Ten Years Prior:

Hell.

There's no other word to describe such a scene.

The trees were burning. The streets were burning. The people, dying and dead, were burning. The sky was ablaze, and the entire world was burning.

It was here that the hooded figure appeared. In the space of one instant and the next, the cloaked figure materialized at the epicenter of hell. The figure appeared without disturbing even a single mote of dust, almost as if he was meant to be here. Almost as if he was wished to be here.

But the figure could not have been here. Because all the figure did was steadily walk away from the center of hell. But that's impossible. Even if his body was chiseled from marble, even if his heart was carved from rock, it is impossible to walk away from such a scene. It is impossible because no one who isn't empty, who isn't heartless, could walk through such a hell without trying to save someone, anyone. And the figure wasn't empty, nor was he without a heart.

So the figure must be a mirage, a phantasm caused by the heat. That is the only explanation for how he can exist here and yet merely walk away. Walk while the world burned to cinders around him. Ignoring the dying pleas and living gasps around him, the figure walked away from the blaze, with an ordinary, empty, sheath by his side.

Nothing other than the figure will survive this hell. Neither those who were struggling to save others at the price of themselves. Nor those who struggled to be saved at the price of others. Even the one who loved humans above everyone else, who killed humans to save humans, who killed his heart so that he can save the world. Even the not-Guardian, the one who was known as Kiritsugu Emiya will die in this hell, consumed, not by the fire, but by his inability to save anyone.

The hooded figure made his way out of the fire. The figure who could not be real pulled down his hood, revealing raven black hair, and matching eyes. The figure which must have been a phantasm gazed at the clouding sky, and said...

"I am sorry."

He was answered by a downpour of rain, which slid down his face like tears.