Kirei Kotomine.
This man is, in all sense, what it means to be an "antagonist".
I'm talking "this guy will make you doubt yourself and your actions while giving the truth that hits home, giving almost no room for a rhetoric or an answer."
He will stop you. He will question you. He will give you the answer you want, but you will curse yourself for ever hearing it.
He holds that villainous side that just loves to watch what your goal in life is,
and see you fail. He will fight you. He will put you down. And like every fantastically sadistic villain, he will mock you in your weakest moments.
AND HIS VOICE.
HIS VOICE IS ALSO GODLY. HHNNNNNNNNNNNNNNNNNNNNNNNNGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
THAT DEEP, SINISTER, PROBING VOICE THAT BOASTS DECIBELS IN HIS AMUSED AND DEVIOUS CHUCKLES.
ANTAGONISTS SHOULD STRIVE TO BE THIS MAN.
And yes, he is a certified priest.
REJOICE, EMIYA SHIRO.