Having parted ways with Ray, the two girls now stood before Lucas Forst. They had already predicted that it would eventually come to this.
That was precisely why they had urged Ray to go on ahead. They were determined to stop him right here, even if their opponent was one of the Seven Grand Sorcerers.
That was their resolve.
"Ariane... buy me some time."
"Surely you don't mean—Amelia. Are you already planning to use that?"
"We can't afford to hold back anymore. You can tell, can't you? Look at that overwhelming material field."
"...Understood. I shall hold him back."
In that instant, Ariane immediately activated her Origin Magic, Ogrification.
Red-black codes surged across her slender, supple limbs, becoming visible as they raced along her skin.
Ariane kicked off the ground with all her might. Closing the distance at top speed from the start, she attempted to drive a fist into Lucas Forst's solar plexus, but...
"Fast. And the power is impeccable. Truly wonderful."
Ariane was struck with amazement the moment she heard those words.
The fist she had thrown, believing it was a guaranteed hit, had been evaded with incredible ease. However, she was not one to give up so easily.
Through her training with Ray, she had grown accustomed to fighting opponents far stronger than herself. If she were to give up here, everything would be over.
—I won't break from something of this level!
Ariane pressed her attack relentlessly, determined not to give Lucas the leisure to activate a Secret Sword.
She had to keep him from using a Secret Sword. Furthermore, she needed to buy time until Amelia could activate her Butterfly Effect.
Driven by that singular focus, Ariane pushed her body's performance to its absolute limits as she faced Lucas.
However, her opponent was not a Seven Grand Sorcerer for show. Ariane was using Origin Magic—a technique reached only by mastering the depths of inside codes—and yet he parried her attacks with casual composure.
"It should be about time..."
The moment he muttered those words under his breath, Lucas vanished from her sight.
"—Amelia!"
Realizing she couldn't catch him in time, Ariane shouted toward Amelia behind her.
Lucas had been watching for an opportunity with predatory intent. He was aiming for the exact moment Amelia activated her Butterfly Effect—the instant where her guard would be at its weakest.
The slight rigidity just before activation. In that split second, a sorcerer cannot switch to other magics. It was a momentary clash that exploited the briefest lapse in Ariane's focus.
"—It’s okay. The causality has already been established."
<<Prima Materia = Encoding = Material Code>>
<<Material Code = Decoding>>
<<Material Code = Processing = Aitia = Constitutive Qualia = Formal Qualia = Subjective Qualia = Final Qualia>>
<<Embodiment = Causality>>
"—Butterfly Effect."
Just before Lucas reached her, a massive swarm of crimson butterflies erupted from Amelia’s back. It was like a flaming dance. What scattered through the air was deep-red Prima Materia.
Lucas had completely read the construction of Amelia's magic formula. That was why his timing had been so precise. He had intended for his strike to be a certain hit.
He had predicted that he could surely take her down here.
And yet, an infinite swarm of crimson butterflies manifested before him. The butterflies overflowing in a spiral were the undeniable proof that Butterfly Effect had been activated.
Through this sequence of offense and defense, Lucas realized he had been lured.
At the very last second, Amelia had accelerated her code construction all at once. Normally, a sorcerer does not vary the speed at which their code runs; the standard theory is to run the code at maximum speed from start to finish.
Even the Seven Grand Sorcerers were no exception to that rule. But Amelia had used the speed of her own code construction as a decoy.
It was an achievement she had gained through her training with Lise. Amelia’s code construction technique was already approaching the level of the Seven Grand Sorcerers.
"...I suppose it can't be helped."
Lucas’s feet did not stop. Since the Butterfly Effect had been activated, he simply had to fight with that taken into account.
He sheathed his sword. Then, he unleashed a Secret Sword toward Amelia without hesitation.
"Eighth Secret Sword—Afterglow Gloom."
A dazzling light dominated the space, and the world suddenly blacked out.
In that world of sealed vision, Lucas slipped into Amelia's personal space and delivered a single flash. He was certain the blade had struck Amelia directly, but...
"It’s useless. The causality of this world has already been established."
Amelia stood calmly as even more crimson butterflies overflowed around her.
