The Church!
Kirei Kotomine, the man responsible for overseeing this Holy Grail War, father of Mapo Tofu, supervisor of the Holy Grail War, and secret ally of Tohsaka Tokiomi.
Kirei Kotomine was in a terrible mood tonight. Berserker and Archer had caused such a huge uproar that all of Fuyuki City was thrown into chaos, forcing him to step out and take the blame. What truly vexed him was that perhaps he was too old to keep up with the times—Fuyuki City's residents possessed far greater psychological resilience and imagination than he had expected. They had unanimously concluded that Aliens were responsible.
"What the hell? I can't even take the blame if I want to!" Kirei Kotomine shook his head helplessly. What exactly had he been jumping through hoops in the middle of the night for?
Danzo: "..."
Collecting himself, Kirei Kotomine addressed the empty church before him. "Everyone, the Holy Grail War is currently facing a grave crisis. According to the intelligence we have gathered, Caster's Master is the perpetrator behind the serial kidnapping cases that have recently stirred up all of Fuyuki City."
Caster's Master, Ryunosuke Uryu, belonged to a species abundantly produced by the Type-Moon World—murderers. He was an artist who claimed to pursue the true meaning of death.
Normally, the Church would not involve itself in cases such as serial killings. But once this murderer had inexplicably been chosen by the Holy Grail as a Master, everything had to be redefined.
Before becoming a Master, Ryunosuke Uryu had carefully handled every crime scene, displaying exceptional skill at concealing evidence and misleading investigations. He had the makings of an excellent assassin. But after summoning an equally deranged Caster, he no longer bothered hiding. Together with Caster, he brazenly used magecraft and openly left mutilated corpses strewn everywhere.