If Irisviel had come to that conclusion, it was because when she met Yoru Machi again, he had asked her quite a bit about what had happened over the past ten years.
If Yoru Machi had not truly vanished and had instead been living in this world all along, then there was no way he could have known nothing about what had happened during those ten years.
So the truth was nothing like what Sakura had said. Yoru Machi had not abandoned her and ignored her for a full ten years.
Unfortunately, no matter how Irisviel tried to explain it now, the rampaging Sakura could no longer hear her.
Because her subconscious rejected the unbearable answer that she had been abandoned, the darkened Sakura treated everyone present as enemies and stubbornly believed that they had taken away the only person who loved her!
Seeing Sakura in pain, Medusa immediately radiated killing intent so dense it was almost tangible.
As a Heroic Spirit, she was quite pure and did not even possess a clear distinction between good and evil. But Medusa had one iron rule: anyone who hurt Sakura had to die!
"Neighhh—!"
As a winged white horse descended from the sky with a whinny, Medusa vaulted onto its back and activated her Noble Phantasm, dramatically strengthening the Phantasmal Beast she rode.
The winged Pegasus was an extremely famous Phantasmal Beast in mythology, and the only woman able to ride such a heavenly horse was naturally the youngest of the three Mythological Gorgon sisters.
According to legend, Pegasus had been born from the severed neck of Medusa's decapitated head, or perhaps from the pool of blood that had dripped from it.
Rider's Reins—this was Medusa's strongest Noble Phantasm. As an A+-rank Anti-Army Noble Phantasm, it possessed overwhelming offensive and defensive power.