The man is a child his father was gifted with on a pilgrimage in 1967.
The name Kirei is supposedly a word of a prayer.
The father named his son in the hope he would be pure and beautiful.
The boy grew up according to his expectations. Even as a young child, he had morals and good sense, showing such great insight that people thought he was precocious.
The father was delighted to be blessed with a great successor, and the son knew of his father's delight.
It is a great pleasure for a parent to know his child is gifted. That must have been why the man considered him valuable.
―――Understanding this, the boy grew just as his father expected.

There was no doubt.
His inability to love his father was unrelated to meeting the man's expectations.
The boy named Kirei grew up healthy.
……But there was one point.
He could not understand the "beauty" of which his father spoke.

―――One morning, he realized the inconsistency.
He woke up, raised his head, and knew.
He was not sure why he understood at that moment.
No, he wondered why it took him so long to realize.

In either case, he knew what he had forgotten.
His father prayed for him to be beautiful and named him Kirei.
That had always been his question.
The things his father considered beautiful…
The boy had never considered beautiful.

It was as simple as that.
He considered moths beautiful instead of butterflies.
He considered poisonous plants beautiful instead of roses.
He considered the evil beautiful instead of the good.
He had a common man's sense of morality, recognizing that it is correct to be good.
But by his nature, the boy was only interested in the exact opposite.

Nobody can understand the agony he felt.
Even Kotomine himself was never certain whether it was agony or not.

But he worked hard.
He tried to be pure and beautiful, and pursued something he did not have from the start.
Shaving away the skin, ripping off the flesh, and dislocating the bones.
He even tried looking within his body for what he could not find in his mind.

His father spent over ten years on his pilgrimage wearing thorned shoes.
The distance he walked could stretch to the moon.
It was not for physical pain. For missionaries, the mental pain is far more significant.
The boy abstained from eating during their pious act.
If he was a sinner by nature, then according to the morals he believed in, he needed to punish himself to maintain balance in the world.

Ten years passed.
Unable to reach the epiphany he sought, he arrived at a single conclusion in its place.
It was simple.
In short, he did not have the sense to feel normal happiness.
Good matters that people consider right and find happiness in.
Philanthropy, trust, glory, safety.
Such matters did not delight him, and it's just that he was born with the deficiency.

All he took pleasure in was the suffering of others.
Murder by others, love and hatred of others, degradation of others.
Such negative concepts were the only things that made him feel happiness.
…His misfortune was carrying a sense of morality, even when he had such a mind.

The child understood at a young age that he was not in accord with the world, and he tried his best to overcome it.
He did not surrender to his condition by indulging in twisted pleasure.
He tried to save himself, one who could not find happiness in any normal way, by turning himself into a normal person.

And the path was his creed; to become a priest and preach life like his father.
――――It is said that God forgives everything.
So he thought God would even save someone "who is not born with it" like himself.

But the result was tragic.
He abode by the rules of God, followed the law, and lived modestly, but he could not find any pleasure greater than the pain of others.
He believed in the church's teaching that forbade immorality, yet immorality was all he had.

But there was no anguish there.
From the beginning, he sought after something that did not exist.
He did not lose something he had, so there was no reason for him to grieve.
The only thing that concerned the priest as he matured was the question "why?"

Yes―――at every crossroads of his life.
The pleasure of committing crimes.
One could understand if he reveled in his own corruption, satisfying his urges by committing crimes himself.
Wealth gained from evil deeds.
It would make sense if he entrapped others out of greed and obtained wealth.

But.
What was wrong with him to not even have the option of turning from good to evil?
Who could possibly be born a defective being and end his life still detached from the world?
Do they not come into this world with the premise that they harm the world?

Call of good sense.
Acknowledgment of morals.
Trial of justice.
Every one of these conclude that evil should not exist.
――――But what about it?
If it should not exist, why are such things created?

―――That is right.
If one has a deficiency, one should not be born.
The world hates evil and removes the faults.
But something that was never wanted was given life.
There are beings that exist to be hated and die.