit lies with me—so how you repay it is for me to decide.
An eye for an eye. A tooth for a tooth.That kind of straightforward, unrestrained savagery is what truly befits thunder.
As one of the three techniques of the advanced "Wind, Forest, Fire, and Mountain", Move Like Thunder—much like Swift as the Wind—was a technique focused almost entirely on speed.
The wind was already fast.
But thunder was faster.
Unlike the ever-changing, all-pervasive nature of wind, thunder had no twists or subtleties to it. It was about raw, brutal destruction—simple and direct.
Such was the might of thunder: those who touched it were shattered.
As an advanced evolution of the Wind–Forest–Fire–Mountain style, Move Like Thunder surpassed Swift as the Wind in speed, exceeded Ravage Like Fire in destructive power, and could be described as a reinforced fusion of both techniques.
When Ranserotto had drawn The Undying Radiance of the Lake, his parameters had already risen another tier—his original A+ Agility had climbed to at least A++.
Yet the moment lightning erupted from Ren Kuroda's body and he calmly stepped forward, neither Ranserotto nor anyone else present could perceive anything more than a single flash of thunder slicing through the night.
By the time they realized what had happened—
Ren Kuroda was already standing behind Ranserotto.
The Undying Radiance of the Lake possessed the trait of never deteriorating. Even Ren Kuroda could not destroy it. But no assassin worth their name would ever choose to attack an opponent's weapon directly.
The rumble of thunder still echoed through the air. Faint afterimages of lightning lingered in the darkness. As Ren Kuroda slid his Nichirin blade back into its sheath—
Click.
Blood exploded from Ranserotto's chest.
The armor that constantly emitted black mist around Ranserotto's body was itself a Noble Phantasm, known as "Not for One's Own Glory." It was a B-rank artifact that concealed the user's true parameters.
While it did little to enhance defense directly, the thick armor itself still provided considerable protection.
Even so, Ren Kuroda's slash had pierced straight through it, leaving Ranserotto grievously wounded.
The crackling arcs of lightning still dancing across the shattered armor were the clearest proof.
With the armor broken and Not for One's Own Glory rendered inactive, Ranserotto's face beneath the helm was exposed to everyone present.
Staring at the face revealed beneath—handsome enough to rival his own—Ren Kuroda couldn't help but sigh inwardly.
No wonder King Arutā got cuckolded… and Queen Ginevia ran off with this guy.
"Sorry about that," Ren Kuroda said calmly."It's my first time using this technique, so I wasn't fully used to the speed yet. I didn't control it very well."
He raised his blade slightly, his gaze sharp.
"This time, I'll cut your throat cleanly and make sure you exit properly."
Earlier, when he had unleashed Move Like Thunder, Ren Kuroda had indeed aimed for Ranserotto's throat and other vital points.
But just as he said, the speed of Move Like Thunder was so extreme that even he couldn't fully master it on his first use.
Of course, that wasn't the only reason.
At the very instant the attack was about to land, Ranserotto had twisted his body just enough—barely—to avoid a fatal hit.
After all, he was still a Heroic Spirit possessing Eternal Arms Mastery and an Agility parameter exceeding A+. When Ren Kuroda struck, Ranserotto had managed to catch the faintest trace of an afterimage.
But that was all.
He could perceive it—vaguely—but his body simply couldn't keep up.
And so, he was instantly gravely wounded.
"Did Assassin just release a Noble Phantasm…?" Rin muttered in disbelief."All I saw was a flash of lightning—and Berserker, whose presence had grown terrifying just moments ago, was instantly crushed!"
Even Ranserotto, with his masterful skill, had only barely perceived Ren Kuroda's movement. For everyone else, the experience was even more overwhelming.
Faced with Rin's question, Archer—Emiya—could only wear a helpless expression.
He had no idea how to answer.
Not just Rin or Emiya Shirou—even as an Archer with the Mind's Eye skill, what he'd seen hadn't been much more than what Ranserotto had perceived.
Still, there was one thing Archer could say with certainty.
What Assassin had just used was absolutely not a Noble Phantasm.
