Shirou's presence was completely different from moments before.
A powerful surge of energy gathered around his left hand like a rapidly spinning vortex.
His Mana was forcibly compressed to the absolute limit, so dense and scorching that its color was visible to the naked eye.
"That is..."
Saber Alter stared at the boy without the slightest reaction, feeling through her skin a dragon's Mana utterly unlike her own.
That twilight-colored Mana did not come from the "Red Dragon Emperor's Boosted Gear." It was a fantastical color born from Shirou refining his own Mana to the utmost extreme.
"I see. So that is the real reason you are called Arthur... the 'Twilight Dragon' of another Britannia."
Then she once again lowered the pitch-black demonic sword to her waist, took up the stance to release her Noble Phantasm, and declared calmly,
"A contest of firepower...? Very well."
The corrupted Holy Sword erupted once more with a destructive aurora.
The crimson gauntlet became wrapped in twilight-colored waves of Mana.
"Kneel before me, Shirou! Ex.."
"Wake up, Saber! Dragon..."
The greatest eruption of Mana that night burst forth.
Pitch-black darkness and twilight shattered across heaven and earth, carrying the roars of two dragons beyond human understanding.
The two tyrants who had once ruled Britannia.
The girl swung her black Holy Sword with the majesty of a king, while the boy raised the dragon's claw and fired a twilight magic bullet.
"...calibur Morgan!!!"
"...Shot!!!"
A head-on collision of dragon breath.
The two vast torrents of power slammed into each other and locked in stalemate, whipping the entire space into a violent storm.
The impact shook the fabricated landscape created by the Grand Illusionist (Merlin), and fierce distortions of time and space spread through the false Unlimited Blade Works.
"This is getting a little bad..."
Lady Avalon frowned slightly.
Even while maintaining Spirit Form, she could tell that Shirou was losing ground in his Noble Phantasm clash with Saber.
Even after boosting his power fivefold through the dragon gauntlet, the Mana shell Shirou fired still could not reach the black swordswoman.
On the other hand, Saber Alter's pillar of aurora was steadily eating away at his attack.
She really is strong, Saber...
Shirou sighed inwardly.
Saber, corrupted and empowered by the Holy Grail, was a Heroic Spirit who had pushed the combat style of Noble Phantasm release to its absolute extreme.
In a straight Noble Phantasm clash, even Gilgamesh, the King of Heroes famed for his overwhelming firepower, probably could not gain the upper hand against her.
But...
Saying I'd fight you head-on in a contest of firepower was a lie. There's no way I'd throw away my own advantage!
I'll win. But I'll do it my way.
"Time Alter Hexagon Accel!"
Shirou shouted out a realm of acceleration that even EMIYA, the Heroic Spirit who created the technique, had never reached and never dared attempt.
"Gah...!!"
Shirou lurched forward and coughed up a mouthful of blood.
He had already prepared himself for the backlash, but the shock hitting every cell in his body still nearly killed him on the spot.
With his internal time accelerated to that extent, Shirou did not even have room left to think.
So this is the world of sixfold speed.
There was no way a human body should be able to endure side effects like this, but...
Lady Avalon once endured side effects a million times worse than this in my place!
Compared to what she suffered, what does this little bit of pain amount to!?
Shirou clenched his teeth hard.
As if walking on a planet with gravity a million times stronger, he forced out his first step.
Shirou vanished.
In the next instant, he appeared in front of Saber Alter.
"Blade!!"
The "Boosted Gearr" gave its voice prompt, and a shining silver blade extended from its tip.
"...A futile resistance."
The instant Shirou slashed, Saber Alter drew her sword with one hand and blocked.
Even with all his abilities multiplied fivefold, Shirou's Strength still did not match Saber Alter's, so one hand should have been enough.
And yet, just as she casually prepared to knock him away, a chilling sense of danger rose in the girl's heart.
Saber Alter switched to a two-handed grip without hesitation.
Clang.
The silver sword and the black sword crashed together, spraying sparks and ripples of Mana as a shrill metallic cry rang out.
