To those versed in the arcane, the Holy Grail is nothing less than an omnipotent wish-granting calice, one that can effortlessly turn the impossible into reality.
"Yeah, I know, it sounds like a con. But it's real. People have even twisted its rules to deceive others."
"As a Servant, the Holy Grail is the reason I can remain in this world. Yet in the Holy Grail War I've fought in, I've shattered it more than once. You'd probably call that a bit of a running tradition?"
"...Making that initial resolve isn't easy. It is an omnipotent wish-granting calice, after all. Who doesn't have a few selfish dreams they'd like to see come true?"