To unleash the full power of a Noble Phantasm, one had to invoke its true name—and Ren Kuroda had done no such thing. What he'd shouted sounded far more like the name of a combat technique.
Of course, some Heroic Spirits eventually had their techniques crystallized into Noble Phantasms due to their sheer power.
But Assassin had already displayed far more than just that absurd lightning speed.
His earlier wind-based slashes had been just as outrageous.
If all of those were Noble Phantasms, then what exactly was the long blade he used earlier to block Knight of Owner supposed to be?
In Rin and the others' eyes, Berserker—whose strength was already off the charts—had been taken down in a single strike while empowered by Madness Enhancement and a Noble Phantasm.
Not being shocked was simply impossible.
And the sheer magical energy Ren Kuroda had emitted earlier had left them deeply unsettled—it was far beyond what an Assassin should possess.
But what shocked them even more was this—
After grievously wounding Ranserotto, Ren Kuroda's magical energy surged once again, even stronger than before, as he assumed the exact same stance as earlier.
"No way!That kind of absurd, instant-activation technique—and he can use it twice in such a short time?! That's completely unfair!" Rin shouted.
"And judging from the mana fluctuations earlier, that move should consume a huge amount of magical energy! Can Assassin really spam it like this?! Does he have infinite mana or something?!"
Watching Ren Kuroda once again prepare Move Like Thunder, Rin was practically screaming.
But no one could blame her.
Even Archer felt that this Assassin was utterly unreasonable.
Normally, the stronger an ability or Noble Phantasm was, the greater its restrictions and cost.
Yet Assassin had just unleashed something that powerful, looked completely unfazed—and was about to do it again.
How was anyone else supposed to fight like that?
To be honest, Archer couldn't help imagining—
If he were the one facing Assassin, could he even deploy Rho Aias before being cleaved in half?
Ranserotto, with A+ Agility, couldn't even react properly.
If it were him, Archer suspected he'd be dead before finishing a single projection.
And after witnessing that technique, Rin and Archer finally understood why this man had been summoned as an Assassin.
Concealment and ambush were methods for low-tier killers.
Ren Kuroda's assassination style was this—
Even if he charged straight at you from the front, you still couldn't stop him from killing you.
"This Assassin is far too dangerous to oppose," Rin said quietly."Archer, let's work with them. We helped them earlier, and now they helped us. Their Master seems reasonable enough."
After witnessing Ren Kuroda's overwhelming strength firsthand, Rin found it genuinely difficult to view him as an enemy.
Besides, she had always thought Archer was… well, a bit underpowered.
Relying on their own strength alone to defeat all the Heroic Spirits in the Holy Grail War felt unrealistic.
"Rin," Archer replied calmly,"don't forget—you already invited that kid and Saber, then Sakura Matou and Rider. If you add Assassin and his Master, that makes four Servant–Master pairs."
He paused.
"This Grail War only allows two winning factions.Which means, eventually… you'll still have to fight each other."
Because the Fourth Holy Grail War had ended without a victor, the Grail had generously allowed two winners this time.
Even so, there still weren't enough wishes to go around.
"I don't really care about wishes," Rin said softly."I joined this war to prove myself to my late father."
She clenched her fist.
"In the end, both my parents died because of the Grail. I want to personally bring all of this to an end."
She looked toward the battlefield.
"We can promise Assassin a wish. As for the other… we'll give it to Sakura and Emiya-kun."
Unfortunately, while Rin's calculations were running perfectly—
Something completely unexpected happened on the battlefield.
Ranserotto was grievously wounded. One more strike would have sent the Knight of the Lake out of the war.
But just as Ren Kuroda was about to finish it—
Saber suddenly raised the Sword of Promised Victory and stepped in front of him.
"Saber," Ren Kuroda said coldly,"what do you think you're doing?"
"We're on the same blue faction. Berserker belongs to the red faction."
His eyes narrowed.
"Should I take this as you trying to stop me… or helping Berserker?"
Staring at the suddenly intervening ahoge king, Ren Kuroda's expression darkened.
Truth be told, even without asking—
Given his understanding of Saber,
He already had a pretty good idea of what she was about to do.