She had already established the causality. It produced the result that "Lucas's attacks will not hit." Because of that, his Secret Sword, which should have been a guaranteed hit, had its causality warped.
It was a certain hit, and yet it failed to reach her. As if the blade were intentionally avoiding her of its own accord, it distorted just before reaching her body.
Lucas put some distance between them, sheathing his sword again. He pressured the two girls with a piercing, steady gaze.
—Butterfly Effect. As expected, it is an incredibly troublesome ability. Now that it has been activated, I no longer have a way to break through it. However, the problem is likely... time.
Lucas Forst was not merely a man of high combat ability. His intellect was equally sharp when it came to battle.
The previous clash had been a test to measure the performance of Amelia’s Butterfly Effect. He hadn't unleashed the Secret Sword for nothing.
He now understood that even a Secret Sword was powerless before those butterflies that governed causality.
If Amelia were using Butterfly Effect for offense, he might still have a way through. He could simply cut her down with overwhelming speed and his Secret Sword while absorbing some damage himself.
However, Amelia understood the nature of her magic. She knew it was best to construct the Butterfly Effect for defense during combat.
Absolute defense.
Not a physical barrier, but a perfect defense that dominated causality itself. It was something that even Lucas, the Absolute Blade Sorcerer, could not break through.
The connection of causality. Right now, the causality of this space was entirely under Amelia's control.
"...Phew."
Exhaling sharply, Lucas shifted his target to Ariane.
The establishment of causality could likely only be tied to one target at a time. Currently, attacks would not hit Amelia Rose.
Therefore, he would simply target Ariane Algren. But even that attack failed to reach its mark.
Gazing at his sword as it sliced through empty air, Lucas muttered quietly.
"Can causality be activated in two places simultaneously? No, that would be far too powerful. The likely hypothesis is—"
Amelia could not activate causality for two people simultaneously, but she could switch the target instantaneously.
If there were multiple opponents, this tactic would not work, but currently, Lucas was alone. Against a single foe, she could theoretically fix the cause and manipulate the result for whoever he targeted.
His deduction was right on the mark.
With a sharp whoosh, Lucas swung his sword and took an upper-level stance.
"Just as I suspected. From here on—it's a contest of endurance."
A war of attrition.
Lucas’s decision to move toward a stalemate was exactly what Amelia had expected. She knew that if the battle developed this way, Lucas Forst would inevitably try to outlast them.
They were reading each other. Every single move in this clash had meaning.
Lucas analyzed the situation calmly, and Amelia had predicted his every move. Through this series of exchanges, Lucas had reached a certainty.
He had found the weakness of the Butterfly Effect.
The sole weakness—its duration.
Though her limit had improved, Amelia could not maintain the Butterfly Effect for long.
The battle from here on would not just be about Amelia. While the defense relied on her, she would not be able to weather the storm alone.
It would not be an exaggeration to say that the outcome now rested on Ariane's shoulders.
"Ariane. This is as far as I can go. I won't let a single attack hit you. So, fight to your heart's content."
"Yes. I understand."
Blood had already begun to trickle from Amelia's nose—a sign that her magic area was nearing an overheat.
However, Ariane showed no sign of worry. Holding fast to the fact that she had been entrusted with this task, she challenged the Absolute Blade Sorcerer alone.
The time limit was narrow. If Ariane could settle the score within that window, their victory in the tournament would be all but guaranteed.
It was a race against time for both sides.
Would Ariane defeat Lucas before the Butterfly Effect was released? Or would Lucas be able to endure until Amelia hit her limit?
The final battle was entrusted to Ariane.
"—I'm going now, Amelia."
Ariane ran new codes, layering them multiple times.
<<Prima Materia = Encoding = Material Code>>
<<Material Code = Decoding>>
<<Material Code = Processing = Inside Code = Manipulation>>
<<Embodiment = Phenomenon>>
"—Impulse."
With a series of sharp crackles, Ariane clad her body in violet-black lightning.
The electricity spreading around her was incomparable to the Origin Magic she had used before. The density of the Prima Materia was overwhelming. Furthermore, her entire material field was being converted into those violet-black bolts.
Once more, she lowered her center of gravity and faced Lucas.
"Now then, please dance with me."
The Valkyrie of Lightning shall dance upon the battlefield—