At the moment of impact, Saber Alter sensed the truth of the blade extending from Shirou's left arm. She stepped back half a pace and released the pressure of the deadlock.
Surprise showed on her face.
"This is... a dragon-slaying Holy Sword...?"
Shirou nodded.
"Yeah. It seems to be the Holy Sword called Ascalon."
Hidden within the Red Dragon Gauntlet, completely fused with it, was the famous blade known as the Dragon Slayer.
"Ascalon." It was also the reason Shirou had been able to project the "Boosted Gear."
Swinging the dragon-slaying Holy Sword, Shirou shifted from defense to offense.
Holy Sword and demonic sword traced beautiful arcs as two different dragon auras clashed again and again in the blazing air.
One exchange, then another, then a third.
With the sixfold speed bought at the cost of his life, Shirou was now far faster than Saber.
Every clash left another cut across the girl's pitch-black armor.
Saber Alter's stance was gradually breaking apart. Before that happened completely, though, her Mana armor would likely collapse first.
Shirou drew a deep breath. Good. I'll corner her in one push.
"...Vortigern."
The black King of Knights, driven to the brink, murmured under her breath.
"!!"
Shirou had been ready for it.
Before the roaring black flames could swallow him, he sprang backward and opened the distance.
The boy's evasive movement looked almost like teleportation. The blue Artoria might have been able to keep up, but the black version of her could not pursue him at all.
By the time Saber Alter looked back at Shirou, he had already raised his right arm and begun charging power.
"Dragon Shoot!!"
The twilight-colored dragon breath came roaring in again.
Caught off guard, Saber Alter had no choice but to raise her Inverted Holy Sword and block the magic bullet head-on.
Because he had only gathered Mana for a short time, this shot was far weaker than the last one. Even so, it still sent Saber Alter flying.
"...Ugh!"
It was the first time in her life that she had hit the ground on her back.
The pain and shock from the impact snapped Saber Alter out of her brief daze, and she realized her Reversed Holy Sword was gone.
It had been knocked several meters away while she was blocking the magic bullet.
Saber Alter struggled to prop herself up, but Shirou had no intention of giving her any chance to turn things around.
"Sorry, Saber!"
The red-haired boy leaped over, hesitated for a brief moment, then swung his arm.
His left fist, wrapped in the Red Dragon gauntlet, smashed into that refined, beautiful face. Punching the face of the girl he admired. It felt awful.
"Guh...!"
Saber Alter had barely started to rise before she was struck flying again, tumbling across the ground before crashing down hard.
As she was sent flying, she caught sight of where the Holy Sword had landed from the corner of her eye.
Then, the instant the back of her head hit the ground, she ignored the pain and started crawling toward it.
In truth, Saber Alter had already lost the moment the Holy Sword left her hand.
The outcome had been decided. Shirou had won.
Even so, she still refused to give up.
The once cold and cruel black tyrant now looked like a child throwing a tantrum after losing a fight, stubbornly crawling along the ground.
...Just one more step.
What reflected in the girl's faded eyes no longer seemed to be the Holy Sword (Excalibur), but the Holy Grail itself.
Unlike the silver King of Knights, the black King of Knights had no objection to entrusting her wish to the polluted Greater Grail.
I've come this far. There's no way I can give up now!
Gritting her teeth, the girl reached obsessively for the hilt of the Reversed Holy Sword.
I have to... This time, I absolutely have to...
"Saber, is your wish... to deny your own life?"
"!!"
The boy's voice from behind made her fingers freeze in midair.
Shirou lowered his head and said in disappointment, "You've really let me down..."
"...Ugh."
No matter what Shirou said, Saber Alter still reached for the hilt.
Before she could grab it, Shirou kicked the Holy Sword, which was stuck upside down in the ground, and sent it flying away.
He put tremendous force into the kick. The Holy Sword shot all the way to the edge of the sky.
"....Shirou!!!"
Saber Alter let out a cry of despair and fury.
The red-haired boy stood where he was, silently enduring the hatred in her voice.
