Anna.
That name was not the girl's true name.
She only called herself that because she did not want anyone to know her real identity.
This was not something difficult to guess—at least, not for Rozen.
Because, from the very first meeting, Rozen had already been able to "see" the immense divine aura radiating from Anna.
That aura told him—this girl was no ordinary being.
Yet, no hero named Anna connected with the gods existed in the legends Rozen knew.
Since there was no such heroic figure, it was only natural for Rozen to realize: Anna was merely an alias.
After all, since the girl possessed divine aura, she could not possibly be a Heroic Spirit from the future—only one from the Age of Gods.
And among the Heroic Spirits of the Age of Gods, there was no one named Anna whose traits matched her.
With just a little thought, the answer was clear, wasn't it?
From the scale of her divine aura, she could not be a demigod—more likely, she was a genuine, full-fledged goddess.
Yes—Anna was a goddess.
Even more authentic than someone like Jaguar Man.
Once Rozen realized this, guessing Anna's identity was not difficult at all.
"With your fixation on Gorgon, in life you must have been deeply connected to her, no?"
Rozen looked directly at Anna as he spoke.
"And there are only a few goddesses who share such a deep bond with Gorgon."
One was the Greek goddess of wisdom, Athena—the one who cursed Medusa and turned her into a monster.
One was the eldest of the Gorgon sisters, Stheno—the goddess who embodied the completed concept of an 'idol.'
Another was the second sister, Euryale—Stheno's twin, sharing the same origin and almost identical in nature.
And then, there was the youngest of the Gorgon sisters, the incomplete goddess who bore the Mystic Eyes of Petrification—the famous serpent-haired monster, Medusa.
These four goddesses were the only ones known to have such close ties to Gorgon. Outside of them, there should not exist any goddess who held such obsession toward her.
And first of all—Anna was certainly not Athena.
Athena was the daughter of Zeus, king of the Greek gods. Her myths were many, her status equivalent to that of Ishtar in Mesopotamian mythology—a great goddess of wisdom, celebrated throughout history. Everything about her legends contradicted Anna's behavior.
Nor could Anna be Stheno or Euryale.
Those two goddesses existed purely as completed embodiments of the concept of "idol," possessing virtually no powers aside from charm, and no combat ability whatsoever—completely unlike the battle-capable Anna.
Which left only one conclusion.
"You are Medusa, aren't you?"
Rozen's voice was quiet—yet it resounded across the battlefield like thunder.
"What—!?"
Gorgon's pupils contracted sharply, her expression twisting in shock.
"...!?"
From every corner of the battlefield, even within Chaldea itself, those present were shaken to their core by Rozen's words.
Only Anna lowered her gaze, bowing her head in silence.
That response alone confirmed the truth of Rozen's words.
"Impossible… impossible… impossible…!"
Gorgon recoiled in horror as though she had seen a ghost.
If Anna was Medusa, then didn't that mean—they were one and the same?
For Gorgon was Medusa, transformed after devouring her elder sisters.
If Anna was Medusa—then Anna was also Gorgon.
Such a thing—
Such a thing—
"Impossible!"
Gorgon shrieked in disbelief.
And yet—it was not impossible.
For this had happened before.
Back in the First Singularity, both Elizabeth and Carmilla had manifested—two Servants who were, in truth, the same being.
One was her maiden self, not yet grown; the other, her matured self, fallen into the sins of a vampire.
Anna and Gorgon were simply another such case.
"If I'm not mistaken—you are Medusa in her youth, before she grew into her true self. At this point, like your sisters, you were still a completed embodiment of mankind's yearning for the male form—an 'idol' goddess. In other words, you are Medusa in her girlhood, are you not?"
Rozen revealed the truth.
"At this time, you had not yet been cursed by Athena. Nor had you developed the differing nature from your sisters that would later emerge as you grew. But you already possessed combat ability—a deviation from the pure 'idol' concept."
Because Medusa was the only incomplete goddess among the Gorgon sisters, from this stage onward she grew stronger and stronger, until finally cursed by Athena, gaining monstrosity, and becoming the monster.
The Anna present here was Medusa before those events. Thus, though she possessed some combat strength, she was not especially powerful—and could still be considered a complete goddess like her sisters.
"The Mystic Eye light you used to counter Gorgon's gaze just now—that was none other than the Mystic Eyes of Petrification, the same as hers."
Rozen gestured to the scythe in Anna's hands.
"And that weapon—you hold the Harpe that Perseus used to slay the Gorgon, do you not?"
In Greek mythology, it was with this blade that the hero Perseus severed Medusa's head, killing her.
Though not particularly powerful in itself—it could not cut steel nor unleash great power—any wound it inflicted could never heal.
Thus it carried the property of nullifying immortality, making it a weapon designed specifically to slay Medusa.
The reason Anna held it must be tied to that legacy.
This blade was directly bound to Medusa's death.
Within a Holy Grail War, which permitted only death as an end, such a weapon would naturally manifest as Medusa's Noble Phantasm.
The fact that Anna wielded it was proof enough.
"You exist here for one purpose—to kill Gorgon, isn't that right?"
Rozen's words were met with Anna's affirmation.
"Yes."
Anna spoke softly.
"I exist because of Gorgon's manifestation—summoned in rebound as Medusa."
When the Grail summons a Servant, for the sake of balance, it may also summon neutral ones.
Gorgon had been summoned as a composite divinity by the Grail. As a rebound effect, Anna too was summoned into existence.
She had only one mission in this era—
To stop herself.
To stop Gorgon.
To kill her, so that she could not continue down her wrongful path.
This—was Anna's true identity.