Prompt: "Shirou confronts his former servant, Moriarty, after his betrayal." — Doc Test
"Trust is a delicate thing," the Archer said, tipping a concoction into his former Master's mouth. "Once lost, it will never be found in the same state as it was before."
Shirou woke with a start as the concoction touched his tongue, but a series of presses on his throat had him quickly swallow it.
"I know not why it was me whom your voice reached," Moriarty continued. "I know not why you still trusted me even after Caster's fall. But none of that matters, does it?"
"Gahk!" The boy tried to cough out the serum, but it was far too late. "W... what..."
"Not what, young man." Moriarty corrected sternly. "Who. It is in my nature to do wrong. Despite all you proclaim about the inherent good of man, you summoned an evil Servant."
"That's—that's not true!" Shirou got out. "I don't—don't think you're a bad person at all!"
"Hm?" He quirked an eyebrow.
"You wouldn't have helped save Tohsaka if... if you were bad."
Moriarty smiled. "Are you familiar with the expression, 'all that is necessary for evil to triumph is for good to do nothing?' Well, evil can conquer by way of doing good. Doing good earns trust, you see, and with trust comes vulnerability. And in vulnerability..."
Moriarty motioned to the monitors behind him. They displayed the burning wreckage of Fuyuki City, skeletons of skyscrapers and already crumbling ruins all that remained of his former Master's hometown.
"…comes the opportunity for evil."