A few seconds later, Saber Alter collapsed weakly onto the ground.
Her twisted expression gradually fell quiet.
"Shi...rou..."
Saber turned her head and looked at the red-haired boy.
Even though she had lost the duel, her Mana output was still high.
Even though she had completely lost the will to fight, her Dragon Core was still restoring her Mana and stamina.
If he did not destroy Saber Alter's heart, her Spirit Core, right now, she would recover completely at once.
Do it now, Shirou.
I'm covered in wounds, unable to resist, unable even to stand.
If you don't kill me now, then the one who'll die next will be you.
That was what Saber Alter's cold gaze seemed to say.
But...
The "Red Dragon Emperor's Boosted Gear" wrapped around the boy's left arm was dispelled.
"Why...?"
Saber Alter asked in shock, "Shirou... you're not going to kill me?"
"For a disgraceful Saber like you, letting you live... and making you watch me destroy the Holy Grail with your own eyes is the greatest punishment."
As he said that, Shirou turned his back on her.
"If you still want to fight, then go ahead."
Shirou tilted his head slightly.
"But in your current state, even if you challenged me ten thousand times, you still wouldn't beat me."
"..."
With a peaceful expression, Saber Alter closed her eyes.
...
...
"D-don't come any closer! Don't come any closer!"
The one who had started all of this, Avenger, screamed as she backed away again and again.
Passing by Saber Alter, the unarmed Shirou walked toward her.
Had the overwhelming battle between Shirou and Saber Alter frightened her so badly that she had completely lost her nerve?
The red-haired girl had no fighting spirit left. Her face was full of panic as she tried to get away from Shirou.
Meanwhile, Shirou glared fixedly at the red-haired girl and closed in one step at a time.
To be honest, even he had his doubts.
The more he looked, the more she resembled her. The more he looked, the more certain it felt.
The girl in front of him looked far too much like Baobhan Sith.
Was she really not Baobhan Sith?
If she was Baobhan Sith, then why didn't she remember me?
No. Even if she really was Baobhan Sith... there was no excusing what she had done.
Either way, whether she was or not, she needed to be punished first.
Shirou cracked his knuckles and showed a threatening smile.
"What's wrong? You're not planning to fight? Miss Cernunnos, the 'Cursed God.'"
"Guh... y-you dare look down on me! I'll tear you apart!"
The red-haired girl bit her lip and stretched out five fingers shaped like claws.
"...!"
Shirou's eyes widened, and he instinctively twisted his body aside.
They could not be seen with the naked eye, but through experience and skill, he sensed several invisible slashes rushing toward him.
He dodged four of them. One left a line of blood across his face.
Shirou touched the wound.
...Strings woven from Mana?
Before he had time to think further, even more "strings" came wrapping toward him.
"Die! Ahahaha, serves you right!" the red-haired girl shouted.
A black Holy Sword appeared in Shirou's right hand, and with a casual swing, he cut through every last one of the "strings."
"What? How is that possible...?!"
The girl frantically wove even more slashing threads.
But to Shirou, who had just finished a fierce battle with Saber Alter, attacks on this level felt like nothing more than a breeze brushing past him.
"Why... why don't my attacks work...?"
As Avenger, the will of the Holy Grail itself, every one of her attacks carried an anti-Servant effect, yet she could do nothing to a human Magus.
The red-haired girl kept backing away until her high heel twisted under her foot. With a cry, she fell hard to the ground.
Before she could climb back up, Shirou kicked her flat onto the ground and pinned her down.
"Guh! Get off me, you filthy small fry!"
The red-haired girl struggled wildly, her long legs kicking, her nails clawing at Shirou, until he pressed the "Blades of Chaos" against her throat.
Only then did she finally go still.
"...From here on, all you need to do is answer my question."
Shirou spoke while holding the blade to the red-haired girl's neck.
"I'm asking you. Does the name 'Baobhan Sith' mean anything to you?"
"...Huh?"
Something in the red-haired girl's mind cracked apart.
The name that had come from Shirou's lips gradually brought back her original memories.