Ayaka could not tell whether it was her own brain raising these doubts, or whether it was the tattoos inscribed on her arms and the curse the “white woman” had built into them making it do so. The noise of the tattoos had grown so loud it had paralyzed her basic powers of judgment.
They seemed to be cheering, or screaming, as if to welcome something that was about to appear. Then, the next instant—
Corporeal “death” swept down on the opera house stage.
But not on Ayaka; behind the mage who was to have been her executioner.
“Emerge from the ring of restraint, O Guardian of the... scales...?”
How long had “it” been there? To Ayaka’s eyes, at least, it looked as if it had materialized out of thin air.
A petite human figure swathed in shadow-black robes. Ayaka could see that its whole body was covered in black cloth, but she could not make out the face. All she remembered clearly was the moment a weirdly long arm stretched through a gap in the robes, and came to rest on the chest of its victim.
As soon as she saw that, Ayaka knew. Knew that the situation she now found herself in no longer belonged to the world she knew — it was on the other side of the world’s shadows, invisible to the eyes of those who lead ordinary human lives. The moment she realized that, a diminutive human figure appeared in her field of view.
A young girl wearing a red hood.
Whether she was actually a phantom or a real image, Ayaka in her confusion could not tell. Why here? This building doesn’t even have an... elevator. The “thing” that had appeared on the opera house stage looked as if it was standing on the corpse. “It” faced Ayaka with an innocent smile.
Even before she realized what that smile meant, dread ran through Ayaka from head to toe. It was hard to say which came first, the almost audible shiver than ran down Ayaka’s spine, or the black-robed intruder crushing the heart-like thing that appeared in its long hand.
“Gah... bah...?”
The mage vomited blood, still not comprehending what had happened to his body. It was doubtful if he even realized who had killed him.
Ayaka was terrified of both the black-robed figure and the girl in red, but at the same time she was thinking detached, somehow impersonal thoughts, like “Oh, I’d hate it if they got the wrong idea and thought I killed him.” She probably knew instinctively that she would be crushed by fear if she did not.
The moment the mage ceased to move, the magical cord that had been binding Ayaka from head to toe crumbled away.

Fate/Strange Fake: Volume 2, Part 2 ("Day 0, Midnight")