Her grip tightened on Excalibur. Even with all this, even after losing half of his body, Berserker still wouldn't stop.
She barely noticed Archer landing beside Rin, his red cloak billowing as he straightened from his attack.
"Took you long enough," Rin muttered, arms crossed.
Archer didn't even glance at her. His sharp eyes remained locked onto Berserker's slowly regenerating form. "I was waiting for the right moment."
Shirō exhaled sharply, sweat trailing down her temple. But something still gnawed at her, something deeper than just the fight.
She turned to Illya.
"You called me 'Big Brother' earlier," she said, voice tight. "Or was it 'Big Sister' now?"
Illya's expression twisted into something unreadable—anger, bitterness, and something else.
Shirō pressed forward. "Why? Why are you so fixated on me? Why are you the one who wants to kill me so badly?"
Illya's fists clenched, her nails digging into her palms as she trembled with rage. "You don't know?"
Shirō frowned. "No. I don't—"
"Don't act like you don't know!" Illya's voice was sharp, cutting through the battlefield like a knife.
Shirō flinched. "Know what?"
Illya's crimson eyes burned with fury, her voice shaking with something far deeper than just hatred.
"Father left me and my mother because of you!"
Shirō's breath caught.
"Father...?"
Who—
Who was she talking about?
"Who's your father?" Shirō asked, hesitant.
Illya's disgusted expression deepened, as if the very question was an insult. "Kiritsugu Emiya. Who else do you think?"
Shirō froze.
Everything around her dulled, sounds fading into a distant hum. The weight of Illya's words crushed her, as if her entire existence had just been upended.
Kiritsugu... Emiya?
The name was foreign, yet familiar—like a ghost of a memory she had never known to have.
Her fingers slackened.
Excalibur slipped from her grasp, its golden light flickering before vanishing entirely.
"You're... my sister?" Shirō's voice barely came out as a whisper.
Illya scowled. "Unfortunately. But not by blood, obviously. Which is why I must kill you—"
A voice interrupted.
"I think you are gravely mistaken, girl."
Archer stepped forward, arms crossed, his eyes sharp with something cold and knowing.
Illya turned to him, irritated. "Oh? And what do you know, Faker?"
Archer ignored the insult, his gaze unwavering. "I did some research on Kiritsugu Emiya." He spoke casually, as if he was merely recounting a mundane fact. "And I discovered something interesting."
Shirō and Illya both remained silent, their eyes locked on him.
"He was a Master in the last Holy Grail War. His Servant was none other than Saber," Archer said, tilting his head toward Shirō. "He won the war."
Illya's expression darkened. "Lies."
Archer continued as if he hadn't heard her. "But the Grail was corrupted. Tainted. Kiritsugu realized that granting its wish would be a mistake, and so, he destroyed it."
Illya clenched her jaw. "No."
"He was then banished by your family—the Einzberns. Your family. They never allowed him to return. He never abandoned you."
Silence.
Shirō could see it—the way Illya's entire body tensed, how her breathing became uneven, the flicker of something in her crimson eyes.
Doubt.
"No," she hissed, shaking her head. "You're lying—"
"Why would I?" Archer shrugged, his expression unreadable. "I have no reason to deceive you."
Shirō swallowed, her mind racing. It made sense. Everything. Kiritsugu Emiya. The Grail War. The corruption. His banishment.
Illya's hatred.
She had spent her whole life believing that Kiritsugu had chosen to leave her, to abandon her and her mother. That Shirō was the reason.
But it was never true.
Kiritsugu had been cast aside. He never had a choice.
Illya's hands trembled.
Shirō opened her mouth, wanting to say something—anything.
But Illya stepped back.
Without another word, she raised her hand.
A shimmer of mana surrounded her, and in the next instant—
She was gone.
Berserker vanished alongside her, his hulking form dissolving into mist.
The battlefield was silent.
For the first time in what felt like hours, Shirō exhaled, shoulders sagging.
Rin clicked her tongue. "Well. That was something."
Archer hummed. "Indeed."
Shirō stared at the empty space where Illya had been, her mind still reeling.
She wasn't sure what she felt.
Relief?
Confusion?
Something else entirely?
But she did know one thing.
This wasn't over.