Ahad, leaning on his staff, led Kiritsugu Emiya—whose heart was filled with doubt and resistance—down the castle's cold, interminable corridors.
They finally stopped before an ornate door carved with ice crystals and runes.
"She is one of our finest homunculi, the perfect inheritor of the 'Holy Maiden of Winter,' Justeaze's bloodline and visage.
"Her name is Irisviel von Einzbern."
With that, Ahad pushed open the heavy door.
The room was arranged more warmly than the rest of the castle. Flames danced in the fireplace, pushing back a measure of the chill.
Even so, the scene inside made both men at the threshold freeze, pupils constricting in shock.
A woman with long hair like flowing silver, skin pale as snow, and features so exquisite they hardly seemed of this world, was nestled lightly in a man's arms.
The woman—Irisviel—wore a shy, blushing expression as she rested her head on the man's shoulder.
And the man, his back to the door, was none other than Rei Ao, who by rights should have been in Fuyuki City.
Perhaps he heard the door open. Rei Ao slowly loosened his embrace. Irisviel lifted her head, a faint mist still clinging to those beautiful, ruby-like eyes.
She looked toward the doorway and saw a livid Ahad and Kiritsugu Emiya, whose gaze was as sharp as a hawk's.
Rei Ao turned around. His calm, sea-blue eyes swept over the two men as if their appearance were no surprise at all. His gaze paused on Kiritsugu for a beat, as though seeing through the justice-warped soul within him and the dubious origin of the Command Seals on the back of his hand, then returned to Ahad.
The corner of his mouth lifted in a faint, slightly mocking arc. "Ahad-sama, dropping in uninvited. How discourteous of you."
His clear voice shattered the frozen air of the room.
"It seems I've come at the wrong time—or perhaps… at just the right one?" Ahad's face was so dark it looked ready to drip ink. He slammed his staff against the floor with a dull thud. "Who are you?! Why are you in the heart of my Einzbern castle?! And what have you done to Irisviel?!"
Irisviel instinctively edged closer to Rei Ao. That subtle motion made Ahad falter for a moment.
Rei Ao didn't answer Ahad directly. Instead, his eyes returned to Kiritsugu. "Kiritsugu Emiya, a pitiable man chasing the empty ideal of 'world peace.'" His tone was mild, but carried the weight of someone who understood everything.
Kiritsugu's heart tightened; his hand clenched on reflex.
"As for why I'm here…" Rei Ao gently patted Irisviel's shoulder, a silent reassurance, then said to Ahad, "I came to tell a purehearted girl the truths you've hidden from her.
"For example: she is not merely a vessel for the Grail. She has her own freedom and future—neither of which should be taken from her.
"And another: the tainted Grail you seek can realize neither the Third Magic nor any wish for world peace. It brings only calamity—the advent of the Evil of This World."
"Absurd!" Ahad barked, cold mana gathering around him. "A millennium of Einzbern pursuit will not be slandered by some nameless interloper! Irisviel was born for the Grail. That is her mission!"
"Mission?" Rei Ao let out a soft laugh, brimming with pity. "To mold a thinking, feeling life into a mere 'object' for the sake of your nebulous dream—that is the Einzberns' 'mission'? How sad. How foolish."
His words pierced the pillars of faith Ahad had leaned on for centuries.
"And you, Kiritsugu Emiya," Rei Ao continued, turning to the shadow-eyed magus-killer. "You think arithmetic like 'sacrifice the few to save the many' will lead you to peace? Even if you win, the tainted Grail will only twist your wish, realizing your 'peace' in the most cruel, despairing way. What you chase has been a mirage from the start."
Kiritsugu's breath hitched. Rei Ao's words tugged at the deepest fears and doubts in his heart—yet years of experience kept him from wavering easily. "Who are you to judge any of this?" he said coldly. "On what basis do you make these claims?"
"Who I am doesn't matter," Rei Ao replied evenly. "What matters is that I've seen the truth, while you keep lying to yourselves."
He took Irisviel's hand—natural, intimate. She didn't resist; instead, she gripped him back tightly, as if she'd found her only anchor.
"Irisviel, I'm taking you out of this cage today." His voice was quiet, utterly assured.
"Impudence!" Ahad finally exploded, a storm of power surging through the room as the castle's bounded field roared to life at his command.
Kiritsugu, too, shifted instinctively into combat readiness. Confusion churned within him, but Einzbern support was a crucial piece of his plan. He couldn't let a stranger wreck it in front of him.
Despite the hostility of the two men and the crushing pressure of the castle's ward, Rei Ao's expression didn't change. He merely lifted his gaze a fraction. In those blue-green eyes, it was as if star-rivers turned and laws were born and died.
"I said I'm taking her with me."
The instant the words fell, an intangible pressure—beyond anything that could be called magecraft—spread out from him in utter silence.
"—!!"
Ahad's frigid mana met a blazing sun and vanished in an instant. The castle's bounded field gave a strained, dying wail; its light flickered violently, then went out.
Kiritsugu felt as though he'd been cast into an endless abyssal sea. The air around him turned thick and heavy; lifting even a finger became almost impossible, and the flow of prana in his body nearly stalled.
What power is this?! It wasn't magecraft at all—more like the world itself was rejecting them, suppressing them.
For the first time, stark terror washed over Ahad's face. Kiritsugu's eyes, too, were wide with disbelief. Before this force, they were as small as ants.