A voice slithers from the darkness, steel on stone. It slinks beneath the pouring rain to hit every last one of the men standing outside the cave with such force it feels like a hit to the stomach.
"Each of you knows the rules."
They do. Each of them knew long before coming here. They stand at the mouth of the cave, all but one clad in strong metal, swords at their sides.
All but one.
Each knows the rules. Older than time, they had been told. Someone, long ago, had carved them in a familiar language outside the cave entrance, too. A warning from a people far older and more broken than theirs. Only the greatest warrior may face it.
And beneath it, All the great warriors have failed.
One of the assembled, a young warrior-king, steps forward. Something in the air shifts, gold-black, and he is made to stop.
"I am Arthur, son of Uther," the warrior-king announces, voice as sure as his footsteps.
"Ruler of Camelot," the voice returns. Its words reverberate in stone and makes their bones shake. Even the proud king turns his head slightly away to escape the weight of the voice.
From beyond the strange barrier, deep in a darkness that must have been there before the creation of the world, two eyes swim into focus. Each is larger than a man, and is only different from the rest of the darkness because something had willed them to see it. Because, despite the palpable darkness beyond, its eyes are somehow darker still.
"He who wields Excalibur, forged in dragon's breath. He who leads men and commands hearts. The Once and Future. You would assume to face me?"
"You are called Azrail," the young-king replies. "And I was bid here by the people to face you. I will do as I must."
A laugh, then, deeper and older than the mountains, like an avalanche of stones. The men surrounding the king clench their jaws against the noise. The eyes still do not blink.
"You know the rules. You may not face me."
Arthur shifts his stance to face the beast more head-one. He adjusts his grip on his sword. "I am the only one who can."
"No," the beast called Azrail replies. "You are not."
"The rules are clear," King Arthur returns. "Anyone who approaches must allow their greatest warrior to engage you in battle."
"Greater men have tried, King Arthur," Azrail says, "and greater men have fallen."
A flash of teeth in the darkness, larger than any man and malevolently sharp.
"He is the greatest warrior among men. He is quicker of hand, surer of foot, nobler of heart than any other," one of the knights replies, one with curly dark hair and a gentle face.
"He is not," Azrail replies.
"Then surely he is the greatest warrior of this group," another contends, red hair plastered to a pale forehead. "He is sharper of mind, faster of steel, greater of spirit than any of us."
"He is not."
The king furrows his brow. "Who would you face, then?"
"He knows," Azrail says, and the eyes and teeth recede into the darkness. "And he is the only one who may enter and face me."
The men all look at each other. All except one. A single man, standing at the back, the only one who approached without armor, sword or shield, presses his lips into a line. An expression part grimace, part determination.
But no fear.
The rest of the men try to move forward. Each are stopped at the mouth of the cave, by the shimmering veil and the oppressive darkness curling on the other side.
"None of us can enter," King Arthur calls. "Surely you will face one of us."
"I will."
The man at the back moves forward. One of the men who had spoken earlier moves to stop him, but is brushed away.
"Merlin," the warrior-king says, starting toward the other man. "It will not let us through."
The man named Merlin stops briefly at the barrier and inclines his head toward the king in a gesture that is somehow neither deference nor insolence. It is simply an acknowledgement of the other man.
Then he steps forward.
Azrail's laugh shakes the rocks of the cave.
Merlin stands with his back to the other men, shoulders straight, chin up, and watches as Azrail comes into focus.
The stories were correct. This beast–demon, devil, abomination–is larger than a mind could truly comprehend. Its eyes are black pools, consuming within them any available light. Nothing reflects there. Its teeth are twice as tall as the man standing before it, each glistening with dark stains and stinking saliva. Its skin is reptilian, its maw stretching obscenely into something resembling a smile. Its neck disappears into the oppressive darkness behind it.
"Your name, warrior," Azrail demands, lowering its face to look at the man before it.
"Merlin of Ealdor," the man replies. His voice is sure and strong.
"Merlin," Azrail replies. "Emrys. Master of life and death. Son of the Triple Goddess. Magic incarnate. Sword and shield of the Once and Future King. War-mage. Warlock. Killer, healer, warrior, peace-maker. You have come here to face me at last."
"Emrys?" a man in armor echoes.
"Magic incarnate," the warrior-king murmurs.
Merlin ignores them. He takes a step forward, and despite every instinct the other men behind him may have, several try to follow. The barrier stops them.
"I have come here to kill you," Merlin replies.
And something changes. Something about him, something about the world, shifts. His words are a blade, cutting through the darkness, revealing the body of the demon, glowing dimly with a fire hidden behind its scales. The cavern, though perhaps deeper and larger than the very mountain holding it, seems to barely contain its serpentine body. Large wings scrape against stone, though the leathery skin between rots from its skeletal frame.
Though the man before him should look small, he doesn't. His figure no longer seems so lanky or fragile. He is tall, broad-shouldered. His stance is sure, almost arrogant, the way he plants his feet and lets his hands hang loosely at his sides.
"Come, then, Merlin Emrys of Ealdor, and show me whether the prophecies of men are still whispered to them by the fates, or if they are just stories to keep away my darkness."
"If the prophecies of men are true, then we both know I am to earn another name today," Merlin replies, taking a step forward.
The horrible smile widens, letting loose a stench of decay.
"Come, Merlin Emrys. Let us all see whether you will earn your title in the annals of men today as God Killer."
Merlin steps into the darkness.