Amakusa Shirou left.
After learning of the deaths of Semiramis and the other Red Faction Servants loyal to him, Amakusa Shirou admitted defeat. He then left Trifas, giving up both the Greater Grail and his identity as Shirou Kotomine.
He chose to travel the world until he found another miracle that could truly save all of humanity.
"That is Amakusa Shirou's full account."
Inside a church in Sighișoara, Ruler Jeanne d'Arc was explaining the Amakusa Shirou incident from beginning to end to a black-haired priest.
"I understand. Thank you for your cooperation, Saint Jeanne d'Arc."
The priest nodded slightly and recorded what Jeanne d'Arc had told him. His East Asian face, so similar to Amakusa Shirou's, left her with a strange feeling, especially given his name.
"Not at all, Father Kirei. I was merely doing my duty."
The black-haired priest was named Kirei Kotomine, legally the younger adoptive brother of "Shirou Kotomine."
The Holy Church backing "Shirou Kotomine" naturally owed an explanation for his betrayal and his attacks on the other six Red Faction Masters sent by the Mage's Association-hypnotizing them and stealing their Command Spells.
Since "Shirou Kotomine's" adoptive father, Risei Kotomine, had already passed away, his son Kirei Kotomine had to handle the matter in his stead.
Still, the Mage's Association did not press the issue at every turn. After all, as Amakusa Shirou himself had said, even if the Red Faction ultimately won the battle between the two sides, they would still have to fight among themselves to determine the final victor.
Amakusa Shirou had merely brought that infighting forward a little.
Ultimately, those six mages had only themselves to blame for being outmatched. The Mage's Association had common convention on its side, nothing more. Refusing to let the matter go just because they were in